Proposal: Storing Energy, Introducing a "Cell", a Soil Factory on Mars

Steve Stewart · 2023-05-06 23:13:47

Storing Energy, Introducing a "Cell", and a Soil Factory on Mars
Copyright 2023, 2024 by Steve Stewart

Link to this proposal:
http://newmars.com/forums/viewtopic.php?id=10501

INDEX

The importance of Storing Energy on Mars . . . . . . . . . . . . . . . . 2

Introduction to the ClearEdge5(c) . . . . . . . . . . . . . . . . . . . . 3
Figure 3.1 Image from a sales brochure of the Clear Edge 5(c)
Figure 3.2 Diagram of internal workings of a CE5

The "Methane-Oxygen Cycle" . . . . . . . . . . . . . . . . . . . . . . . 4
Figure 4.1 The Methane-Oxygen Cycle

Opening the Loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 5.1 Open loop version of the Methane-Oxygen Cycle
Open loop Methane-Oxygen Cycle
Review

My Proposal of a "Cell" . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Figure 6.1 Functional view of a Cell
Figure 6.2 Example of a composter

The Air in a Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 7.1 Example of how breathing apparatus might look
Figure 7.2 Image from Dr. Chris McKay - Terraforming Mars
Removing Oxygen from the Air
Figure 7.3 Methane-Oxygen Cycle open loop oxygen and water
Different view of the same process
Figure 7.4 Different version of a Cell's functional diagram
Burning methane in a Cell
1) Carbon monoxide (CO)
2) Nitrogen dioxide (NO2)
3) Impurities in natural gas

Harvesting Carbon and a Martian Soil Factory . . . . . . . . . . . . . . 8
(Part 1 of 2)
Harvesting carbon from the Martian atmosphere
Figure 8.1 Example of natures "capture and hold" system
The importance of carbon
Note: Cells produce soil

Harvesting Carbon and a Martian Soil Factory . . . . . . . . . . . . . . 9
(Part 2 of 2)
Hydroponics vs Soil
Figure 9.1 List of recommended books
Why "Turning Mars Green" will not work

How the Martian Atmosphere is Brought into a Cell . . . . . . . . . . . 10
How much nitrogen comes in with Cheat?
Figure 10.1 Example of a fractional distillation machine
Figure 10.2 Image from Marspedia
The Martian
How vacuum pumps work
Figure 10.3 Principle of operation for a vacuum pump
Figure 10.4 Large vacuum pump
Burning methane cleans the air in a Cell
Other ways of cleaning the air
Figure 10.5 Advertisement for an HVAC ultra-violet light
Figure 10.6 Example of an ultra-violet light in HVAC systems
Cleaning the air with plants

How to build a Dehumidifier that Doesn't have any Moving Parts. . . . 11
Figure 11.1 Functional diagram of a dehumidifier
Figure 11.2 Personal photos taken at Pioneer Village
Figure 11.3 Image of Icy-Ball refrigerator
Figure 11.4 List of RV refrigerators
Figure 11.5 List of absorption refrigerators for the home
Figure 11.6 Wikipedia image of the nitrogen cycle
Figure 11.7 Diagram of absorption refrigerator cooling cycle
Figure 11.8 YouTube Video: IcyBall & Parabolic Mirror

The Air Pressure Control System. . . . . . . . . . . . . . . . . . . . . 12
Figure 12.1 Tank that separates CO2 from the other gases
Figure 12.2 Refrigerant tank with two valves.
Monitoring the level of liquid CO2
Figure 12.3 Example of refrigerant scales.
The carbon cycle problem
Figure 12.4 Image from presentation by Bryce Myer
Normal operation of the Air Pressure Control System
Graphical description
Figure 12.5 Percentage of gases in a Cell
Figure 12.6 When level of filler gas goes up CO2 goes down
Figure 12.7 When level of CO2 goes up O2 goes down
Figure 12.8 Net result of increasing filler gas
Summary
Less common operation of the Air Pressure Control System

Martian Resources Out of Thin Air . . . . . . . . . . . . . . . . . . . . 13
Harvesting nitrogen from the air
Uses for other gases
Figure 13.1 Example of a fractional distillation machine
Uses for CO2

How Much Oxygen Does a Cell Produce? . . . . . . . . . . . . . . . . . 14
Figure 14.1 Floor plan of a Cell
Figure 14.2 Floor plan of a Cell with dimensions (English units)
Figure 14.3 Floor plan of a Cell with dimensions (Metric units)
Figure 14.4 3D cutaway view of the Cell described
How much methane does a Cell require?
Figure 14.6 Cubic meter of methane and oxygen
Figure 14.7 One cubic meter of methane reacts with oxygen
If the methane were burned, how much heat would be produced?
Figure 14.8 Diagram of a burner in a Cell
If all the methane were used in a CE5, how much electricity/heat?
Figure 14.9 Diagram of a CE5 in a Cell
Note: the amount of oxygen stored is always equal to the amount produced by a Cell
Figure 14.10 A Cell with 13,000 liters of oxygen to be removed
Another thing to note

Metrics in a Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Metric #1: Oxygen created per unit of volume
Metric #2: Ratio of area of plants to area of building
Figure 15.1 Cell with 12 trays of plants
Figure 15.2 Cell with 6 trays of plants
Metric #3: Percentage of soil per unit of volume
Figure 15.3 Cell with 6 trays of plants
Metric #4: Amount of food produced per unit of volume
Metric #5: ACH - Air Changes per Hour
Conclusion to metrics

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Review of energy storage
Other ways of storing energy
Types of plants
Composting on Mars
Figure 16.1 Example of a composter
Composting enables recycling human waste
Figure 16.2 Screen capture of Gabe Browns video
Closing the loop
Harvest rotation
Figure 16.3 Cell with 6 trays of plants
Figure 16.4 Example of a "Dual-Cell"
Grain crops on Mars
Figure 16.5 Screen capture of Gabe Browns video
Features of a Cell
Figure 16.6 Cell with Discretionary Space
A Cell is compatible with other proposals, including the Moon
Figure 16.7 Another view of proposed "Ice House"
Figure 16.8 Proposal displayed in London Nov 2016

Link to this proposal:
http://newmars.com/forums/viewtopic.php?id=10501

tags
#spacesettlement #SpaceX #marsexploration #MarsSociety #Mars

Last edited by Steve Stewart (2024-10-05 04:44:27)

Steve Stewart · 2023-05-06 23:16:38

The Importance of Storing Energy on Mars

First I'd like to quote something that GW Johnson had said and that I agree with 100%.

Index --> Human missions --> Settlement design
post#304 (Page 13)
I think this discussion suffers from relatively-undefined terms, as well as an unclear overall goal.
The terms "base" and "outpost" are usually associated with small numbers of people and smallish, temporary housing for them. The term "settlement" is usually associated with substantially-larger numbers of people, housing for all of them, and a sense of permanence. In the extreme, we are talking about cities.
Using those definitions, "settlement" is NOT what you do in the initial landing or landings on Mars (or the moon, or anywhere else). WRONG GOAL!!! You are very far from being ready to do that! You do NOT yet really know "for sure" how to "live off the land". That appropriate-goal lesson is centuries old, even here on Earth. Read your history.
What you do initially is establish a "base" or "outpost" with a small crew, quite probably more than one of them, and try out the techniques and hardware (brought from home) that might possibly enable you to "live off the land".

I'm taking Dr. Johnson's good advice by defining the type of base being presented in this proposal. My opinion of the first Martian base, and this is just my opinion, is to first have a base or an outpost as Dr. Johnson described. I view the first Martian base as having a minimal crew of less than 10 people. I then see the base growing to 20 people, later 30, eventually 50, and so on. As Dr. Johnson described, and I have always believed, is that many things must be tried and learned as the base expands. In this proposal I am referring to a small base whose objective is to grow. I am not proposing a settlement with a large population of the general public.

I am proposing different ways of storing energy for a base that has limited resources. I'll also share my ideas on a growing area for plants. Something I call a "Cell". And I'll introduce a few of my thoughts on Martian agriculture. I have to introduce all of these topics at the same time, because they all work together as a single system. Therefore, I cannot explain any one of these concepts, without explaining how it works with the others. Everything I'm about to describe I have designed it to be as simple as possible. The idea is for much of this to be built on Mars, or at the very least replacement parts can be built on Mars.

There have been several threads on this forum about solar energy that have identified the need for storing power. If Mars were using solar energy, excess electricity would need to be produced and stored during the day so that it can be available at night when solar energy is not available. It turns out that solar power is not the only source of electricity that could benefit from the ability to store power. I'm making the argument that any time a source of electricity, whether it be from solar, nuclear (such as Kilopower), or any other type, all sources of electricity can benefit from a method of storing energy, because storing and retrieving energy reduces waste.

For example, suppose a source of electricity is generating 30 kW and only 20 kW is being used. In that case 10 kW is being wasted. Figuring out ways to store energy will reduce this form of waste. Even if the storage method isn't all that efficient, it will be effective because it is recovering energy from what would have been total waste. Suppose someone came up with a way of storing electricity that is 10% efficient. If 10 kW were being wasted as was just described, a system that was 10% efficient would still be able to produce 1 kW of power from what was once considered total waste.

Another benefit of storing extra electricity is that it will increase the peak power load of a Martian base. Suppose the first Martian base has a circuit that is powered by one 30 kW kilipower. At no time would this circuit be able to consume any more than 30 kW at one time, not even for an instant. But if the base had the ability to store energy, and that energy source could supply 5 kW of electricity, then the circuit would have a peak load of 35kW. If the method of storing extra electricity over a few days could provide 70 kW for a short time, then the circuit would have a peak load (surge load) of up to 100 kW.

The takeaway is that the peak load for a Martian base can be increased, and the amount of electricity being wasted can be reduced, by figuring out ways of storing excess electricity. This is true regardless of the energy source.

Last edited by Steve Stewart (2024-08-04 00:27:28)

Steve Stewart · 2023-05-06 23:17:40

Introduction to the ClearEdge5(c)

Storing energy as methane and oxygen has been discussed on this forum. If energy were stored in this way on Mars, a ClearEdge5(c) could be used to convert methane and oxygen directly into electricity without having to burn methane. Instead, the device reacts methane with oxygen, producing electricity and heat in the process.

As shown in a sales brochure below, the ClearEdge5(c), or simply CE5 as it was known, could produce 5 kW of electricity while at the same time produce 5 kW of heat. The excess heat generated in the process of making electricity is used to heat a home or building. The device makes highly efficient use of natural gas (methane) in applications where both heat and electricity are needed.

Figure 3.1 Image from a sales brochure of the ClearEdge5(c)

The CE5 was manufactured by a company called ClearEdge Power(c). From what I've read the device worked rather well. But it was expensive ($56,000 US dollars), which is probably why the CE5 is no longer made and the company is out of business. Even though the CE5 is no longer produced, its principles of operation can be used on Mars.

The CE5 removes the need of having to store highly volatile hydrogen. Instead, the much more stable methane is stored and hydrogen is extracted from methane on demand. A hydrogen extractor is used to remove hydrogen from methane. Hydrogen and oxygen are then used in a fuel cell. According to Wikipedia, fuel cell efficiency varies from 40% to 60%. Meaning that between 40% and 60% of the stored chemical energy (hydrogen and oxygen) is converted back into electricity, with the remaining energy (60% to 40% respectively) being lost as heat.

Figure 3.2 Diagram of internal workings of a CE5.
On the right is the hydrogen extractor, labeled "Fuel Processor".
It extracts hydrogen from methane.
The hydrogen is then used in the fuel cell along with oxygen from the air.

The CE5 uses some of the wasted heat and water from the fuel cell to make steam. Steam is needed for the hydrogen extractor. The hydrogen extractor does use some electricity in addition to heat and steam, but the amount of electricity consumed is much less than the amount of electricity being produced by the fuel cell. The end result is, as was shown in the sales brochure above, is that up to 5 kW of electricity can be produced at a time, resulting in 5 kW of heat being produced. Therefore the CE5 is approximately 50% efficient.

The amount of electricity being produced by a CE5 at any one time is equal to the load. The higher of the load of electricity, the more heat is produced. For example, a 1 kW load results in 1 kW of electricity being produced, along with 1 kW of heat. A 2 kW load results in 2 kW being generated, along with 2 kW of heat, and so on. Note that if the CE5 were used with solar panels on Mars, it would only make electricity at night when solar energy is not available. This means the CE5 would be generating electricity at a time when heat is needed most. Below are YouTube videos about the ClearEdge5(c).

ClearEdge Hydrogen Fuel Cell

What Is A Fuel Cell: ClearEdge Power

ClearEdge Hydrogen Fuel Cell
(Tour of plant)

Buy Fuel Cells for your Home
News report from a TV station in San Diego, California

ClearEdge Wants To Put A Refrigerator-Sized Fuel Cell In Your House
August 24, 2011

ClearEdge Power to make fuel cell for data centers
August 23, 2011

Last edited by Steve Stewart (2024-08-04 00:28:27)

Steve Stewart · 2023-05-06 23:18:59

The "Methane-Oxygen Cycle"

When we talk about efficiency, we are usually referring to what percentage of energy is lost as heat. For example, if a car battery is said to be 90% efficient, it means that 10% of the energy used to charge the battery is lost as heat. If a gasoline engine is said to be 30% efficient, it means that 70% of the energy in the fuel is lost as heat. The percentages will always add up to 100% because all of the energy going into a system is always equal to the amount of energy going out of that system. This is a basic law of thermodynamics. It has to do with the fact that energy cannot be created nor destroyed, it can only change forms. (Law of conservation of energy).

If a CE5 were used to make electricity and the wasted heat were used to warm a Martian base, then the so-called "wasted heat" would not be wasted at all. The process would be considered 100% efficient because all of the chemical energy, stored as methane and oxygen, would be recovered. Some of it as electricity and the rest as heat.

I made the diagram below to illustrate the process. I call this the "Methane-Oxygen Cycle." The bottom of the figure shows water and CO2. I've labeled water and CO2 as being a "low energy state". Using the Sabatier reactor shown on the left, water and CO2 are converted into methane (CH4) and oxygen (O2). The Sabatier reactor consumes energy in the form of electricity. This electrical energy is stored as chemical energy in the form of methane and oxygen. For that reason, I've labeled methane and oxygen as a "high energy state" at the top of the diagram.

Figure 4.1 The Methane-Oxygen Cycle

The stored chemical energy, in the form of methane and oxygen, can be released in several ways as shown on the right side of the diagram. Whenever methane and oxygen react with each other they form two things, water and CO2 (see below). The stored chemical energy is released in the process.

One way to release energy stored as methane and oxygen is to simply burn the methane in the presence of oxygen. This could be done with a small natural gas furnace located in a greenhouse. Suppose the furnace is ran at night to keep the greenhouse warm. In this case, all of the stored chemical energy is released as heat. As long as all of this heat is needed, then this method of storing energy would be considered 100% efficient. Because 100% of the energy stored as methane and oxygen would be recovered at night as heat.

Another way to release the stored chemical energy would be to use an engine that runs on methane. There are many types of engines that could be used, such as piston engines, turbine engines, rotary engines (Wankel), Stirling engines, steam engines, and so on. Regardless of the type of engine used, an engine running on methane would convert the stored chemical energy into mechanical energy and heat. An engine could be used to power various manufacturing processes, or various types of equipment on Mars. In this scenario, the stored chemical energy would be converted into mechanical energy and heat. This process would be considered 100% efficient as long as all of the mechanical and heat energy were used.

As has been mentioned in this forum, mechanical energy could be used to run a generator to produce electricity. In that case, some of the mechanical energy would be converted into electrical energy. This scenario would also be considered 100% efficient, as long as all of the mechanical energy, electrical energy, and heat energy were used.

A third way to release the energy stored as methane and oxygen is to use a CE5, which produces electricity without burning methane. This results in some of the stored energy being released as electricity and the rest as heat. And once again, if all the energy is used (electricity and heat in this case), the process can be considered 100% efficient.

Last edited by Steve Stewart (2024-08-04 00:29:27)

Steve Stewart · 2023-05-06 23:19:59

Opening the Loop

The Methane-Oxygen Cycle that was shown in Figure 4.1 is a closed loop system. In theory, this closed loop system could be repeated over and over indefinitely, as long as none of the elements in the loop are lost (hydrogen, oxygen, and carbon). However the cycle would be more productive if it were open loop.

For example, in Figure 4.1 water is created when methane and oxygen react and release energy. This clean water is then recycled back through the Sabatier reactor. There are advantages for not using pure (clean) water in the Sabatier reactor.

The Sabatier reactor uses electrolysis to provide hydrogen for the Sabatier reaction. The more conductive the water, the faster hydrogen (and oxygen) comes out of the water. Pure water is a poor conductor of electricity. This is because pure water does not contain any ions. When water contains impurities it also contains ions. Impurities make dirty water a good conductor of electricity.

Does Water Really Conduct Electricity?

If water were to be extracted from Martian regolith, it will no doubt contain many impurities, as water is known as the universal solvent. These impurities cause water to be a better conductor of electricity. Dirty water can be used for electrolysis in the Sabatier reactor, as shown below in Figure 5.1 (bottom left).

Many of us have seen electrolysis demonstrated in school, often using the Hofmann Electrolysis Apparatus. Usually acid is added to the water to make it a better conductor of electricity (to create ions). Adding acid also makes the water corrosive and it tends to eat away at most any metal. This is why the Hofmann Electrolysis Apparatus uses platinum foil for the electrodes, as platinum is highly resistant to corrosion. This is because platinum is a "noble metal" that is highly nonreactive.

Figure 5.1 Open loop version of the Methane-Oxygen Cycle

In addition to being a better conductor of electricity, using dirty water with electrolysis provides the benefit of purifying water. Electrolysis purifies water by removing pure hydrogen and pure oxygen from dirty water, leaving the impurities behind. Therefore a byproduct of the Sabatier reactor, and electrolysis in general, is the purification of water.

Open loop Methane-Oxygen Cycle

Once methane reacts with oxygen to release the stored chemical energy, it creates water and CO2. The clean water exits the loop and is available for use somewhere else. (Bottom right of Figure 5.1). On the bottom left of the Figure 5.1, dirty water enters the loop replenishing the clean water that was removed.

Therefore the storing of excess electrical energy as methane and oxygen and releasing it when needed has an additional benefit -- it purifies water. The cycling of dirty water into the loop and clean water out of the loop provides a way of purifying water without consuming any additional energy. That is to say, making the Methane-Oxygen Cycle open loop does not consume any more energy then when the cycle is closed loop. In fact, it might consume less energy since dirty water is a better conductor of electricity. As has been shown, making the Methane-Oxygen Cycle open loop makes the cycle more productive.

Review

Time to review what has been covered so far. Energy can be stored using the Methane-Oxygen Cycle. When doing so, energy can be retrieved as mechanical and/or electrical energy, and/or heat. As long as the excess heat is needed, these processes of storing energy are 100% efficient. Storing energy helps to reduce waste while at the same time increases the peak power output of a Martian base. Using the Methane-Oxygen Cycle not only provides a way of storing energy efficiently, it also purifies water without consuming any additional energy.

Last edited by Steve Stewart (2024-08-04 00:30:28)

Steve Stewart · 2023-05-06 23:21:01

My Proposal of a "Cell"

Before going into more detail about storing energy and the Methane-Oxygen Cycle, I need to pause a moment and introduce something I call a "Cell". I need to illustrate functions of a Cell so I can explain more aspects of the Methane-Oxygen Cycle.

A Cell is a growing area for plants. It creates Discretionary Space that can be used for manufacturing processes, such as making polymers, fiberglass, rubber, fabrics, or whatever needs to be made.

The Cell I'm about to describe is designed to be built with as few resources as possible, with one of those resources being labor. If an early Martian base has a low demand for labor, then it can progress and expand with a minimal number of people. The Cell is designed so that all components of a Cell can be made, or at least replacement parts can be made, on Mars.

This goes hand in hand with what GW Johnson described and I quoted above in post#2, the "Base" is "usually associated with small numbers of people...". And the Cell is designed to "try out the techniques and hardware (brought from home) that might possibly enable you to 'live off the land'." Eventually, more Cells can be built with the first Cell providing some of the resources needed to build additional Cells.

A Cell can be located above ground in a greenhouse that uses sunlight, or in a hybrid greenhouse that uses both sunlight and artificial light. Or it could be located in an enclosed building above the Martian surface, or below the surface in an underground habitat. Regardless of a Cells location, its function remains the same. An example of a Cell is shown below. Note it is not drawn to scale. It is only drawn to illustrate Cell Function.

Figure 6.1 Functional view of a Cell (Not drawn to scale)

Figure 6.1 shows several shelves with the tops colored green. The green is to represent plants growing in soil. The Cell has a small engine [1] that runs on methane. The engine turns a fan [2] that pulls air through a dehumidifier [3] and a mineral wool filter. (Mineral wool can be made as a byproduct of smelting iron).

The dehumidifier runs on heat alone and does not have any moving parts. In theory, the dehumidifier could run for over 100 years, possibly centuries, without ever wearing out. Later in post#11, I'll explain how such a dehumidifier works. The fan makes the dehumidifier more efficient, but it is not needed for the dehumidifier to work.

To the right of the dehumidifier [3] is a water tank [4] that stores water that drips out of the dehumidifier. The water can be used to water plants using a gravity fed watering system. To the right of that is a second water tank (not shown) that holds dirty water. The Cell also contains a composter (Not shown. Example shown below).

Figure 6.2 Example of a composter

The second water tank with dirty water can be used in the Sabatier reactor. If impurities in the dirty water are not toxic, then dirty water can be used to water plants using a gravity fed watering system. This would conserve the clean water that is in the water tank [4].

If the dirty water used to water plants contain Essential Elements, such as calcium, sodium, chlorine, etc, it would help feed the plants and enrich the soil. Essential Elements are elements that plants and microbes need to make their bodies, and we need to make ours. (More about that later). Most Essential Elements are water soluble.

Plants help to purify water. They take in dirty water at their roots and release clean water from their leaves in the form of humidity, where it gets picked up by the dehumidifier (transpiration).

As previously mentioned, burning methane creates two things, CO2 and water. Therefore burning methane in a Cell greatly increases the humidity. The dehumidifier removes water from the air and it drips into the storage tank [4]. The water that ends up in the storage tank [4] is the clean water that was shown in the open loop Methane-Oxygen Cycle in Figure 5.1. The clean water can be removed from the storage tank [4] and be used somewhere else on the Martian base. This is an example of clean water leaving the loop that was shown in Figure 5.1.

Dirty water is used in the Sabatier reactor, which is located somewhere outside the Cell. Methane from the Sabatier reactor is piped into a Cell much like natural gas is piped into a home. Plants are able to produce most of the oxygen needed to react with methane. (I'll provide oxygen production numbers later in post#14). If additional oxygen is needed, some, or all, of the pure oxygen from the Sabatier reactor can be safely released back into the Cell. (More about that in post#14).

Dirty water that doesn't contain anything toxic can be used to water plants. Dirty water that does contain something toxic can be used in the Sabatier reactor. (As mentioned the Sabatier reactor uses electrolysis to extract hydrogen from water).

If a Cell contains a burner (natural gas furnace) and a CE5 in addition to an engine, then heat from any of these devices could be routed to the dehumidifier to power the dehumidifier. There are pro's and con's to using each of these devices as I will explain later.

Having three different devices in a Cell that can react methane with oxygen gives the astronauts flexibility. Any combination of these three devices could be used at a time. One at a time, two at a time, all three at the same time, or none at all. Having all these combinations as to which pro's and con's to select, makes the Methane-Oxygen Cycle adaptive.

If 100% of the stored energy is needed for heat in a Cell then the gas furnace could be used. If some energy is needed for mechanical power then an engine that runs on methane could be used. If more electricity and less heat is needed, the CE5 could be used. As the demand for heat, mechanical power, and electricity changes, using different methods of releasing the stored chemical energy, stored as methane and oxygen, can be used to match the demand.

Because all of these devices (burner, engine, or CE5) are located in the Cell, any "wasted heat" from these devices will not be wasted at all. The heat will help to keep the Cell warm. As mentioned before, as long as all of this heat is needed, 100% of the energy stored as methane and oxygen will be used, making the process of storing energy 100% efficient.

Last edited by Steve Stewart (2024-08-09 01:22:33)

Steve Stewart · 2023-05-06 23:22:03

The Air in a Cell

The Cell that was shown in Figure 6.1 has a high concentration of CO2 in the air. The percentage of CO2, oxygen, nitrogen, and other gases in the Cell, are allowed to change or "drift". Because the percentage of oxygen and other gases varies, astronauts must wear breathing apparatus when working in a Cell. The breathing apparatus would probably look similar to the one shown in Figure 7.1 below.

The Cell is warm and pressurized, making it a comfortable area for plants and humans alike. The breathing apparatus only needs to cover their face so they are breathing air with the right ratio of oxygen and nitrogen (or some type of filler gas). Astronauts could wear shorts and a T-shirt while working in a Cell, as long as they are wearing breathing apparatus.

Figure 7.1 Example of how breathing apparatus might look.
Image is from PeRSo-DW project, University of Southampton.
Southampton, England

The air in a Cell must contain an adequate amount of oxygen. Not only is oxygen needed for methane to react with oxygen, but plants need oxygen as well as CO2. Contrary to what has been stated on this forum a number of times, plants cannot survive in air that is pure CO2. They must have oxygen or they die.

Both plants and humans must have oxygen in order to get energy from carbohydrates. Humans/mammals eat carbohydrates and breathe in the oxygen they need. Plants make their own carbohydrates through photosynthesis and respire (breathe) mostly at the roots, consuming oxygen in the soil and replacing it with CO2. This causes the air in soil to have a higher concentration of CO2 than the air just above ground.

Soil Science for Gardeners
Working with Nature to Build Soil Health
By Robert Pavlis
Section: Air and Water
(Page 19 in my book)
What you may not realize is that plants also respire, absorbing O2 and giving off CO2. This happens not only at night but also during the day and for the same reason animals do it. The process allows plants to convert sugars into energy, which they need for growth. This takes place in all their parts, but a lot of it happens in the roots; they need to be able to absorb oxygen from the soil, or they die.
This explains why many plants can't grow in areas that are constantly wet. This kind of soil does not provide enough oxygen for roots. It also explains why plants die if you water too much and why some plants just don't grow well in clay soil that does not hold enough air.

When methane reacts with oxygen as was previously described (burner, engine, or CE5), it causes the percentage of oxygen in the Cell to decrease and the percentage of CO2 to increase. (It will also cause a decrease in air pressure).

The amount of CO2 that can be in a Cell is dependent on the plants. According to Dr. Chris McKay, there is no clear upper limit on the amount of CO2 that plants can handle, and that the upper limit of oxygen is set by flammability. The level of CO2 on the International Space Station is quite high. A paper by NASA states:

"ISS CO2 levels predominantly fluctuate in the 3,000 to 5,000 ppm range."

Figure 7.2 Image is from YouTube video with Dr Chris McKay at 3m 0s.
Dr. Chris McKay - Terraforming Mars - 2021 Mars Society Virtual Convention

The percentage of oxygen and CO2 in the air of a Cell is kept in check by reacting more, or less, methane with oxygen. The level of CO2 is kept high enough for plants, but not too high. There was a case on ISS that a type of lettuce did not grow well in the VEGGIE system because the level of CO2 on ISS was too high for that particular type of lettuce. (As stated, the CO2 level on ISS fluctuates from 3,000 to 5,000 ppm -- 0.3% to 0.5%).

The remaining gases in a Cell are filler gases, mostly nitrogen and argon. As the percentage of nitrogen in a Cell increases, argon can be removed so that the majority of the filler gas is nitrogen. Eventually the air in a Cell could be similar to that of Earth. (About a 21%/79% mix of oxygen and nitrogen).

The Cell has an Air Pressure Control System that can add air, or remove CO2 from the air to adjust pressure. As a general rule, air from the Martian surface is brought into a Cell which will cause an increase in air pressure. CO2 is removed from a Cell as needed to lower air pressure. How outside air is brought into a Cell will be explained later in Post #10. Details of how the Air Pressure Control System works will be explained in Post #12.

Removing oxygen from the air

Plants in a Cell produce oxygen while consuming CO2 and water. The oxygen produced by plants is needed for many things on Mars, such as oxygen for astronauts to breathe, aerobic composting, some manufacturing processes will consume oxygen, and so on. A method is needed to remove the oxygen produced by plants from the air so it can be used somewhere else. Removing oxygen would also prevent the Cell from building up with too much oxygen, which could create a fire hazard as well as suffocate the plants. Oxygen concentrators could be used for this purpose, but these devices consume energy (electricity) and have moving parts that will eventually wear out.

How a oxygen concentrators work

Below is a diagram of the Methane-Oxygen Cycle that was shown earlier. This version is an open loop system that separates pure oxygen from the air in a Cell. The Sabatier reactor separates pure oxygen from CO2 and water, this pure oxygen exits the loop (Figure 7.3 top left). Methane from the Sabatier reactor is piped into the Cell where it can be used.

When any of the devices listed in the diagram (burner, engine, or CE5), are running in a Cell, they will consume oxygen and therefore separate pure oxygen from the surrounding air. Notice that none of these devices require an input of pure oxygen. (Although the hydrogen extractor in the CE5 would work better with pure oxygen). Therefore all three devices provide a method of removing (separating) pure oxygen from air without using any additional energy, filters, or mechanical devices such as oxygen concentrators.

Figure 7.3 Methane-Oxygen Cycle open loop oxygen and open loop water.

CO2 and other gases are brought into a Cell from the Martian atmosphere. (How this is done will be explained later in Post #10). Plants consume some of the incoming CO2 and plants produce oxygen. The oxygen from plants is removed from the Cell by reacting methane with oxygen, producing water and CO2. The dehumidifier picks up the water from the humidity in the air and this clean water exits the loop (Figure 7.3 bottom right).

Some of the CO2 created by reacting methane with oxygen and CO2 from the Martian atmosphere ends up being used in the Sabatier reactor, along with dirty water that comes from somewhere else (Bottom left Figure 7.3).

Dirty water that is used in the Sabatier reactor replenishes the clean water from the dehumidifier that exited the loop (Bottom right Figure 7.3).

Pure oxygen from the Sabatier reactor exits the loop and methane is piped back into the Cell (Top left Figure 7.3).

Methane from the Sabatier reactor enters the Cell and reacts with oxygen produced by plants. The oxygen produced by plants replenishes the pure oxygen that left the loop (Top left Figure 7.3). The cycle keeps repeating.

Different view of the same process

Figure 7.4 below shows a different perspective of the process just described. CO2 comes into the Cell from the outside [7]. (As mentioned, how this is done will be explained later in Post #10). Plants consume the incoming CO2 and dirty water and produce oxygen [3]. Oxygen produced by plants replenishes the pure oxygen that left the loop [4].

Oxygen from plants reacts with methane [2], creating CO2 and water. The water [1] is picked up by the dehumidifier and exits the loop [6]. Dirty water is used in the Sabatier reactor [5], replenishing the clean water that left the loop [6].

Figure 7.4 Different version of a Cell's functional diagram.

Most of the water picked up by the dehumidifier comes from reacting methane with oxygen [2], and some comes from the leaves of plants [1] (transpiration).

There are several processes in a Cell that can cause an increase or decrease in air pressure. The Air Pressure Control System will adjust the rate at which CO2 is removed to maintain a constant pressure. The Oxygen Control System will then hold the level of CO2 at a preset value by reacting more, or less, methane with oxygen. This will be explained later in Post #12.

The Air Pressure Control System produces pure CO2 as a byproduct, which is stored, as CO2 has many uses on Mars, as will be explained later in Post #13. The stored CO2 is available for use in the Sabatier reactor.

On the right side of Figure 7.4 CO2 enters the Cell [7], and pure oxygen exits the Cell [4]. The carbon that is left behind from CO2 coming in and O2 going out is consumed by plants and microbes enriching the carbon content of soil. Carbon is an important element for soil function as will be explained later in Post #8.

Also on the right side of Figure 7.4 it can be seen that dirty water enters the Cell [5] and clean water exits the Cell [6], leaving the impurities behind. If the impurities are not toxic and contain Essential Elements, the dirty water is used to water plants. The Essential Elements in the impurities enrich the soil and help feed the plants. This is a way of providing plants/microbes with some of the Essential Elements they need. (Such as calcium, sodium, chorine, etc). As previously mentioned, most Essential Elements are water soluble.

Notice on the right side of Figure 7.4 dirty water goes into a Cell [5] and clean water exits the Cell [6]. This shows that one of the features of a Cell is that it purifies water. Also notice that air from the Martian atmosphere enters the Cell [7] and pure oxygen exits the Cell [4]. This shows that a Cell is capable of processing air directly from the Martin atmosphere (Explained later in Post #10) and producing pure oxygen. Therefore a Cell has more functions than just growing plants.

Burning methane in a Cell

Methane is being reacted with oxygen inside of a Cell. Sometimes it is burned, sometimes it is ran through a CE5 that reacts methane with oxygen without burning it. In both cases, the resulting gases are vented back into the Cell. There is not any ventilation back out to the Martian atmosphere.

The burner is enclosed inside of a metal (fireproof) container so that it is safe to have a flame inside of a Cell. The "absorption dehumidifier" that I'll explain later in Post #11 also has methane burning inside of it. A burner (gas furnace) or "absorption dehumidifier" safely burns methane in a Cell, consuming oxygen in the Cell.

Regardless of whether methane is being burned, or if it is reacted with oxygen in a CE5, either way, when methane reacts with oxygen, it only creates two things: CO2 and water, as shown in the equation below.

Both the CO2 and water are vented back into the Cell, and therefore stays in the Cell. None of the CO2, water, or heat are lost by doing it this way. Any impurities that are in the air of a Cell also end up passing through a methane flame. When impurities pass through burning methane in the presence of oxygen, they are burned off as will be explained later in Post #10.

Keep in mind that a Cell is a growing area for plants, not a living area for humans. As long as the air quality of a Cell is good enough for plants to survive, then the Cell will work as described. Still, we do need to consider what's coming out of a burner, as the exhaust is vented back into the Cell. There are three things to consider when burning methane without ventilation in a growing area for plants. I'll discuss each of these three things separately.

1) carbon monoxide (CO)
2) nitrogen dioxide (NO2)
3) impurities in natural gas

1) Carbon monoxide (CO)

Carbon monoxide is the result of incomplete combustion. As long as the combustion of burning methane is complete, there will not be any carbon monoxide created.

WikiDoc article Carbon monoxide states:
Carbon monoxide is produced from the partial combustion of carbon-containing compounds, notably in internal-combustion engines. Carbon monoxide forms in preference to the more usual carbon dioxide when there is a reduced availability of oxygen present during the combustion process.

Methane has incomplete combustion when there is not enough oxygen available to react with the methane. As mentioned, the oxygen level in a Cell is adjustable. Therefore the level of oxygen in a Cell can be kept at a higher than normal level so as to ensure complete combustion of methane, preventing the creation of carbon monoxide. This coupled with having high quality burners, should eliminate any problem with incomplete combustion, which in turn eliminates any problem with carbon monoxide.

Burning methane in a Cell cleans the air in the Cell. If some carbon monoxide were to be present in a Cell, it would float around the Cell until it passed through burning methane. When it passes through burning methane in the presence of oxygen, it will pick up an extra oxygen atom and be converted into carbon dioxide.

It doesn't take that high of a temperature to get carbon monoxide to react with oxygen and form carbon dioxide. Carbon monoxide oxidation can occur at temperatures as low as 104F (40C), but usually occurs at temperatures above 930F (500C). Methane burns at a temperature of 3,542 F (1,950 C). This is plenty hot enough to get carbon monoxide to react with oxygen and form carbon dioxide.

If need be, a catalyst could be added to the exhaust of a burner to insure all carbon monoxide in converted into carbon dioxide. The hot exhaust coming from the burner would pass through the catalyst before entering the Cell. The problem with this approach is that it adds complexity and more hardware to the system. More supplies (catalyst) would have to be sent from Earth. I don't think a catalyst will be needed, but it is an option if the need arises.

Because burning methane converts carbon monoxide into carbon dioxide, it provides a way of pumping raw air from the Martian atmosphere directly into a Cell without any additional processing. When outside air is brought into a Cell in this manner, I refer to the air coming in as "Cheat", as will be explained later in Post #10.

Air in the Martian atmosphere contains a small amount of carbon monoxide and the raw air from the Marian atmosphere is not processed in anyway. Carbon monoxide and any other impurities in the Martian atmosphere are burned off by pumping the air directly into burning methane. When air is brought into a Cell this way, I refer to the incoming air as "Cheat". More about this process will be explained later in Post #10.

With good quality burners being used, and the oxygen level being adjustable, and burners constantly cleaning the air, carbon monoxide in a Cell is a not an issue.

2) Nitrogen dioxide (NO2)

Another potential problem with the burning of methane in a Cell and venting it back into the Cell is the presence of nitrogen dioxide (NO2). As already stated, reacting methane with oxygen only produces two things, CO2 and water and plants need both. However, with a Cell containing both nitrogen and oxygen, NO2 will form when these two elements pass through a flame of burning methane.

Although breathing nitrogen dioxide (NO2) over long periods time can cause respiratory problems in humans, it turns out that nitrogen dioxide (NO2) in the air can be of benefit to plants. As mentioned, a Cell is a growing area for plants, not a living area for humans. Humans must wear breathing apparatus when working in a Cell (Figure 7.1).

Article: Nitrogen dioxide is a positive regulator of plant growth
Exposing plants that are well supplied with soil nitrogen to gaseous NO2 increases the uptake of nutrients, photosynthesis, and nutrient metabolism so that shoot biomass, total leaf area, and the contents per shoot of C, N, P, K, Ca, Mg, and S (or Fe), free amino acids and crude proteins approximately double over those of control plants, with some exceptions (Table 1). Fruit yield is also increased 1.4-fold compared with control plants (Table 1). An increase in photosynthetic rate under the influence of NO2 has also been reported by Xu et al.

As long as the plants and soil are both healthy, not only will nitrogen dioxide (NO2) not harm plants, it will actually help them to grow. Therefore, having small amounts of nitrogen dioxide in a Cell is not an issue.

How much nitrogen dioxide is created is dependent on a number of factors, including the air pressure in the Cell, the percentage of nitrogen in the Cell, and the percentage of oxygen in the Cell. Each of these things are adjustable. Therefore adjustments can be made to control the rate at which NO2 is produced.

How much nitrogen dioxide is in the air at any given time is dependent on how fast it is created verses how fast it is consumed. How fast it is consumed is dependent on a lot of things, including the number of plants in a Cell compared to the volume of the Cell, the percentage of nitrogen in the air, the amount of soil that is in the Cell, temperature, light intensity, soil structure, moisture, amount of organic matter in the soil, carbon demand placed on the plants by soil microorganisms, amount of mycorrhizal fungi (helpful fungi) in the soil, to name a few. Basically it's dependent on the overall health of the soil and on conditions in the Cell (ie. "weather" in the Cell).

I'll introduced several metrics in Post #15 later. Some of these metrics would effect, or be effected by, the amount of nitrogen dioxide in the air.

Both carbon monoxide (CO) and nitrogen dioxide (NO2) can be reduced by using high quality burners. I do not see carbon monoxide (CO) or nitrogen dioxide (NO2) being an issue in a Cell. However, we do need to consider impurities in natural gas.

3) Impurities in natural gas

The third issue to consider when burning methane in a Cell are the impurities in the methane itself. On Earth, natural gas is mostly methane, but it isn't 100% pure methane (CH4). According to the link below, the methane content of natural gas on Earth can be as little as 65%.

On Earth, natural gas contains many impurities. Many of the problems associated with burning natural gas in homes has to do with impurities found in natural gas.

From PennState College: Natural Gas Composition and Specifications
Raw natural gas also contains water vapor, hydrogen sulfide (H2S), carbon dioxide, nitrogen, helium, and other impurities, such as mercury. Table 12.3 gives some examples of the composition of natural gas produced in three different locations, to give an example that methane content of natural gas can be as low as 65%.

On Mars, methane made from the Sabatier process does not contain hydrogen sulfide (H2S), mercury, benzene, and other harmful impurities found in natural gas on Earth. Therefore burning methane created by a Sabatier reactor does not create the toxins that are created when burning natural gas in homes on Earth.

Although not mentioned in the quote above, natural gas on Earth also contains benzene, which is a problem.

Wikipedia article Benzene states:
Benzene is a natural constituent of petroleum and is one of the elementary petrochemicals. Due to the cyclic continuous pi bonds between the carbon atoms, benzene is classed as an aromatic hydrocarbon. Benzene is a colorless and highly flammable liquid with a sweet smell, and is partially responsible for the aroma of gasoline.

Article: Gas Stoves Leak Dangerous Benzene, Study Says, But You Can Reduce Your Exposure
New research has found that natural gas stoves leak harmful chemicals, even when turned off. The study, published yesterday in the journal Environmental Science & Technology, confirmed previous findings that the fuel used to power gas ovens, stoves, ranges, and water heaters contains dangerous contaminants that have adverse health effects for adults and kids.

Article: Gas stoves pollute homes with benzene, which is linked to cancer
What can you do about gas stove pollution?
Gas utilities have long researched how gas stoves pollute indoor air and even developed new styles of burners that use less gas and emit less nitrogen dioxide. But manufacturers don't use them, saying they are more expensive, harder to clean and consumers aren't demanding them.

High quality burners will be used on Mars, and methane produced on Mars will not have the impurities found in natural gas on Earth. Therefore I don't see the problems with impurities found in natural gas on Earth being a problem with methane create from a Sabatier reactor on Mars.

Last edited by Steve Stewart (2024-09-04 00:19:07)

Steve Stewart · 2023-05-06 23:23:08

Harvesting Carbon and a Martian Soil Factory (Part 1 of 2)

Harvesting carbon from the Martian atmosphere

Plants produce carbon compounds from CO2 in the Martian atmosphere. Some of these carbon compounds, called exudates, leak out of the roots and into the soil to feed the underground biology. The microbes eat the exudates and poop acids, which dissolve Essential Elements in the rhizosphere (area around and directly up against the roots). The roots take up the dissolved Essential Elements, which feed the plant. The plant feeds the microbes and the microbes feed the plant. As Dr. David R Montgomery puts it:

"This steps up an exchange through which both sides benefit from the commerce of the original underground economy."

Carbon is sometimes referred to as the "currency of the soil". It is the driver of the many processes that take place in soil. The carbon in these compounds originates from CO2 in the Martian atmosphere. In fact, the four major elements that make up organic matter (hydrogen, carbon, nitrogen, oxygen) are all available from air and water, both on Earth and on Mars. Therefore a significant amount of the mass that makes up plants, soil life, and the soil itself, can come from Mars.

Over time, as the soil becomes rich in soil life, the soil turns black. The deep rich, fertile black color is from the concentration of carbon in the soil, stored as organic matter, both dead and alive. This process is sometimes called natures "capture and hold" system for storing carbon, nitrogen, and other nutrients in the soil.

For example, when annual plants grow on Earth, they grow for one season during an Earth-year. In winter when they die, they leave their roots behind in the soil. The next Earth-year when new annuals grow, they use nutrients (including carbon), from dead roots stored in the soil from previous years. The dead roots serve as storage containers for carbon, nitrogen, and other nutrients. This "capture and hold" system is how nature turns degraded barren soil into productive rich dark soil, loaded with organic matter.

Figure 8.1 Example of natures "capture and hold" system.
Nutrients (carbon, nitrogen, etc) that were gathered and broken
down by previous plants are stored in the soil as organic
matter where they can be used later by new plants.
This is one of the reasons farmers use "cover crops".

The importance of carbon

Dirt to Soil
One Family's Journey into Regenerative Agriculture
by Gabe Brown
Chapter 3 Regenerative Revelations
Section: The critical role of carbon
(Page 44 in my book)
In my ongoing reading and research about soil and plants, One thing that kept coming up was the importance of carbon in the system. When I came across the website amazingcarbon.com I was fascinated. Dr. Christine Jones, a soil ecologist in Australia, developed the site to help others understand the critical role carbon plays in ecosystem function, particularly underground. Dr. Jones clearly explains how soil carbon is the key driver for much of soil health. Soil carbon is also critical to water-holding capacity. Thus, she concludes, soil carbon is the key driver for farm profit.
...
A myriad of life forms use liquid carbon as a food source. The plants, in return, benefit from the nutrients released from the soil and transferred to their roots. Consider that 95 percent of life on land resides in the soil, and you'll realize just how important this relationship is. Add to this fact that, as Dr. Jones explained on her website, "microbial activity also drives the process of soil aggregation, enhancing soil structural stability, aeration, infiltration, and water-holding capacity. All living things, above and below ground, benefit when the plant-microbe bridge is functioning effectively."

Here are some YouTube videos with Dr. Christine Jones:

Christine Jones -- Soil Carbon: From microbes to mitigation

Dr. Christine Jones - Building New Topsoil Through The Liquid Carbon Pathway

Healthy Soil's Impact on Carbon Pathways & Microbial Diversity by Dr. Christine Jones

A Soil Owner's Manual
How to Restore and Maintain Soil Health
by Jon Stika
Chapter 3 How Is Healthy Soil Supposed to Function?
Section: Nutrient Cycling
(Page 22 in my book)
Once we recognize soil organisms as the drivers of soil health, we understand that the most important element in soil nutrient cycling is not nitrogen, phosphorus, or potassium, but carbon. Carbon is the currency of the soil. It feeds the organisms that comprise the soil food web so they can fix, decompose, acquire, and cycle essential plant nutrients. Carbon enters the soil economy through plants or other photosynthesizing organisms possess chlorophyll. This is why it is important to have living plants occupy the soil as much of the time as possible; to keep the underground "herd" of soil organisms fed.

The Soul of Soil
by Grace Gershuny, Joe Smillie
Chapter 2 Understanding the Soil Ecosystem
Section: Soil Anions and Their Cycles
(Page 28 in my book)
Carbon, the major constituent of plant (and animal) tissue, is more truly the "food" consumed by plants than any mineral.

Note: Cells produce soil

I'm currently working on a book "How to Make Soil on Mars" as well as a several other proposals. I'll explain all these processes in my book at a later time. For now, the point I'm making is that a byproduct of a Cell is that it produces soil. Even though a Cell is compatible with hydroponics, I recommend using soil rather than hydroponics in a Cell.

In the post below, Louis proposed a "soil factory" on Mars. I'm not sure, but I believe it was Louis that mentioned a "soil factory" consisting of rock crushers, grinders, and so on, being used in an industrialized factory setting.

Index --> Life support systems --> Mars Soil Factory
Louis wrote:
What is the best way of providing soil for soil based agriculture on Mars?
I am of the view that a dedicated soil factory probably makes sense.

It turns out that the real "soil factory" is in the soil itself, not in a factory setting. Soil is produced by life (biology) in the soil.

On Earth, humans have changed their surroundings to better suit their needs. Other forms of life, including life in the soil, do the exact same thing. Underground life will change their surroundings (soil), to better suit their needs. All of the many, many, forms of life living in soil, as well as life above ground (including humans), together form something that is referred to as the "Soil Food Web" (SFW). All of the life in the Soil Food Web, working in harmony as a single system, is what makes soil fertile.

Soil production is dependent on the physical properties of the soil, such as soil structure, soil texture, surface area, pore space, and so on. A "soil factory" consisting of rock crushers, grinders, and so on, all in a factory setting, will not produce any soil. Biology is needed for that. But it will enhance nature to do its thing, which will result in the production of fertile soil.

The plow has sometimes been touted as one of the greatest inventions of mankind. In more recent history however, experts have come to realize the damage caused by the plow. The problem with plowing fields is that it kills life in the soil and destroys the habitat for soil life. This is why many farmers have switched to no-till farming. A no-till planter places seeds in the soil with minimum soil disturbance, so as not to disrupt the biology in the soil. No-till planters, as well as many other techniques used in regenerative agriculture, will need to be used on Mars.

A Soil Owner's Manual
How to Restore and Maintain Soil Health
by Jon Stika
Chapter 1 What is Soil Health and Why Should I Care?
Section: The Suitability of Feeding the Soil
(Page 8 in my book)
The soil factory exist in and between soil aggregates, which is often referred to as 'pore space'. Soil aggregates are the crumbs and clods of soil held together by the sticky substances and filaments of the microscopic life in the soil. The workers in the soil not only run the carbon, nitrogen, and phosphorus cycles, they build and maintain the factory itself. Tillage crushes soil aggregates, damaging the soil factory. Therefore, it would seem that the first order of business is to limit this damage as much as possible. Tillage cannot create stable soil aggregates, only break them. There is no tillage operation that directly benefits soil structure and function (Brady & Weil 2002).
Crop production without tillage benefits the soil by not disturbing it any more than necessary to accomplish the placement of seed in the soil to germinate and grow. The only soil disturbance necessary should be a function of the size of the seed that needs to the placed in the soil and the spacing of the rows to achieve a suitable stand of crop.

Last edited by Steve Stewart (2024-09-29 22:29:27)

Steve Stewart · 2023-05-06 23:24:10

Harvesting Carbon and a Martian Soil Factory (Part 2 of 2)

Hydroponics vs soil

Let me make it clear I am not against hydroponics. I feel certain hydroponics will have its place in an early Martian base. Both soil and/or hydroponics will work in the Cell I am proposing. But hydroponics has its limitations. Soil has many advantages over hydroponics. For one thing, without soil a Martian base will never be self-sustaining.

And another reason, 95% of all life that lives on land lives in the soil. (There are more microorganisms in a teaspoon of healthy soil than there are people on Earth). Higher forms of life are dependent on these smaller forms of life that live in the soil. If Mars is going to provide redundancy for life on Earth and we don't have any soil on Mars, then we'd be leaving 95% of land life behind.

Soil has three major systems at play. A chemical system, a biological system, and a physical system (soil structure, soil texture, etc, as was mentioned earlier). All three of these systems MUST be working well in order to produce healthy plants. Healthy plants are a prerequisite to producing healthy food. Healthy food is a prerequisite to a healthy crew. When all three of these systems are functioning well (the biological system, physical system, and chemical system), soil is referred to as "functional soil".

One of the problems with hydroponics is that it's pretty much a chemical system only. In order to produce healthy, nutrient dense food on Mars, plants MUST be grown in functional soil.

For the Love of Soil
Strategies to regenerate our food production systems
By Nicole Masters
Chapter 5 First There Was Light
(Page 65 in my book)
As you can see, plants do not exist in isolation. Ponder this for a moment, many plant vital functions are external to their body; they outsource essential functions to microbes that are responsible for immunity, nutrient and water availability. Their gut, kidneys and thermostat are outside of their bodies. If you consider the primary goal of soil management, is to support an optimal digestive system, it is the fungi that supply powerful gut acids, vitamins, enzymes and minerals to fuel energy and health. Can you grow plants without soil and biology? Yes. Will they be healthy, have full genomic expression and be nutrient dense? No.

Dirt:
The Erosion of Civilizations
By Dr. David R Montgomery
Chapter 10 Life Span of Civilizations
(Page 240 In my book)
Growing food hydroponically -- by pumping water and nutrients through dirt in a laboratory -- can produce far more per unit area than growing food in natural soil, but the process requires using large external inputs of nutrients and energy. This might work on small-scale, labor-intensive farms, but it cannot feed the world from large operations without huge continuous inputs of fossil fuels and nutrients mined from somewhere else.

For anyone interested in learning more about agriculture, plants, and soil, there are several books and videos I would recommend. The first book I recommend is Soil Science Simplified by Helmut Kohnke and D. P. Franzmeier. (I bought the 4th edition years ago. The 5th edition is now available)

Another author I recommend is David R. Montgomery. Books I recommend are:

Dirt: The Erosion of Civilization

The Hidden Half of Nature

Growing a Revolution

He has a new book out which I have not yet read. (The paperback version will not be available until mid-summer of this year).

What your food ate

There are also several YouTube videos with David R. Montgomery. This one is about 45 minutes long:

"A soil health revolution - keys to human civilization & health" David Montgomery - Nobel Conference 54

In this video Dr. Montgomery talks about "the simple set of principles", which are:
1) minimal soil disturbance (no-till),
2) keep the ground covered at all times (cover crops),
3) use diverse crop rotations (multicultural vs monoculture).

In the video Dr. Montgomery said:

"Agriculture is not a question of organic versus conventional. Agriculture is how to apply an understanding of soil ecology to build soil health and sustain high crop yields using far less inputs."

Another author I recommend is Gabe Brown.

Dirt to Soil

Figure 9.1 List of books recommended above
Top Left to right: Soil Science Simplified, Dirt: The Erosion of Civilization, The Hidden Half of Nature
Bottom left to right: Growing a Revolution, Dirt to Soil

Gabe Brown has several YouTube videos. This one I recommend is about an hour long.

Gabe Brown: Keys To Building a Healthy Soil

In this video Gabe Brown describes his 5 key points in building healthy soil. On Mars, we will need to follow all 5 of these key points. The 5th point is incorporating livestock. Although I don't foresee having livestock on Mars anytime soon, let's not forget that humans qualify as animals. Humans on Mars can fulfill the role Gabe Brown describes in key point 5.

Another person I recommend is Ray Archuleta. Gabe Brown mentioned Ray several times in his book "Dirt to Soil". Ray has a long list of videos on YouTube. Here is a short list I got from a quick search on YouTube.

GFE 2016 - Ray Archuletta "It Starts With the Soil"

Soil Health Principles - Ray Archuleta

Gabe Brown & Ray Archuleta share their journey into regenerative agriculture @ the MN SH Coalition!

GFE 2017 - Ray Archuleta 'Regenerating the Land'

Ray Archuleta - Regenerative Agriculture: The Butterfly Effect that will Change the World

Gabe Brown, Rick Haney, Buz Kloot, Ray Archuletta, and Dave Brandt - all in one place April 5, 2017.

Gabe Brown and Ray Archuleta are in the Netflix documentary "Kiss the Ground", narrated by Woody Harreison. The trailer for the documentary is at the following link. I've seen the documentary and highly recommend it.

Kiss the Ground - Official Movie Trailer (2020)

To reiterate, I'm working on a book about making soil on Mars. I'll address many issues in my book at a later time. For now, it's time to get back to my proposal of a Cell, which has a soil factory, in addition to ways of storing energy on Mars.

Why "Turning Mars Green" will not work

There have been many proposals about "turning Mars green" in order to terraform Mars. The thinking seems to be that if Mars were covered with vegetation, the atmosphere would somehow get thicker and end up with the right ratio of oxygen and nitrogen. The temperature would mysteriously get warmer, and radiation and UV rays would magically go away. All that foliage would somehow transform all of Mars into a "Garden of Eden" paradise, making it just like Earth. Unfortunately, that's not how things work.

If Mars were covered with some type of foliage that consumed CO2 and produced oxygen, it would make the frigid planet Mars even colder, and would cause the ultra-low air pressure of Mars to be even lower.

CO2 is a greenhouse gas. O2 is not. If all the CO2 on Mars were to be replaced with O2 it would cause Mars to get even colder. Because CO2 acts like a blanket covering Mars, holding in heat from the Suns rays. Removing that blanket would cause Mars to cool. The colder atmospheric temperatures would decrease air pressure.

Also a cubic kilometer of O2 weighs less than a cubic kilometer of CO2. This is assuming they are both at the same temperature and pressure. Let me explain:

According to Avogadro's law, a cubic km of CO2 would have the exact same number of molecules as a cubic km of O2. This is assuming both are at the same temperature and pressure. The atomic mass of O2 is 16 and the atomic mass of CO2 is 44. Therefore the cubic km of O2 would only weigh about 36% as much as the cubic km of CO2 (16/44 = 36%).

Suppose someone had a magic wand and waving it caused all the CO2 molecules in the Martian atmosphere to be replaced with O2 molecules. This would lower the air pressure on Mars to about 36% of what is was before. (Mars atmosphere is mostly CO2). Plants covering the surface would consume the CO2 in the Martian atmosphere and release O2 (assuming there is enough water on Mars to feed the plants). Therefore replacing the Martian atmosphere (CO2) with a gas that only weighs 36% as much (O2), would cause the air pressure to drop to almost a third of its original pressure.

Gabe Brown, author of the best selling book "Dirt to Soil" which I recommended reading above, has "5 principals of soil health." One of his 5 principles is "Keep armor on the soil." He is saying that farmers need to keep the ground covered with foliage at all times. Suppose a farmer has one square meter of bare soil on their farm. On a day when the air temperature is 90F (32C) the soil temperature can reach 150F (66C). This kills biology in the soil which is something you don't want to do.

When soil is covered with foliage, the energy from the Suns rays is converted into chemical energy through the process of photosynthesis (CO2 is converted into carbon compounds). If the ground is bare, then the Suns rays are converted into heat energy instead, causing the surface to overheat.

Right now all of the Suns rays being absorbed by Mars is being converted into heat. 100% of it. If Mars were to be covered with green foliage, much of that energy would no longer be converted into heat, rather it would be converted into chemical energy, through the process of photosynthesis, causing the planet to cool. Therefore "turning Mars green" by covering the surface with vegetation is the last thing we want to do. It would reverse any terraforming that had been done up to that point.

Therefore plants and people will always be living inside of a protected habitat while the surface of Mars remains mostly unchanged. There will never be a "Garden of Eden" covering the surface of Mars. Nor will there ever be humans wondering around through heavy vegetation covering the planet without any space suits -- without protection from the temperature, air pressure, UV rays, or radiation. Because Earth life will always be contained in some sort of habitat(s). For that reason I don't see any conflict between putting humans on Mars and planetary protection.

Last edited by Steve Stewart (2024-09-29 22:30:09)

Steve Stewart · 2023-05-06 23:25:15

How the Martian Atmosphere is Brought into a Cell

In Post #7 I mentioned that air from the Martian atmosphere can be pumped directly into a Cell. But there is a problem, the Martian atmosphere contains the poisonous gas carbon monoxide (CO). To solve this problem, air from the Martian atmosphere is pumped directly into the flame of a burner, or into the intake of an engine. When carbon monoxide passes through burning methane in the presence of oxygen, it will pick up an extra oxygen atom and be converted into carbon dioxide (CO2).
The reaction is as follows:

2CO + O2 ---> 2CO2

This is an exothermic reaction and is the reason why catalytic converters on automobiles get so hot. Converting carbon monoxide into carbon dioxide will give the Cell a negligible boost in heat, and might even give an engine a slight boost in power.

I refer to outside air being brought into a Cell as "Cheat". Cheat is mostly CO2, but there are other gases that come into a Cell with Cheat. The Martian atmosphere also contains 0.17% oxygen and 1.9% nitrogen. These gases are desirable to bring into a Cell from the Martian surface.

Editors Note: The exact percentages of oxygen and nitrogen given vary, as air pressure on Mars varies because of the freezing and thawing of CO2 at the poles. An article by NASA and JPL states:

The overall increase in pressure between Sol 31 and Sol 93 is the signature of the entire Martian atmosphere growing in mass as we move into springtime in the southern hemisphere. This happens because the south pole receives more and more sunlight, and carbon dioxide vaporizes off of the winter south polar cap. Each year the atmosphere grows and shrinks by about 30 percent due to this effect.

When the two gases, oxygen and nitrogen, come into a Cell as Cheat, the percentage of nitrogen in the Cell will slowly increase, and the Cell will get a small boost in oxygen. If 1% of the oxygen in a Cell can come from the surface of Mars, rather than from plants alone, then 1% more methane can be burned, resulting in 1% more heat, and 1% more pure oxygen will be produced by the Cell.

So to answer the question:

"How can nitrogen from the Martian atmosphere be brought into a base?"

How Do You Get Nitrogen Buffer Gas On Mars?
http://newmars.com/forums/viewtopic.php?id=7716

The answer is to simply pump outside air in from the Martian atmosphere into burning methane. Over time this will cause the percentage of nitrogen in a Cell to increase. No additional pumps, refrigeration devices, fractional distillation, or any other mechanical devices that consume energy are needed.

How much nitrogen comes in with Cheat?

In order to calculate the amount of nitrogen that comes in as Cheat, assume that plants are in a Cell of a certain size, such that the plants consume 96 liters of CO2 every hour (96 liters at STP). And for the sake of simplicity, assume the 96 liters of CO2 are consumed every hour of every day. And assume that the percentage of CO2 and the Martian atmosphere is exactly 96.00%. And assume exactly 100 liters (measured at STP) of outside air from the Martian atmosphere is pumped into a Cell as Cheat every hour of every day.

In this scenario, 96 liters of CO2 is brought into a Cell every hour and all of it is consumed by plants each hour, therefore the amount of CO2 in the Cell never changes. However, the percentage of other gases that are in the other 4 liters coming in, will change. The other gases that coming in with the 100 liters of Cheat are:

1.9 liters of nitrogen
1.9 liters of argon
0.17 liters of oxygen
Trace amounts of neon, krypton, and xenon.

Therefore, if the plants in a Cell consumed an Average of 96 liters per hour over the course of one Earth-week (168 hours), the amount of gases brought into a Cell as Cheat comes out to:

319.2 liters of nitrogen
319.2 liters of argon
28.6 liters of oxygen
The trace gases neon, krypton, and xenon start to accumulate.

The Earth atmosphere is nearly 80% nitrogen. The triple bond of nitrogen makes nitrogen pretty much inert at room temperature, therefore nitrogen is considered a "filler gas". Other gases, such as noble gases (inert gases), can also be used as a filler gas. The trace gases neon, krypton, and xenon, are all noble gases, and therefore can be used as filler gases in a Cell. These filler gases can be separated from the air in a Cell by using a fractional distillation machine similar to the one shown below in Figure 10.1.

Figure 10.1 Example of a fractional distillation machine

Noticed that about 98% of the gas brought into a Cell through Cheat does not need any processing of any kind. The CO2 that is brought directly into a Cell as Cheat is consumed by plants. Some of the nitrogen brought into a Cell through Cheat is consumed by plants (legumes), and the rest is used as a filler gas for the Cell. Any carbon monoxide that comes in with Cheat is converted into CO2 as it passes through burning methane in the presence of oxygen.

Only about 2% of the gases brought in as Cheat needs to be processed by fractional distillation. The processing of air from the Martian surface is done after air is brought into a Cell, not before. By doing it this way, only 2% of the air from the Martian surface needs to be ran through a fractional distillation machine, not a 100%. This saves energy, time, and wear and tear on equipment that has to be sent from Earth, which will eventually wear out.

Figure 10.2 below shows an atmospheric processing system describe on Marspedia. This plan and others, is to process ALL air from the Martian atmosphere before any of it can be used. In this proposal I am proposing only processing 2%. By processing 2% of the air rather than 100%, the fractional distillation equipment should last about 50 times longer, and use about one fitieth as much energy.

Figure 10.2 Image from Marspedia

Later in Post #14 titled "How Much Oxygen does a Cell Produce?" I'll go through the math and show that one Cell of a given size will produce about 13 cubic meters (13,000 liters) of oxygen every 24 hours. This equates to 542 liters of oxygen produced per hour (at STP). If a Cell were to consume 542 liters of CO2 per hour for one Earth-week (168 hours). The amount of nitrogen and other gases it would bring in from the Martian atmosphere in one Earth-week would add up to the following:

1,729 liters of nitrogen
1,729 liters of argon
155 liters of oxygen
The trace gases neon, krypton, and xenon start to accumulate.

The Martian

In the movie "The Martian", there is a scene in which the Martian base becomes depressurized. Below is a YouTube video of that scene:

Malfunction Scene : The Martian 2015
(1 min 42 sec)

Apparently, the Martian base had an extra supply of nitrogen and oxygen on hand to re-pressurize the living area with breathable air. The extra air, along with a tank to hold the air, would've had to of been brought from Earth.

If the Martian base had at least one Cell, an extra supply of nitrogen from Cheat and oxygen from plants could have been collected on Mars and stored. The mix of nitrogen and oxygen could have been stored as breathable air and released into the living area if needed. With the emergency supply of breathable air now depleted, both the supply of nitrogen and supply of oxygen could have been replenished by a Cell. The only thing that would be needed from Earth is the storage tank to hold the air.

How vacuum pumps work

A piston pump will not work very well pumping in air from the low air pressure from the Martian atmosphere. (There was an argument on this forum about that). Therefore a vacuum pump is used to pump in air from the Martian atmosphere. Figure 10.3 and Figure 10.4 below are examples of a vacuum pump.

Figure 10.3 Principle of operation for a vacuum pump
(Image source)

Figure 10.4 Large vacuum pump
(Image by Busch Vacuum Solutions)

YouTube Video:
Rotary Vane Operating Principles Technical Animation

Burning methane cleans the air in a Cell

The burning of methane in a Cell cleans the air. The temperature of a methane flame is 3,542 F (1,950 C). The assumption is that if something passes through a methane flame in the presence of oxygen and does not react, then it must be fairly inert.

As an example, in Post #8 I recommended using soil rather than hydroponics. A potential problem with making soil on Mars is that it will likely release gases when it first comes into contact with air and/or water. Such was of concern with Apollo 11 and lunar dust, as Buzz Aldrin described in his book "Mission to Mars".

Mission to Mars
by Buzz Aldrin
Chapter 4 Dream's of My Moon
(Page 84 in my book)
Lunar dust soiled our suits and equipment, and it had a definite oder. Like burnt charcoal, or the ashes that are in a fireplace. Especially if you sprinkled a little water on them.
Before we left Earth, some alarmists considered the lunar dust as very dangerous. In fact, pyrophoric, capable of igniting spontaneously in air. The theory was that lunar dust had been so void of contact with oxygen, as soon as we re-pressurized our lunar module cabin, it might heat up, smolder, and perhaps burst into flames. At least, that was the worry of a few. A late July fireworks display on the moon was not something anyone wanted!

It's possible that a fresh tray of soil in a Cell could vent some gases. Some of these gases might be desirable and some may not.

The Case for Mars
The Plan to Settle the Red Planet and Why We Must
by Robert Zubrin
Chapter 7 Building the Base on Mars
Section: Green Thumbs for the red Planet
(Page 214 in my book)
The oxidant that Viking may have detected in Martian soil will be no problem, as it decomposes into reduced material and free oxygen on contact with water. The warm greenhouses will be moist environments, and as the moisture circulates it will quickly cause the greenhouse soils to give off their oxygen.

Martian regolith also contains frozen CO2. It's likely that soil made on Mars will vent CO2, oxygen, and some wanted and unwanted gases. If fresh soil were to release gases in a Cell, these gases would end up passing through burning methane in the presence of oxygen. The assumption is that the gases will burn off and be reduced into something harmless, such as CO2, water, etc. Or, if it doesn't react, then it must be fairly inert. Thus the burning of methane in a Cell cleans the air, enabling various processes to take place in a Cell.

As an example, suppose a manufacturing process requires the use of an epoxy, and the epoxy releases fumes as it cures. As long as the process is done in a Cell, the fumes from the epoxy will eventually pass through burning methane in the presence of oxygen. The assumption is that the fumes will then be broken down into something harmless. The Cell could also use air filters made from mineral wool to help clean the air.

Other ways of cleaning the air

In addition to burning methane, a Cell can contain other ways to clean the air. For example, air passing through a burner (gas furnace) could include an ultra-violet light. UV lights are used in HVAC systems to purify the air. Figures 10.5 and 10.6 below show examples of UV lights used in HVAC systems.

Figure 10.5 Advertisement for an HVAC ultra-violet light

Figure 10.6 Example of an ultra-violet light in HVAC systems

Cleaning the air with plants

The Cell could also contain plants that clean the air. Here is a list of 9 plants that clean the air according to the PBS TV show "This Old House". In addition to cleaning the air, these plants will also produce oxygen and release carbon compounds into the soil that help drive the soil factory.

This Old House - 9 Clean-Air Plants for Your Home
English Ivy
Its dense foliage excels at absorbing formaldehyde—the most prevalent indoor pollutant, says Wolverton—which shows up in wood floorboard resins and synthetic carpet dyes.
Peace Lily
This year-round bloomer rids the air of the VOC benzene, a carcinogen found in paints, furniture wax, and polishes. It also sucks up acetone, which is emitted by electronics, adhesives, and certain cleaners.
Lady Palm
Easy on the eyes, this plant targets ammonia, an enemy of the respiratory system and a major ingredient in cleaners, textiles, and dyes.
Boston Fern
This fern works especially well in removing formaldehyde, which is found in some glues, as well as pressed wood products, including cabinetry, plywood paneling, and furniture. (Some studies also show it can remove toxic metals, such as mercury and arsenic, from soil.)
Snake Plant (mother-in-law's tongue)
In addition to helping lower carbon dioxide, the snake plant rids air of formaldehyde and benzene.
Golden Pothos
Like many other vines, it tackles formaldehyde, but golden pothos also targets carbon monoxide and benzene. Consider placing one in your mudroom or entryway, where car exhaust fumes heavy in formaldehyde are most likely to sneak indoors from the garage.
Wax Begonia
The wax plant is a heavy hitter in filtering out benzene and chemicals produced by toluene, a liquid found in some waxes and adhesives, according to a University of Georgia study conducted last year.
Red-Edged Dracaena
This plant will take care of gases released by xylene, trichloroethylene, and formaldehyde, which can be introduced by lacquers, varnishes, and sealers.
Spider Plant
Put a spider plant on a pedestal or in a hanging basket close to a sunlit window and you'll benefit from fewer airborne formaldehyde and benzene molecules.

Here are more lists of plants that clean the air:

12 NASA recommended air-purifying plants that you must have in your house

18 Houseplants That Clean The Air (NASA Says So)

HGTV - 20 Best Plants for Cleaning Indoor Air

Healthline - The Best Air-Purifying Plants for Your Home

Best Houseplants for Purifying Indoor Air

Burning methane, using a mineral wool filter from in-situ resources, an ultra-violet light, and plants, provide several ways of cleaning the air in a Cell. Cleaning the air serves as an Enabler to allow manufacturing processes to take place in a Cell.

Last edited by Steve Stewart (2024-09-07 15:36:29)

Steve Stewart · 2023-05-06 23:26:18

How to Build a Dehumidifier That Doesn't Have Any Moving Parts

In the description of a Cell in Post #6 I mentioned the Cell has a dehumidifier that doesn't have any moving parts. The following is a description on how such a dehumidifier can be built.

A dehumidifier works by having two sets of coils, one that gets hot (condenser) and one that gets cold (evaporator), just like an air conditioner or a refrigerator. As air passes through the dehumidifier, water condenses on the cold coil (evaporator) as shown in Figure 11.1 below.

Figure 11.1 Functional diagram of a dehumidifier

A dehumidifier can be made based on the principles of the absorption refrigerator, which does not have any moving parts. Absorption refrigeration was originally invented by Michael Faraday in 1821. Different variations of absorption refrigeration were invented over the years. Later in 1926, Albert Einstein and his former student proposed an alternate design called the "Einstein refrigerator". Wikipedia article titled Einstein refrigerator states:

"The Einstein–Szilard or Einstein refrigerator is an absorption refrigerator which has no moving parts, operates at constant pressure, and requires only a heat source to operate. It was jointly invented in 1926 by Albert Einstein and his former student Leó Szilárd, who patented it in the U.S. on November 11, 1930 (U.S. Patent 1,781,541)."

Below are some pictures I took while visiting Pioneer Village, located in Minden Nebraska (USA). This is an Icy-Ball refrigerator, which is an absorption refrigerator. Heat is applied to the copper ball on the right, after it gets hot the ball on the left gets cold.

Figure 11.2 Personal photos taken at Pioneer Village

Figure 11.3 Image from Internet of Icy-Ball refrigerator

Absorption refrigerators are still in use today. Campers use absorption refrigerators, called "RV refrigerators". Refrigerators in Campers/RV's can run on propane alone. They do not need any electricity, except for the refrigerator light.

Figure 11.4 List of RV refrigerators

The figure above is a list of RV refrigerators. The figure below lists absorption refrigerators for the home that run on natural gas (methane). All of the refrigerators shown are still in production.

Figure 11.5 List of full sized absorption refrigerators and
small absorption refrigerators for the home.

The dehumidifier that was shown in Figure 6.1 uses the absorption refrigeration method to create a hot and cold coil. Burning methane provides the heat needed to power the dehumidifier. Once manufacturing capabilities on Mars become advance enough for the smelting of iron, most, or all, of the parts in the dehumidifier can be made on Mars. The Icy-Ball refrigerator on display at Pioneer Village was built in 1925. This implies that manufacturing capabilities on Mars would only have to be equal to that of 1925 in order to build an "absorption dehumidifier".

The absorption dehumidifier will need a refrigerant. There are several types of refrigerants that can be used with absorption refrigeration. The most common type is ammonia and water. Wikipedia article titled "Absorption refrigerator" states:

"The system uses two coolants, the first of which performs evaporative cooling and is then absorbed into the second coolant; heat is needed to reset the two coolants to their initial states. The principle can also be used to air-condition buildings using the waste heat from a gas turbine or water heater. Using waste heat from a gas turbine makes the turbine very efficient because it first produces electricity, then hot water, and finally, air-conditioning—trigeneration.

Extra water is available from the "clean water" tank that was described in Post #6. On Mars, there are several sources of ammonia. Ammonia (NH3) is produced naturally from decaying organic matter, and ammonia can be extracted from human waste, particularly urine, as ammonia is part of the nitrogen cycle.

Figure 11.6 Image from Wikipedia article "nitrogen cycle".
I added the red arrow on left to show where
ammonia (NH3) is located in the nitrogen cycle.

Several ways of manufacturing ammonia have been discussed on this forum. Manufacturing ammonia requires an input of nitrogen. Nitrogen from Cheat is available from the air in a Cell. With extra water available and several sources of ammonia, a Martian base will have the resources it needs to make the refrigerant. Below is a functional diagram of the absorption refrigerator with ammonia and water as refrigerant.

Figure 11.7 Diagram of absorption refrigerator cooling cycle
with ammonia and water as the refrigerant

Although I have never heard of a problem with refrigerant from an RV refrigerator leaking, or from an absorption refrigerator in a home, we must be prepared for the unexpected. A problem with using ammonia as a refrigerant, is that the ammonia refrigerant could seep out into a Cell. This can cause serious problems as ammonia is caustic.

When ammonia burns in the presence of oxygen, it produces two things, nitrogen and water, as shown in the following equation.

4NH3 + 3O2 --> 2N2 + 6H2O

If the refrigerant were to seep out into a Cell, it would circulate around the Cell until it passed through a burner or a running engine. It would then be converted into nitrogen and water, and become part of the Cells ecosystem. Once the leak is repaired, the dehumidifier can be recharged with refrigerant made on Mars. The burning off of the leaked refrigerant is another example of how burning methane cleans the air in a Cell.

Figure 11.8 YouTube Video
IcyBall Solar Absorption Refrigeration Parabolic Mirror
By Green Power Science

Last edited by Steve Stewart (2024-08-04 00:37:41)

Steve Stewart · 2023-05-06 23:27:22

The Air Pressure Control System

Each Cell has an air compressor that compresses air from the Cell into a tank, lowering the air pressure of the Cell. When the compressed air reaches a high enough pressure, gases in the tank begin to liquify. CO2 will liquefy first before the other gases (before oxygen, nitrogen, argon and the trace gases ). Overtime, liquid CO2 will accumulate in the tank, while the other gases pass through the tank and back into the Cell.

The tank shown below in Figure 12.1 contains liquid CO2, along with the other gases, and has two lines and two valves. The red valve is connected to a line that goes to the bottom of the tank. Pure CO2 is removed by opening this valve. When the blue valve on the other line is opened it releases gases back into the Cell (or into the input of a fractional distillation machine). The gases will be mostly nitrogen, argon, and oxygen.

Over time, as the percentage of nitrogen in the Cell increases, argon can be removed. This lowers the percentage of argon and increases the percentage of nitrogen, while the percentage of oxygen and CO2 remain constant. Argon is used as a "filler gas" until more nitrogen is brought in from the Martian atmosphere.

Figure 12.1 Tank that separates CO2 from the other gases.

There are brief times when air is released back into the Cell while the compressor is running. The air returning back into the Cell does not contain any CO2 (or only trace amounts of CO2). The vent where air is being released and the inlet to the compressor are located at opposite ends of the Cell so that the vented gas does not re-enter the tank without first mixing with air in the Cell.

Having two valves on a tank to release a gas or a liquid is not a new idea and is a practice that has been used for many decades. Therefore this very simple technique of separating liquid CO2 from the air is a process that has been proven to work. Figure 12.2 below is a refrigerant tank in my garage which has two valves. The blue valve releases refrigerant gas and the red valve releases liquid refrigerant.

Figure 12.2 Refrigerant tank with two valves. Blue (gas) and red (liquid).

Monitoring the level of liquid CO2

The level of liquid CO2 in the tank is constantly monitored by the Air Pressure Control System. This can be done a couple of ways. One way is to have a float in the tank, much like a float in a car's gasoline tank that provides an output for the gas gauge. Another way is to simply weigh the tank. On Earth, scales are commonly used by A/C professionals to measure the amount of refrigerant being added or removed from an A/C system. A couple examples of refrigerant scales are shown below in Figure 12.3.

Figure 12.3 Example of refrigerant scales.

When the Air Pressure Control System detects the tank is getting full of liquid CO2, some of the liquid CO2 is released and put into storage. Therefore a byproduct of the Air Pressure Control System is that it produces pure CO2, which has many uses on Mars (more about that later in Post #13).

The carbon cycle problem

As Bryce Myer explains in the image below, humans do not exhale enough CO2 to feed themselves. One way to think of this, is to imagine one person sealed in a greenhouse with enough plants to feed that person. In that case, the individual will not breathe out enough CO2 to feed the plants. Or, if the greenhouse had just enough plants that the plants could live off of the CO2 coming from the human, there would not be enough plants to feed the human.

A source of CO2 is needed in order for humans to grow enough plants to feed themselves. Even more CO2 is needed if astronauts are growing more than just food, such as plants from all of the 4F's (Food, Fiber, Forrest, Fuel). Carbon is needed for plants, soil life, and in the production of soil.

Figure 12.4 Image from the following YouTube video by Bryce Myer at 16m 50s.
NSS Space Forum -Bryce Meyer - Farming in Space for Future Space Settlement

Fortunately, Mars has plenty of CO2 in its atmosphere. Cheat provides a method of harvesting carbon from the Martian atmosphere. As was explained in Post #8 and Post #9, CO2 is constantly being consumed by plants in the production of carbon compounds (exudates), which in turn feed soil life, and in turn produces fertile soil that is rich in carbon. Therefore Cheat is needed to replenish CO2 as it is being consumed.

Normal operation of the Air Pressure Control System

As was explained in Post #10, air from the Martian atmosphere is brought directly into a Cell as "Cheat." This air is mostly CO2. As was just stated, CO2 is needed to replenish the CO2 being consumed by plants. Bringing in air as Cheat causes the air pressure in the Cell to rise. Some of the incoming CO2 is removed by the Air Pressure Control System and some is consumed by plants. (The Air Pressure Control System holds the air pressure constant by removing CO2 from the air as needed).

In a Cell, astronauts are wearing breathing apparatus. Therefore the limit of concentration of CO2 in the air of a Cell is determined primarily by how much the plants can handle, which in turn is dependent on the type of plants being grown in the Cell, as well as a number of other factors.

At this writing, the level of CO2 in Earths atmosphere is 406 parts per million (0.041%). In the early 1950's, the level of CO2 in Earths atmosphere was closer to 300 parts per million (0.030%). Prior to the industrial revolution in the mid 1700s (prior to burning fossil fuels), the CO2 level on Earth was about 240 parts per million (0.024%). Plants can handle a level of CO2 considerably higher than this. As was mentioned in Post #7, the CO2 level on the International Space station varies from 3,000 parts per million (0.300%) to 5,000 parts per million (0.500%).

Usually the rate at which Cheat is coming in is not dependent on the rate air pressure is changing in a Cell, and it is not dependent on the rate CO2 is being consumed by plants. Rather it is dependent on how much methane is being burned at any one time.

Burning methane provides an opportunity to bring in Cheat from the Martian atmosphere. The idea is to bring in as much Cheat as possible whenever the opportunity presents itself. Therefore it would be beneficial to bring Cheat into a Cell anytime methane is being burned, regardless of air pressure. If Cheat is brought into a Cell when more air is not needed, the Air Pressure Control System will simply remove CO2 so that the air pressure does not increase.

The air pressure is held constant by removing CO2 at a faster or slower rate. One way to do this is with a variable-speed air compressor. Variable-speed air compressor have become commonplace in high efficient air conditioners/heat pumps in homes.

As air pressure in a Cell goes up, CO2 is removed at a faster rate. As air pressure goes down, CO2 is removed at a slower rate. The compressed air in the tank shown in Figure 12.1 is released back into the Cell as needed. In the short run, the percentages of gases in a Cell remain constant (ie. the percentage of CO2, nitrogen, argon, and oxygen, remain constant). In the long run, the percentages of gases that come in with Cheat will increase. (Most notably, the percentage of nitrogen and argon will increase). Trace gases (neon, krypton, xenon) will also increase over longer periods of time.

Argon is used as a filler gas when the level of nitrogen in a Cell is too low. Legumes growing in a Cell will consume nitrogen from the air while adding nitrogen to the soil. Nitrogen in the soil is then converted into organic matter (plants and soil life). This will be explained later in Post #13.

Over time, as nitrogen is added to the soil, less nitrogen from the air will be consumed by plants/soil life and the percentage of nitrogen in a Cell will gradually increase. As it does, argon can be removed from a Cell by using fractional distillation (explained later in Post #13). This keeps the percentage of other gases (primarily oxygen and CO2) at a constant level. Fractional distillation is also used to remove trace gases from the air when needed. (Trace gases: neon, krypton, xenon, can also be used as filler gases).

As mentioned, the percentage of CO2 is kept constant by consuming more or less methane. Consuming more methane will cause the level of oxygen to go down and the level of CO2 to go up. Consuming less methane will cause the level of oxygen (which is constantly being produced by plants) to increase and the level of CO2 to decrease.

In the short run, the percentage of nitrogen and any filler gases (argon and the trace gases) will remain constant. In the long run, the filler gases will accumulate and start to crowd out CO2, causing the level of CO2 to go down as the percentage of the trace gases go up. This is because the Air Pressure Control System will remove CO2 from the air as the air pressure increases.

However, the Oxygen Control System keeps the level of CO2 at a preset level by monitoring the level of CO2 and adjusting the rate at which methane is being reacted with oxygen. This causes the level of oxygen to change slightly as the filler gases build up, while the level of CO2 remains constant.

The end result is that the filler gases will crowd out oxygen and the level of CO2 will remain constant.

Graphical Description

The figures below illustrate what was just described. In Figure 12.5 below, the percentage of oxygen in the air of a Cell is 24.8%. The percentage of CO2 is 0.2%, and the percentage of filler gases is 75.0%. (The filler gases can be a mix of nitrogen argon and the trace gases) . The percentage of gases are currently in a state of equilibrium.

Figure 12.5 Percentage of gases in a Cell.

Figure 12.6 below illustrates the percentage of filler gases going up by 0.1%. This is because some of the gases that came in with Cheat are filler gases. Most notably nitrogen and argon. For this example it is assumed that these gases raised the amount of filler gases by 0.1%.

Keep in mind that plants are consuming CO2 while at the same time CO2 from the Martian atmosphere is coming in as Cheat. For this example it is assumed that plants are consuming CO2 at the same rate CO2 is being brought in as Cheat.

With the rate of CO2 coming in at the same rate it is being consumed, the percentage of gases in the Cell remain constant at a temporary point of equilibrium. I say "temporary" because the other gases in the Martian atmosphere (primarily nitrogen and argon) will begin to accumulate in the Cell. This accumulation of gases is what causes the percentage of filler gases to increase by 0.1%.

When the percentage of filler gases goes up by 0.1%, it increases the air pressure in the Cell. As was previous stated, the Air Pressure Control System will remove CO2 from the air to compensate for the increase in air pressure. Therefore when the percentage of filler gases goes up by 0.1%, the level of CO2 will drop by 0.1%, as shown in Figure 12.6 below.

Figure 12.6 Percentage of filler gases going up by 0.1% causes CO2 level to drop by 0.1%.

With the CO2 level dropping the Oxygen Control System will detect a change in the percentage of CO2 in the air. It will notice that the CO2 level is below the preset value of 0.2% and will respond by reacting more methane with oxygen in order to bring the CO2 level back up to the preset value. This can be done by simply turning up the size of the methane flame(s).

When the Oxygen Control System reacts more methane with oxygen, it causes the level of CO2 to increase by 0.1% to the setting of 0.2%. This causes the oxygen level to drop by 0.1%, down from 24.8% to 24.7% as shown in Figure 12.7 below. The new equilibrium point is now 24.7% oxygen, 75.1% filler gases, and the CO2 level stays at the preset level of 0.2%.

Notice when the percentage of filler gases increase by 0.1%, the level of oxygen in the Cell ends up decreasing by 0.1% while the CO2 level remains fixed at 0.2%.

Figure 12.7 When the CO2 level goes up by 0.1% the oxygen level goes down by 0.1%.

Figure 12.8 below shows an example of the net result when the percentage of filler gases increase. The percentage of filler gases start out at 70%, and over time goes up to 75%. As the percentage of filler gases drift upward, the percentage of oxygen drifts downward as was just described. The percentage of oxygen will drop from 29.8% to 24.8%. In the meantime the percentage of CO2 remains fixed at 0.2%. The percentage of CO2 might fluctuate a bit while the percentages of other gases are changing, but will remain close to the preset value of 0.2%.

Notice the the Oxygen Control System can set the oxygen level by removing or adding filler gas(es) to the Cell.

Figure 12.8 Net result of increasing filler gases.

As was just shown, as the filler gas percentage goes up, the percentage of oxygen goes down. The opposite happens when a filler gas is removed from a Cell. For example, suppose a Cell has the percentage of gases that was shown in Figure 12.7. Oxygen = 24.7%, CO2 = 0.2%, Filler gases = 75.1%.

If argon were removed from the Cell and it caused the percentage of filler gases to go down by 0.1%. The percentage of filler gases would drop from 75.1% to 75.0%. As a result, the percentage of oxygen would then increase from 24.7% to 24.8%. This would be the new equilibrium point.

If argon and the trace gases where removed from a Cell each time the percentage of filler gases increased, over time it will cause the filler gases to be mostly nitrogen, making the air in a Cell more and more similar to that of Earth. This shows how a Cell is able to harvest nitrogen and other gases from the Martian atmosphere.

Summary

So as a general rule, the percentage of oxygen and percentage of CO2 in a Cell is controlled by reacting more, or less, methane with oxygen. This can be done by adjusting the size of the methane flame (or flames). The percentage of nitrogen and filler gases will increase over time as Cheat is brought into a Cell. The trace gases are removed as needed by fractional distillation. It is assumed that the Martian base will have a set of storage tanks to hold the different gases. The gases can then be used at a later time to bring new Cells online, as more Cells are built. The Cell is designed to be as simple as possible, so that more Cells can be built using mostly in-situ resources (ISRU).

The Air Pressure Control System can increase or decrease the air pressure in a Cell by adding air, or removing CO2 from a Cell. And the Oxygen Control System keeps the level of CO2 constant, causing the level of oxygen to go down as the level of filler gases go up. And the level of oxygen goes up whenever the level of filler gases goes down. This is how the Air Pressure Control System works most of the time. However there are exceptions. There could be times when removing CO2 at a faster or slower rate is not enough to keep up with a rapid change in air pressure.

Less common operation of the Air Pressure Control System

If the air pressure is dropping too fast, such that stopping the removal of air from the Cell isn't enough to keep up with the drop in air pressure. Then the air from the tank that was shown in Figure 12.1 can be released back into the Cell. If a Cells air pressure is still too low after the tank has been depleted, nitrogen and/or argon that have been removed and stored can be released back into the Cell. Pure oxygen that is stored can also be released back into the Cell as long as the oxygen level doesn't get too high.

If pressure in a Cell is rising too fast, incoming Cheat can be slowed down or stopped completely. Cells have plumbing and wiring connecting Cells to each other. If stopping incoming Cheat is not enough to stop the rise in air pressure, air pipes that connect several Cells to each other, can be opened to allow air from the higher pressured Cell to flow into the other Cells.

Dumping air into the other Cells, rather then releasing it back out into the Martian atmosphere, prevents highly sought after gases, such as nitrogen and oxygen, from being lost. It also prevents water in the form of humidity from being lost.

Each Cell has its own Air Pressure Control System and its own Oxygen Control System. If a Martian base has three Cells, then there will be three Air Pressure Control Systems, one in each Cell, each operating independently. This is needed for redundancy.

For example, if the Air Pressure Control System in Cell#2 stops working, a valve on a pipe that goes to Cell#1 can be opened, causing Cell#1 and Cell#2 to have the same air pressure. At this point the Air Pressure Control System in Cell#1 is controlling the air pressure in both Cell#1 and Cell#2.

If this is too much for Cell#1 to handle, the pipe between Cell#2 and Cell#3 can be opened. In this scenario, two Air Pressure Control Systems are controlling the air pressure in three Cells .

Last edited by Steve Stewart (2024-09-08 00:35:24)

Steve Stewart · 2023-05-06 23:28:26

Martian Resources Out of Thin Air

Harvesting nitrogen from the air

When Cheat is brought into a Cell, the incoming CO2 is either consumed or removed. This causes the percentage of other gases that came in as Cheat to increase. Other than CO2, the most predominant gases being brought in from the Martian atmosphere are nitrogen, argon, and oxygen.

Oxygen ends up being used in the Methane-Oxygen Cycle. Each liter of oxygen brought into a Cell as Cheat will result in one more liter of pure oxygen being produced by the Cell. Nitrogen brought into a Cell is consumed by plants and soil life, as nitrogen is a major component of organic matter (roots, stems, leaves, as well as microbes).

Nitrogen is brought into a Cell through Cheat. Once a high enough percentage of nitrogen is in the air of a Cell, it can be harvested from the air by growing legumes. Legumes are plants such as soybeans, peas, clover, peanuts, etc, that establish a relationship with nitrogen-fixing bacteria in the soil. Nitrogen-fixing bacteria convert nitrogen in the air (N2) into a form that plants can use. Plants can only use two forms of nitrogen: ammonia (NH4+) and nitrate (NO3-). Both of these forms are unstable (reactive) and do not last long in the soil.

After plants consume the nitrogen they need they use the "capture and hold" system to store nitrogen in the form of organic matter (explained in Post #8). This inadvertently stores nitrogen in a stable (less reactive) form. When old plants die and their seeds sprout new roots, nitrogen in a stable form remains stored in the soil as organic matter. Not only as dead roots, but also as amino acids, proteins, DNA, plant cells, living and dead microbes, and so on. (The mass of bacterial cells can contain up to 60% nitrogen). The stored organic matter, composed entirely of Essential Elements, is completely useless to plants. The problem is that all of this organic matter is in a form that plants cannot use.

This is where microbes come in. Once new plants establish a relationship with microbes in the soil by feeding them exudates (Post #8), the microbes go to work breaking down organic matter into a form that plants can use. The microbes convert nitrogen from a stable form (organic matter) into a form that plants can use (ammonium and nitrate). Nitrogen is quickly consumed in this highly reactive state. Very little nitrogen is lost, as the nitrogen cycle is extremely efficient and not lossy. Nitrogen and other nutrients in the soil are recycled over and over again in this way, indefinitely, in a never ending loop.

In order for the process to work the soil must contain the right microbes. Soil on Mars will be sterile, so all forms of soil life, including nitrogen-fixing bacteria, must be brought from Earth. Legume seeds can be bought with a coating that contains nitrogen-fixing bacteria. The end result is nitrogen from Cheat is stored as organic matter enriching the soil and the rest of the nitrogen is needed to improve air quality in a Cell. (The goal is to have air in a Cell be nearly 80% nitrogen - same as Earth).

Uses for other gases

The most predominant gas left over after nitrogen and oxygen are used is argon, followed by several trace gases. Over a period of time, argon and the trace gases will begin to accumulate in a Cell. This is a way of enriching these gases, making it easier to extract them from the air. Trace gases from the surface of Mars include neon, krypton, and xenon. These gases could be removed from a Cell using some type of air separation, such as fractional distillation. Shown below is an example of a fractional distillation machine.

Figure 13.1 Example of a fractional distillation machine

There are many uses for argon on Mars. Argon is used in arc welding and cutting of metals, where it is used as an inert gas shield. It is also used as a protective atmosphere for growing silicon and germanium crystals, and in the production of solar panels. Argon-39 has been used for ground water dating. Argon is a poorer conductor of heat than ordinary air, and has been used between panes of glass to provide better insulation.

The trace gas neon could be used in the production of neon lights. Neon gas has other applications. Neon could be combined with helium to make helium-neon lasers. Helium-neon lasers are used in barcode scanners, tool alignment, non-contact measuring and monitoring systems, blood analysis, particle counting and food sorting. Liquid neon is used as a cryogenic refrigerant. Neon can also be used to make high voltage indicators.

Krypton gas is used in some types of photographic flashes used in high speed photography. Xenon is also used in photographic flashes. Xenon is used in high pressure arc lamps for motion picture projection, and in high pressure arc lamps to produce ultraviolet light. Xenon is used in instruments for radiation detection, such as neutron and X-ray counters and bubble chambers. It is used in medicine as a general anesthetic, and in medical imaging. Ion thrusters use inert gases, especially xenon, for propellant.

Uses for CO2

The Air Pressure Control System removes CO2 from the air in a Cell as was explained in Post #12. Once CO2 has been liquefied, it is kept in storage tanks because pure CO2 has many useful applications on Mars. For example, pure CO2 can be used to pressurize a new Cell, as developed Cells are used to bring new Cells on-line. CO2 can be used to re-pressurize a Cell that has lost pressure, because of a malfunction.

CO2 can be used in fire extinguishers, as fire is of major concern in space flight, and will be of major concern in a Martian base. CO2 can be bubbled in water to stimulate the growth of algae. On Mars, algae will play an important role in the converting of non-organic material into organic matter, as well as a source of oxygen.

On Earth, CO2 is used by dry cleaners. On Mars, CO2 could be used to clean clothes in order to conserve water. CO2 can be used as a refrigerant. On Earth, CO2 refrigerant is known as R-744 and has been used as an environmentally friendly refrigerant in cars. CO2 could be used as a blowing agent. A blowing agent is a substance that has a low boiling point. Blowing agents are needed to make substances like styrofoam, which is an excellent insulator.

On Earth, CFC’s and HCFC’s were used for blowing agents. On Mars, liquid CO2 could be used. Metal Carbonates and Bicarbonates are prepared using CO2. CO2 can be used to prevent oxidation. CO2 can be used to make dry ice which can be used to keep things cool, or to cool things quickly. On Earth, CO2 is often used in carbonated beverages. Imagine being on Mars drinking a carbonated strawberry soda. Unlike Earth, it does not contain any aspartame, Sucralose, or a flame retardant, because it is made entirely from natural ingredients. These are just a few of the applications of CO2 on Mars.

Last edited by Steve Stewart (2024-08-04 00:40:50)

Steve Stewart · 2023-05-06 23:29:32

How much oxygen does a Cell produce?

For these calculations I'm going to use the oxygen output of grass as a baseline. I'm using grass because data on grass is readily available. The following calculations are made under the conditions that everything is at standard temperature and pressure (STP). I'll also use an Earth-day as a baseline. This is because the oxygen output of grass, and other references I'm using, are all given in Earth-days. The web-site BOS SOD Farms, Inc states:

(Last sentence under section "Cleans our Air")
A turf area 50' x 50' produces enough oxygen to meet the everyday needs of a family of four and each acre of grass produces enough oxygen for 64 people a day.

If 1 acre of grass provides enough oxygen for 64 people, and knowing that there are 43,560 square feet in one acre, I conclude that 680.625 square feet of grass will produce enough oxygen for 1 person.

(43,560 sq ft/acre) / (O2 for 64 people/acre)
= (680.625 sq ft / O2 for one person)

The next question is:

"How much oxygen does the average person use in one day?"

The web-site Shareware.com states:

"So, as far as how much air is actually used, human beings take in about 550 liters of pure oxygen per day."

This YouTube video also states that one person consumes 550 liters of oxygen a day.

How Much Oxygen Does a Person Consume in a Day?
BrainStuff - HowStuffWorks

Assuming that the average person uses 550 liters of pure oxygen per Earth-day, and that 680.625 square feet of grass produces enough oxygen for one person per Earth-day. I conclude that 680.625 square feet of grass produces 550 liters of pure oxygen per Earth-day. I also conclude that one square foot of grass will produce 0.808081 liters of pure O2 per Earth-day.

(550 Liters) / (680.625 square feet)
= (0.808081 Liters) / (1 square foot)

In order to calculate how much oxygen a Cell produces, I need to define dimensions for that Cell. Cells can of be various shapes and sizes. For the sake of calculations, I'll use the following dimensions for a Cell. (These dimensions are arbitrary).

Figure 14.1 Floor plan of a Cell

The floor plan shown is for a Cell that is 35' wide and 100' long (10.7 meters x 30.5 meters).
(Dimensions shown are inside dimensions. Thickness of walls are not relevant for these calculations).
The Cell has a stack of 6 trays on each side of an aisle, spaced 2' apart vertically (0.61 meters).
The trays are 90' long and 15' wide (27.4 meters x 4.6 meters).
The Cell contains trays of grass growing in soil.
The aisle down the middle is 5' wide (1.5 meter).
The ceiling is flat and is 12' high (3.7 meters high).
Below are floor plans for the Cell with English and Metric dimensions.

Figure 14.2 Floor plan of a Cell with dimensions (English units)

Figure 14.3 Floor plan of a Cell with dimensions (Metric units)

The empty space on the end is a staging area.
It is 10' x 35', providing 350 square feet of open space.
(3 meters x 10.7 meters, providing 32.5 square meters of space).

The square footage of the Cell is 3,500 square feet (325 square meters).

The volume of the Cell is 42,000 cubic feet (1,189 cubic meters).

3,500 square feet x 12 feet (ceiling height) = 42,000 cubic feet

325 square meters x 3.658 meters (ceiling height) = 1,189 cubic meters

Below is a 3D render of the Cell described above.
The ceiling and two walls are not shown.
The dehumidifier, water tank, burner/engine, CE5, etc, are not shown.

Figure 14.4 3D cutaway view of the Cell described above
I added the computer desk and chair for size comparison.
(I'm using home design software to create this image).

Trays are 15' x 90' which provides 1,350 square feet of plants per tray. (125.4 Square meters).
This Cell has a total of 12 trays (6 on each side of the aisle) providing a total of 16,200 square feet of plants (1,505 square meters).
If this Cell were growing grass and each square foot of grass produced 0.808081 liters of oxygen, then the Cell would produce 13,091 liters of pure oxygen per Earth-day.

(16,200 square feet of grass) x (0.808081 Liters of 02 / square feet of grass)
= 13,091 Liters of O2

13,091 liters equates to 462.3 cubic feet, 17.1 cubic yards, and 13.1 cubic meters of pure oxygen per Earth-day. (Reminder: Numbers given are at STP).
This is almost as much oxygen as what 24 people would use in one Earth-day.

(24 people) x (550 Liters / person)
= 13,200 Liters of O2 required per Earth-day

A Cell provides a more favorable environment than what plants have growing in a field on Earth. The plants in a Cell will always receive the optimum amount of water. (No droughts or floods), and they can receive as much light as they can handle (in a hybrid greenhouse, or with artificial light). Plants can usually receive a maximum of 12 to 18 hours of light per Earth-day, depending on the plant.

A Martian day is a bit longer than an Earth-day (24.617 hours as opposed to 23.933 hours). Therefore the amount of grass shown growing under ideal conditions should produce a considerably more than 13,091 liters of oxygen in a Martian day (Sol), everyday of the year. And because a Martian day is longer, and because astronauts will be physically active on Mars (working and exercising), they will likely use considerably more than 550 liters of oxygen in a day (Sol).

Most of the oxygen produced by a Cell is created by plants. Some of the oxygen produced by a Cell is "stolen" from the Martian atmosphere in the form of Cheat. (Cheat was explained in Post #10). Some of this oxygen is used for aerobic composting, which produces soil. (Fertile soil is mostly oxygen).

Soil Science Simplified
by Helmut Kohnke and D.P. Franzmeier
Chap 4 Chemical Properties of Soils
Section: Chemical Composition of Soils
(Page 27 in my book)
Five elements account for 95% of the weight of soil. Oxygen alone represents half of its weight, and because of its large size and relatively small weight, oxygen also makes up more than 95% of the entire volume of soil. The other elements take up so little space that they fit between the oxygen atoms.

Some oxygen is used by processes that take place in a Cell, as a Cell is an Enabler that makes many processes possible. Cells make processes possible by creating an environment suitable for processes to take place, as well as create resources needed for those processes.

For example, a Cell can provide a comfortable environment for the manufacturing of textiles, while at the same time it is able to grow the raw materials needed for textiles, such as cotton, hemp, and flax. The oxygen that these plants produce can be used in a CE5 to produce electricity to run textile machines, while at the same time generate heat for both the workspace and the growing area. If the manufacturing of textiles requires mechanical energy, the Cell can provide the oxygen needed to run an engine that runs on methane, as was mentioned earlier. Assuming left overs from textile manufacturing are organic matter, the waste can be recycled into compost, using the composter located in a Cell. Compost is a highly desirable type of fertilizer.

Weeds
Guardians of the soil
By Joseph A. Coannouer
Chapter 9 Weeds in the Compost
(Page 80 in my book)
In the small town garden, compost can really prove its worth. For all types of small gardens compost is beyond question the most economical as well as the most desirable fertilizer. This is because the Howard-type Compost makes it possible for the gardener to get an amazingly high production of quality vegetables from a small plot.

Sir Albert Howard

The work of Sir Albert Howard

The amount of oxygen removed from a Cell each day, must to be equal to the amount of oxygen produced by the Cell. Otherwise the percentage of oxygen in the Cell will either get too high or too low. The total amount of oxygen produced by a Cell is equal the amount of oxygen created by plants, plus the amount of oxygen brought in from the Martian atmosphere in the form of Cheat, minus the amount of oxygen used by composting and other activities taking place in a Cell. The equation is as follows:

(O2 from Plants + O2 from the Martian atmosphere)
- (O2 used in composting and other activities)
- - - - - - - - - - - - - - - - - - - - - -
= Amount of oxygen produced by a Cell.

Figure 14.5 Amount of oxygen produced by a Cell.

As was shown, the Cell described above creates an estimated 13,091 liters of oxygen from plants everyday. Let's assume (hypothetically) that 109 liters of oxygen a day is brought in the Cell from Cheat. (109 liters is 0.8% of the 13,091 liters that a Cell produces). Per the equation above, the total amount of oxygen produced by the Cell would be 13,200 liters per day.

13,091 Liters + 109 Liters = 13,200 Liters

And let's assume, once again hypothetically, that aerobic composting consumes 200 liters of oxygen per day. (This equates to 1.5% of the total oxygen produced by a Cell). Per the equation above, the Cell would have a net gain of 13,000 liters of oxygen a day. This means that there are 13,000 liters of oxygen in a Cell that needs to be removed each and every day.

How much methane does a Cell require?

As was explained in Post #7, oxygen is removed from a Cell by reacting oxygen with methane. If a Cell produces 13,000 liters of oxygen a day, the next question is:

"How much methane is needed to remove 13,000 liters of oxygen from a Cell?"

Per Avogadro's law, one mole of methane will occupy the same amount of space as one mole of oxygen, or any other gas. The concept is illustrated by the image below.

Figure 14.6 Cubic meter of methane (left) and a cubic meter of oxygen (right)

In Figure 14.6 above, the reddish colored cube on the left represents one cubic meter of methane. The yellow cube on the right represents one cubic meter of oxygen. Per Avogadro's law, the number of methane molecules (CH4) that are in the cubic meter on the left, has the exact same number of molecules as the cubic meter of oxygen (O2) on the right. This is always true, regardless of the temperature and pressure. As long as both cubes are at the same temperature and pressure, and both cubes are the same size, they will always contain the exact same number of molecules.

As shown in the equation below, when methane reacts with oxygen, each molecule of methane reacts with two molecules of oxygen.

CH4 + 2O2 --> CO2 + 2H2O

Another way to look at it, one cubic meter of methane requires two cubic meters of oxygen to react with the methane. The ratio of their volumes is always 2 to 1 as long as both the methane and oxygen are at the same temperature and pressure.

This means in order to remove a cubic meter of oxygen from the air in a Cell, one half of a cubic meter of methane is required. In the hypothetical case of the Cell described above, 13,000 liters (13 cubic meters) of oxygen are created every day. In order to remove 13,000 liters of oxygen from the air, half that amount of methane (6,500 liters) are required to react with the oxygen. (6.5 cubic meters of methane are required to remove 13 cubic meters of pure oxygen from the Cell everyday).

Figure 14.7 One cubic meter of methane reacts with two cubic meters of oxygen.
The reaction will create water and one cubic meter of CO2.

A minimum of 6,500 liters of methane are required to react with oxygen in order to remove 13,000 liters of oxygen from the air. It's perfectly acceptable for more than 6,500 liters of methane to be used. Some of the pure oxygen removed from a Cell can be safely released back into the Cell in order to hold the percentage of oxygen constant. As long as at least 6,500 liters of methane is reacted with oxygen, it will remove 13,000 liters of oxygen each day, keeping the percentage of oxygen constant.

It should be noted that the percentage of oxygen in a Cell is adjustable. The Oxygen Control System is able to keep the percentage of oxygen plus CO2 constant. It does this by monitoring the level of CO2 in a Cell. More, or less, methane is reacted with oxygen to keep the CO2 level at a preset value. In doing so, the oxygen level stays at a stable level.

If the CO2 level is too low, more methane is reacted with oxygen. This causes the level of CO2 to bump up a bit while the level of oxygen goes down by an equal amount. If the level of CO2 is getting too high, less methane is reacted with oxygen, causing the level of oxygen to increase, due to oxygen produced by plants, while the level of CO2 goes down from being consumed by plants.

Therefore the sum of the percentage of oxygen and CO2 remain at a fairly constant level at any one time. The rest of the air in a Cell is a filler gas (nitrogen, argon, and the trace gases). Over time, as more of the filler gases are brought into a Cell through Cheat, the percentage of filler gases creep upward. As the percentage of filler gases slowly increases, the percentage of oxygen slowly goes down, while the level of CO2 remains at a preset level.

Removing any of the filler gases (argon and/or trace gases) will cause the percentage of the filler gases to creep downward as the level of oxygen creeps up. All the gases in a Cell are always at a level that is adequate for plants, but not necessarily suitable for humans. This is why humans must wear breathing apparatus when working in a Cell. The conditions of the air in a Cell, pressure, temperature, humidity, and percentages of gases in the air, is determined by what is best/adequate for the plants.

If the methane were burned, how much heat would be produced?

Another question is:

"If a Cell were to burn 6,500 liters of methane in a gas furnace, how much heat is produced?"

There are 36,303 BTU's in one cubic meter of methane at STP.
Therefore burning 6,500 liters (6.5 cubic meters) of methane will result in nearly 236,000 BTU's of heat.

(6.5 cubic meters) x (36,303 BTU's / cubic meter)
= 235,970 BTU's

Figure 14.8 Diagram of a burner in a Cell.
If methane is burned to remove 13,000 liters of oxygen from a Cell,
it will create nearly 236,000 BTU's of heat per day.

If all the methane were used in a CE5, how much electricity and heat would be produced?

As was shown above, 6,500 liters of methane creates 235,970 BTU's of heat. If we assume a CE5 is 50% efficient, then the amount of heat produced would be cut in half. Which comes out to about 118,000 BTU's of heat.

235,970 BTU's / 2 = 117,985 BTU's

An equal amount of electricity would be produced. There are 0.293071 Watt-Hours in one BTU. This much energy is the equivalent of about 34.6 kW of electricity.

(117,985 BTU's) x (0.293071 Watt-Hours / one BTU)
= 34,578 Watt-Hours of electricity
= 34.578 kW of electricity

Therefore if 6.5 cubic meters of methane and 13 cubic meters of oxygen were to be ran through a CE5, it would create an estimated 34.6 kW of electricity and nearly 118,000 BTU's of heat.

Figure 14.9 Diagram of a CE5 in a Cell.
If a CE5 were used to remove 13,000 liters of oxygen from a Cell,
it would generate an estimated 34.6 kW of electricity,
and produce nearly 118,000 BTU's of heat per day.

As a reminder, the burner (gas furnace) and CE5 are not making energy. They are simply recovering energy that was stored as methane and oxygen. The stored chemical energy comes from the Sabatier reactor, which consumes energy. At least 69.2 kW of electricity is used, plus any losses due to inefficiencies in the system. (69.2 kW is the amount of energy in 6,500 liters of methane).

For example, if the Sabatier reactor is 50% efficient, it would consume 138.4 kW of electricity to produce 6,500 liters of methane. (Two times 69.2 kW). Whether or not the "wasted" heat from the Sabatier reactor is used is dependent on where the reactor is located. If the reactor can be located somewhere that some or most of this "wasted" heat can be used, then the Sabatier reactor can be considered much more efficient, in some cases 100% efficient.

Both methane and oxygen are stored in storage tanks. Storage allows the methane to be consumed at a faster or slower rate than it is being produced at any one time. A certain amount of electricity needs to be allocated to the Sabatier reactor in addition to extra electricity available whenever all the energy from a power source is not being used. (As was explained in Post #2). Whenever extra electricity is available, it is used by the Sabatier reactor to store the extra energy, so it is not lost. As the available amount of extra electrical energy changes, the amount of methane being produced at any one time changes.

The amount of oxygen produced by plants at any one time also changes. Plants produce more oxygen during the day when light is available, then they do at night without light. Therefore methane storage is needed because the rate methane is being produced at any given time rarely matches the rate oxygen is being produced. If a methane-oxygen powered lander(s) is/are used to send supplies on a one way trip to Mars, the tanks in those landers could be repurposed to store methane and oxygen for a Cell.

Oxygen is added to the tank(s) everyday, while at the same time it is being removed from storage and is being used somewhere else on the Martian base. (Such as oxygen for astronauts to breath). The amount of oxygen added to oxygen storage tank(s) each day is always equal to the amount of oxygen produced by the Cell that day. (Per equation in Figure 14.5).

Note: The amount of oxygen added to storage is always equal to the amount produced by a Cell

As stated, it's acceptable to react more methane in a Cell than there is oxygen produced by that Cell. Stored pure oxygen can be safely released back into the Cell if more oxygen is needed. The ratio of oxygen reacting with methane is always 2 to 1, as was explained earlier (Figure 14.7). If more than 6,500 liters of methane is used to remove 13,000 liters of oxygen, then stored oxygen will be safely released back into the Cell to react with the extra methane.

As mentioned earlier, Cells contain oxygen sensors that detect the percentage of oxygen in a Cell. The Oxygen Control System will release the right amount of pure oxygen from storage, so that the percentage of oxygen in the Cell remains constant. Reacting 7,000 liters of methane in a Cell when only 6,500 liters are needed will result in 1,000 liters of pure oxygen being released back into the Cell.

When the Sabatier reactor produces more methane than is needed, it also produces more oxygen to go with it. When the Sabatier reactor produces 6,500 liters of methane, it produces 13,000 liters of oxygen. When the reactor produces 7,000 liters of methane, it produces 14,000 liters of oxygen.

Therefore if 6,500 liters of methane is needed and an extra 500 liters of methane is produced, an extra 1,000 liters of oxygen is also produced. This extra 1,000 liters of pure oxygen will end up being safely released back into the Cell, so that the percentage of oxygen in the Cell remains constant. (The Cell will have the right amount of oxygen necessary to react with 7,000 liters of methane -- 14,000 liters. 13,000 liters produced by the Cell and 1,000 liters from storage). The end result is illustrated below in figure 14.10.

Figure 14.10 A Cell with 13,000 liters of oxygen to be removed.
From the Cells prospective:
7,000 liters of methane reacts with 14,000 liters of oxygen.
13,000 liters of oxygen is produced by the Cell and 1,000 liters from storage.
From the Sabatier reactors perspective:
7,000 liters of methane is produced
14,000 liters of oxygen is produced

The Cell shown in figure 14.10 has 13,000 liters of oxygen that needs to be removed. 7,000 liters of methane are reacted with oxygen in the the Cell. The Oxygen Control System will release pure oxygen into the Cell as needed to hold the percent of oxygen constant. The Cell will react 14,000 liters of oxygen with 7,000 liters of methane. Of the 14,000 liters of oxygen reacted, 13,000 liters was produced by the Cell and 1,000 liters was released into the Cell by the Oxygen Control System, keeping the percent of oxygen in the Cell constant.

When the Sabatier reactor produces 7,000 liters of methane, it also produces 14,000 liters of oxygen. Of the 14,000 liters generated by the reactor, 1,000 of those liters are released back into the Cell, leaving the remaining 13,000 liters added to oxygen storage.

Note:
The amount of oxygen being added to storage is always equal to the amount of oxygen being produced by the Cell.

When the Sabatier reactor creates 7,000 liters of methane it will consume a minimum of 74.5 kW of electricity. (74.5 kW is the amount of energy in 7,000 liters of methane). If the Sabatier reactor is 50% efficient, it will consume 149 kW of electricity. (Two times 74.5 kW).

Another thing to note

Because the majority of oxygen comes from plants, methane alone can be stored for backup power without the need of storing a matching amount of oxygen. This is true as long as the plants are alive and Cells are producing oxygen.

Last edited by Steve Stewart (2024-08-09 01:29:57)

Steve Stewart · 2023-05-06 23:30:35

Metrics in a Cell

Every bit of space in a growing area for plants (Cell) will come at a high price. I haven't done the math, but a growing area for plants will likely cost a few million US dollars for every cubic meter of space. A living area for humans will cost even more. It is imperative that we get the most productivity out of every bit of space. In order to get the most productivity from a Cell, there are a number of metrics to consider:

Metric #1:
Oxygen created per unit of volume

One metric that could be used, is the amount of oxygen produced per unit of volume. The question is:

"On average, how much oxygen is produced per cubic meter of space in a Cell?"

The Cell that was just shown in Post #14 creates an estimated 13,000 liters of oxygen per Earth-day. The volume of the Cell is 42,000 cubic feet (1,189 cubic meters). If this Cell contained 12 trays of grass as was used in the calculations, the Cell would produce 0.31 liters of oxygen per cubic foot of space and 10.93 liters of oxygen per cubic meter of space per day.

(13,000 Liters O2 produced) / (42,000 cubic feet)
= 0.3095238 Liters O2 produced) / cubic foot

(13,000 Liters O2 produced) / (1,189 cubic meters)
= 10.9335576 Liters O2 produced / cubic meter

Metric #2:
Ratio of area of plants to area of building

The Cell that was described in the previous section (Post #14) has 3,500 square feet of space (325 square meters). The Cell had 12 trays of plants, providing a total area of 16,200 square feet of plants. (1,505 square meters).

Trays are 90' long and 15' wide:
90' x 15' = 1,350 square feet per tray
(12 trays) x (1,350 square feet / one tray)
= 16,200 square feet (1,505 square meters)

The ratio of plant area (16,200 square feet) to building area (3,500 square feet) is 4.63.

(16,200 square feet of plants) / (3,500 square feet of building)
= 4.63

Ratio's stay the same regardless of units.

(1,505 square meters of plants) / (325 square meters of building)
= 4.63

Figure 15.1 Cell with 12 trays of plants spaced 2' apart vertically
This configuration provides an area for plants that is 4.63 times larger than the area of the building.

If the Cell had half as many trays so as to allow for taller plants. The ratio of growing area for plants to the area of the building would be cut in half. The Cell would have an area for plants that is 2.314 times the area of the building.

Figure 15.2 Cell with 6 trays of plants spaced 4' apart vertically reduces the ratio by one half.

Metric #3:
Percentage of soil per unit of volume

The Cell that was shown in Figure 15.1 has a total of 16,200 square feet of plants.
If the trays were 1' deep, the Cell would contain 16,200 cubic feet of soil (459 cubic meters).
The volume of the Cell is 42,000 cubic feet (1,189 cubic meters).

Therefore the ratio of the volume of soil to the volume of the Cell would be 0.386.
(38.6% of the volume of a Cell is soil).
This means that there is 0.386 cubic feet of soil per cubic foot of space in the Cell.
This equates to 667 cubic inches of soil for every cubic foot of space in the Cell.

(16,200 cubic feet of soil) / (42,000 cubic feet of space)
= 0.386 cubic feet of soil / cubic foot of space

= (0.386 cubic feet of soil) x (1,728 cubic inches / cubic foot)
= 667 cubic inches of soil / cubic foot of space

Ratio's stay the same regardless of units. There is 0.386 of a cubic meter of soil for every cubic meter of space in the Cell.

(459 cubic meters of soil) / (1,189 cubic meters of space)
= 0.386

If the trays in the Cell were 4" deep instead of 12" deep (1 foot deep), then the amount of soil in the Cell would be one third as much. The ratio of soil to volume of the Cell comes out to 0.129 cubic feet of soil per cubic foot of space in a Cell. Which equates to 222.2 cubic inches of soil per cubic foot of space in a Cell.

(16,200 cubic feet of soil) / 3 = 5,400 cubic feet of soil

(5,400 cubic feet of soil) / (42,000 cubic feet of space)
= 0.129 cubic feet of soil / cubic foot of space

= (0.129 cubic feet of soil) x (1,728 cubic inches / cubic foot)
= 222.2 cubic inches of soil / cubic foot of space

In this scenario, 12.9% of the space in the Cell is soil. The ratio is the same for metric units. (0.129 of a cubic meter of soil per cubic meter of space in a Cell).

If the trays in the Cell were 8" deep, the amount of soil would be twice as much as it would be with 4" deep trays. The ratio of soil to volume of the Cell comes out to 0.257 cubic feet of soil per cubic foot of space in a Cell. Which equates to 444.3 cubic inches of soil per cubic foot of space in a Cell. In this scenario, 25.7% of the space in the Cell is soil. The ratio is the same for metric units.

(5,400 cubic feet of soil) x 2 = 10,800 cubic feet of soil

(10,800 cubic feet of soil) / (42,000 cubic feet of space)
= 0.257 cubic feet of soil / cubic foot of space

= (0.257 cubic feet of soil) x (1,728 cubic inches / cubic foot)
= 444.3 cubic inches of soil / cubic foot of space

If the Cell had half as many trays that were spaced 4' apart vertically, to make room for taller plants, the amount of soil in the Cell would be cut in half.

Figure 15.3 Cell with 6 trays of plants spaced 4' apart vertically.

For a Cell with 6 trays:
For trays that are 4" deep, the ratio is 0.0645 (6.45% of the space in a Cell is soil)
For trays that are 8" deep, the ratio is 0.1290 (12.9% of the space in a Cell is soil)
For trays that are 12" deep, the ratio is 0.1930 (19.3% of the space in a Cell is soil)

A few things worth noting. A configuration with fewer trays spaced farther apart makes room for taller plants. (As shown in Figure 15.2 above). This configuration with half as many trays also has half the area for plants, and half as much soil. As was mentioned in Post #8, the soil factory exist in the soil itself, not in an industrialized factory setting. The more soil that is in a Cell, the larger the soil factory, and the more soil the Cell is producing.

The more soil that is in a Cell, the less room there is for plants. So there is a tradeoff between how much soil is in a Cell (the size of the soil factory), and how much room is available for plants. Changing the number of trays in a Cell also changes the area of plants in a Cell. (Changes the acres/hectares of soybeans, or acres/hectares of wheat, etc, that are in a Cell, or group of Cells).

Metric #4:
Amount of food produced per unit of volume

This is a tricky one, because on Earth we often think of food production in terms of bushels per acre. For Mars, we often think in terms of the number of acres (or hectares) required to feed a small crew.

If a farm produces a certain number of bushels of wheat per acre, or a certain number of bushels of soybeans per acre, or corn, etc, we tend to ask ourselves:

"How long can someone on Mars live on an acre of wheat, or an acre of soybeans, corn, etc?"

The problem is that an acre (or hectare) is a two dimensional number. When talking about a growing area on Mars, we need to be thinking in three dimensions.

In the Cell that was shown in Figure 15.1, trays were stacked vertically 2' apart, resulting in the Cell having 12 trays. This would would probably provide just enough space to grow soybeans. However, this is not enough space to grow wheat. In order to grow wheat, the space between the trays would need to be doubled. Trays would need to be stack 4' apart vertically.

If the vertical spacing between trays were doubled, then the Cell would have half as many trays, as was shown in Figure 15.3. The total growing area for plants would be cut in half, as was mentioned in Metric #2. The growing area would be reduced from 16,200 square feet to 8,100 square feet. (Reduced from 1,505 square meters to 753 square meters)

So if we are talking about how much food a Cell on Mars can produce, perhaps the question should be:

"How much food can be produced with 16,200 square feet (1,505 square meters) of soybeans and how does that compare to 8,100 square feet (753 square meters) of wheat?"

If corn were grown in the Cell shown, it probably would not have any trays at all. The corn would extend from the floor to the ceiling. If corn were planted everywhere except the staging area (no aisle provided in this case), it would have a growing area that is 3,150 square feet (293 square meters). The question would then be:

"How long could one person live on 3,150 square feet (293 square meters) of corn, and how does that compare with 8,100 square feet (753 square meters) of wheat, or 16,200 square feet (1,505 square meters) of soybeans?"

I think the answer is that corn does not have very good metrics.

Metric #5:
ACH - Air Changes per Hour

The metric "Air changes per hour" is a term that is commonly used in building codes (commercial and residential). When referring to the size of a bathroom exhaust fan needed for a bathroom, this is the ratio of the volume of the bathroom to the CFM (cubic feet per minute) of the exhaust fan.

Air changes per hour

In a Cell on Mars, ACH could refer to the CFM of air going through a burner or engine, compared to the volume of the Cell. In Post #10 I mentioned that burning methane in a Cell cleans the air. I mentioned an example of using epoxy, and that fumes from the epoxy would be burned off by burning methane in a Cell. The question is:

"How fast would the epoxy fumes, or any impurities in the air, burn off in a Cell?".

The answer is dependent on the air changes per hour (ACH) of the Cell. Suppose the air moved through a burner (gas furnace) at a rate of 50 CFM (typical rating for a small bathroom exhaust fan). The volume of the Cell is 42,000 cubic feet. In this case, it would take 14 hours for all the air in a Cell to pass through the burner one time.

42,000 cubic feet / (50 cubic feet / minute)
= 840 minutes

840 minutes / (60 minutes / 1 hour)
= 14 hours

(Time is the same for metric units)

If the air moved through a burner (gas furnace) at a rate of 100 CFM (typical rating for a large bathroom exhaust fan). It would take half as much time (7 hours) for all the air in the Cell to pass through the burner one time.

However not all of the volume of a Cell is air. As was shown in metric #3, some of the volume of a Cell is occupied by soil. In the case of 12 trays, and the trays being 8" deep, it was shown that 25.7% of the space in the Cell is soil. This leaves 74.3% of the space (31,206 cubic feet) to be occupied by air.

42,000 cubic feet x (100% - 25.7% of space is soil)
= 42,000 cubic feet x (74.3% of space remains for air)
= 31,206 cubic feet of air

In this case, it would take 10.4 hours for all the air in a Cell to pass through the burner one time with a CFM of 50. And half that time (5.2 hours) with a CFM of 100.

31,206 cubic feet of air / (50 cubic feet / minute)
= 624 minutes

624 minutes / (60 minutes / 1 hour)
= 10.4 hours

Plants in a Cell also displace air. So do the trays themselves, and any equipment located in a a Cell. Such as a dehumidifier, engine, CE5, water tanks, composter, etc. As water tanks change from empty to full, the water in the tank will displace air in a Cell, causing the volume of air in a Cell to decrease. A decrease in the volume of air shortens the ACH time.

If the Cell had trays with 4" of soil instead of 8", there would be more air and less soil, therefore the ACH would be longer and the soil factory would be smaller. If the Cell had trays with 12" (1 foot) of soil instead of 8", there would be less air and more soil, resulting in an ACH that is shorter.

The ACH metric is also dependent on how much of the methane is ran through a burner/engine, and how much of it is ran through a CE5. A CE5 does not burn methane, and therefore does not burn off impurities in the air. The ACH for a CE5 to burn off impurities is zero. (However the CE5 does have an ACH for removing oxygen from the air). When more methane is ran through a CE5, less methane is available to be ran through a burner/engine. This causes the Cells ACH for removing impurities from the air to be longer.

Conclusion to metrics

There are a number of other metrics that could be used. One metric that could be used is the number of calories produced per unit of volume (calories per cubic meter). However not only do we need to make sure the astronauts get enough calories per day, we also need to make sure they get the right amount of nutrients each day, and the right type of nutrients. Therefore another metric could be the amount of nutrition produce per unit of volume. (Nutrition produced per cubic meter of growing space).

Another concern is the amount of energy used for growing plants, and the amount of energy used to keep the growing area warm. Therefore another metric that could be used is the amount of light (energy) required per volume (Watts per cubic meter).

These metrics could be combined with calories/nutrition to create a metric of calories produce per amount of energy used (Watts per calorie, or calories per Watt). Or nutrition produced per amount of energy used, for a given volume.

There also needs to be a metric to keep track of the amount of water used to grow plants. One of the prices paid for growing plants and making soil is that plants and soil consume water. Both plants and soil contain hydrocarbons. The hydrogen in these hydrocarbons come from water.

Therefore one metric could be the amount of water used per cubic meter of growing space (Liters per cubic meter, or liters used per cubic meter per unit of time). Or the amount of water used per number of calories produced (calories per Liter, per unit of time), or water used per amount of nutrition produce. There are many things to consider. This list is just a brief introduction to a few metrics. I'm sure there are many more metrics that need to be considered on Mars.

One of the problems with using lava tubes or caves on Mars, is that they probably will not have very good metrics. This is because their geometric shape does not provide efficient use of space. Still, they would be helpful because they eliminate the need of having to move large amounts of rocks and regolith to build an underground Cell(s). Inflatables could be used in lava tubes and/or caves and organized in such a way that they result in good metrics.

Last edited by Steve Stewart (2024-10-05 04:45:49)

Steve Stewart · 2023-05-06 23:31:41

Summary

Review of energy storage

Extra electrical energy can be stored as methane and oxygen. Methane can be burned in the presence of oxygen in an engine or in a burner (gas furnace) located in in a Cell. Burning methane provides a way of removing oxygen from the air and purifying water without consuming any additional energy (Post #7). Burning methane also enables the ability of bringing in air from the Martian atmosphere (Cheat Post #10). The advantage of a CE5 is that it produces the most electricity and least amount of heat. The downside to the CE5, is that is does not burn methane and therefore does not enable Cheat.

There is a work around for this. An electrically heated catalytic converter could be used to bring in Cheat while it is being mixed with are from the Cell. The catalytic converter would convert incoming carbon monoxide (CO) into CO2, as does burning methane. The problem with this approach is that the heated catalytic converter consumes electricity. The reason for using a CE5 in the first place is to get the most electricity from methane and oxygen. The heated catalytic converter would consume some of the highly sought after electricity.

Other ways of storing energy

In addition to the Methane-Oxygen Cycle, there are other ways of storing energy on Mars. One way to store energy is to use batteries. If the batteries were located in a Cell, inefficiencies in the batteries would result in heat. As was the case with a burner, engine, or CE5, any extra heat will help warm the Cell. As long as the extra heat is needed, all of these processes can be considered 100% efficient.

Another way to store electrical energy is to use electrolysis in a Cell. Electrolysis creates hydrogen and oxygen which can be ran through the fuel cell that is in the CE5. This method of storing energy can be used to separate oxygen from the air. A fuel cell does not require an input of pure oxygen. The pure oxygen from electrolysis can be put into storage. Oxygen removed from the air by the fuel cell replenishes the pure oxygen that was stored. This method of storing energy not only separates oxygen from the air, it also purifies water.

Electrolysis is not 100% efficient and fuel cells are not 100% efficient. Any inefficiencies in these processes will result in heat. As is the case with a burner, engine, CE5, and batteries, as long as these processes are located in a Cell, the extra heat helps to warm the Cell. As long as the extra heat is needed, these processes of storing energy can be considered 100% efficient. Storing energy with electrolysis and running it through the fuel cell in a CE5 has the same disadvantage as the CE5. Electrolysis does not burn anything and therefore does not enable Cheat.

I think it is well known that most of the weight of water is in the oxygen. Hydrogen could be brought from Earth and ran through the CE5's fuel cell. A small amount of hydrogen brought from Earth and sent through a fuel cell would created a large amount of water. (The oxygen is produced by plants). Therefore anytime the Martian base is in need of water, hydrogen could be brought from Earth and ran through the fuel cell that is in the CE5. This is an efficient way to give a Martian base a boost in water and it would give the base a boost in power for as long as the hydrogen lasts. When the hydrogen tank brought from Earth is empty, it can be repurposed, as a Cell will need several storage tanks to hold different types of gases (Post #13).

Another option would be to send methane instead of hydrogen from Earth. Methane can be ran directly through a CE5 and it has the advantage of being less volatile than hydrogen. Methane has the disadvantage of having more mass per unit of water created. Methane, like hydrogen, would give the base a boost in water, and would give the base a boost in energy for as long as the methane lasts.

If a lander sent to Mars used methane and oxygen for fuel. Any left over methane in the fuel tanks could be ran through the CE5. Any left over oxygen could be ran through the fuel cell, or sent to the pure oxygen storage, or safely released into a Cell.

Types of plants

On Earth, types of plants are sometimes categorized into one of the 4F's, food, fiber, forrest, and fuel. On Mars, the "food" category could be defined as any plant that the astronauts can eat. The "fiber" category could be defined as any type of plant that can be grown for the production of fabrics, such as cotton, hemp, and flax. Flax could be classified as "Fiber" (linen), or it could be classified as "Food" (flaxseed), or both. Fuel is any type of plant that could be grown for fuel. Plants grown to make plastics could also be in this category. Or, if plastics are used to make fabrics (such as polyester), they could be in the category "fiber". Some plants could be used for either food or fuel. These plants could either be classified as "food", or "fuel", or both. Forrest includes any plant that is grown for the production of wood, such as bamboo.

Composting on Mars

As was mentioned in Post #6, Cells have composters that are used to recycle organic matter. It's possible for aerobic composting to have a small area at the core that does not receive enough oxygen. If this occurs, small areas could become anaerobic (composting without oxygen). This is why a compost pile needs to be turned periodically (aerated).

Anaerobic composting produces methane gas. It's possible that a small amount of methane could seep from a composter due to tiny portions of the compost being anaerobic. There needs to be a system in place that removes this compost-methane from a Cell, otherwise it will accumulate over time, and eventually could create a fire hazard or even cause an explosion.

As was mentioned in Post #10, burning methane in a Cell cleans the air. Therefore any methane resulting from composting will be burned off in a Cell. How fast it burns off is dependent on the air changes per hour (ACH) of the Cell. (Post #15 metric#5). The CO2 and water produced from the burning off of compost-methane will become part of the Cells ecosystem. Anaerobic composting also produces hydrogen sulfide (H2S). Hydrogen sulfide is the stuff that smells like rotten eggs and is sometimes referred to as "sewer gas". Hydrogen sulfide, like methane, is flammable and will burn off in a Cell.

Figure 16.1 Example of a composter that was shown in Post #6

Composting enables recycling human waste

On Mars, human waste can and should be recycled back into the soil. The Ancient Maya's recycled their waste back into their soil for 10,000 years. Apparently the Maya's realized a long time ago that what comes from the soil must be returned to the soil. The Maya's recycled their waste back into the soil by using it on plants that were not in the "food" category. (Waste was recycled back into fiber, forrest, or fuel).

The Netflix documentary "Kiss the Ground" (mentioned in Post #9) shows the recycling of human waste with organic matter (straw), and then composting it back into soil. This same method (thermophilic composting) could be used on Mars. Composting kills pathogens, making it safe to use as fertilizer, as English botanist Sir Albert Howard figured out a long time ago.

The Hidden Half of Nature
The microbial roots of life and health
by David R Montgomery and Anne Bikle
Chapter 5 War on the Soil
Section: Microbial Wizardry
(Page 78 in my book)
While his foes sowed doubt and fear, Howard continued to conduct field trials. He reported on an experiment in which three acres of fungus-decimated tomatoes were removed and composted. Later the compost was applied back to the same field, which produced an excellent crop, free of fungal wilt. Similar trials conducted for other crops with other diseases proved that pathogens didn't survive composting. In his view the pervasive fears about composting were unfounded, plain and simple.

On Mars, human waste could be thermophilically composted with organic matter and then used as fertilizer on plants that are not in the food category. Recycling human waste worked for the Maya's for ten millenniums and it will work on Mars.

Facebook video (2 min 45 sec)
The Poop Has to Stay in the Loop! (Kiss the Ground Movie)

YouTube video (1 min 30 sec)
Standing Rock- Patricia Arquette & Compost Toilets

Should the poop stay in the loop?

Patricia Arquette of givelove.org

This video was recently on "The Henry Ford’s Innovation Nation" (3 min 41 sec)
Regenerative Agriculture | The Henry Ford’s Innovation Nation

Wikipedia Article Titled Thermophilic composting states:
The key advantage of thermophilic composting is that the high temperatures kill diseases. Human feces composted by worms is not safe to use on food-plants, but several months of thermophilic composting will render it quite harmless. All the organisms that cause human diseases are adapted to live around human body temperature. Higher temperatures kill them. Compost that stays at 50°C (122°F) for 24 hours will be safe to use to grow food. A temperature of 46°C (115°F) will kill pathogens within a week. 62°C (143.6°F) will kill pathogens in one hour.

Even though composting kills pathogens and the composted waste is not used on plants grown for food, there still needs to be a system in place that defends against pathogens in the soil. Although plants cannot growl, bite, scratch, or run away and hide, they are far from being defenseless. Their defenses are strongest when they are grown in functional soil (functional soil was describe in Post #9).

In Post #9 I mentioned a YouTube video by Gabe Brown (Gabe Brown: Keys To Building a Healthy Soil). At 2 minutes and 40 seconds into the video, Gabe Brown talks about mycorrhizal fungi. He explains how mycorrhizal fungi protects plants from pathogens (and nematodes).

The Hidden Half of Nature
The microbial roots of life and health
by David R Montgomery and Anne Bikle
Chapter 5 War on the Soil
Section: Microbial Wizardry
(Page 96 in my book)
Scientist have now empirically and experimentally confirmed Hiltner's conclusions. In a classic experiment, replicated many times over, researchers grow plants in two types of soil. They sterilize one soil to kill all the microbes and they leave the other soil unsterilized. Then they introduced a known pathogen to each type of soil. Plants growing in the sterilized soil succumb to the pathogen while the plants growing in unsterilized soil do fine. That disease suppression results from microbial action is further demonstrated in another way. Sterilizing soil destroys its disease suppression, and on the flip side, mixing sterile soil with a tenth to as little as a thousandth of its volume with microbial-rich soil confers disease suppression.
As Hiltner intuited, the mechanisms responsible for disease suppressive soils are linked to communities of microbes. Modern science is confirming that microbe-plant relationships are not one sided affairs in which pests and pathogens call the shots. It turns out that when beneficial microbes are present in the soil near roots they send messages to plants that lead to an immune-like response called induced systematic resistance.

In Gabe Brown's video he shows that arbuscular mycorrhizal fungi (AMF) protect their host plants from pathogens. Gabe Brown then lists ways of increasing mycorrhizal fungi in the soil, which are 1) Reduce/Eliminate chemical use 2) Reduce/Eliminate tillage 3) Reduce/Eliminate synthetic fertilizers 4) Keep living plant cover on the soil for as long as possible. These four steps will need to be followed on Mars.

Figure 16.2 Screen capture at 2 minutes 45 seconds into Gabe Browns video

The Hidden Half of Nature
The microbial roots of life and health
by David R Montgomery and Anne Bikle
Chapter 5 War on the Soil
Section: The Power of Food
(Page 100 in my book)
Plants are far from defenseless and vulnerable victims waiting around for pathogens to do them in. If, that is, the rhizosphere remains well populated with life that either benefits the plant or does no harm. In this case, pathogens have little chance of crossing the moat-like rhizosphere and breaching the botanical castle wall.

Closing the loop

If the system isn't closed loop, any Essential Elements removed from the soil will need to be replenished. (Essential Elements are elements such as nitrogen, carbon, phosphorus, potassium, and so on). As an example, if cotton is grown to make clothing on Mars, then the elements (atoms) in cotton are not being returned to the soil. Therefore the Essential Elements contained in cotton will need to be replenished. The University of Missouri Extension states:

"A cotton fiber consists primarily of cellulose, which is comprised of hydrogen, oxygen and carbon. These elements form the backbone for every molecule and plant part."

If cotton is grown on Mars for clothing, the Essential Elements hydrogen, oxygen and carbon will need to be replenished. Hydrogen and oxygen can be replenished from water. Carbon and oxygen can be replenished with CO2 from the Martian atmosphere.

This is why human waste must be recycled back into the soil. If human waste is not recycled, whatever Essential Elements are contained in the waste, such as phosphorus, potassium, calcium, chlorine, sodium, magnesium, iodine, sulfur, etc, these elements will need to be replenished. Unlike the most predominant Essential Elements, these elements are not available from air and water. They must come from the soil.

Harvest rotation

Unlike Earth which has four seasons, plants in a Cell are grown year round. I recommend staggering the time in which plants are harvested and replanted. As an example, suppose wheat is harvested and replanted every 120 days. Rather than harvesting all the wheat once every 120 days, I recommend harvesting one sixth of the wheat every 20 days. (In a Cell that has 6 trays, one tray could be harvested every 20 days).

If food were harvested on Mars every 120 days, then a 120 days worth of food would have to be stored, which occupies valuable space. Doing a "rotating harvest" evens out the output of food, alleviating the need of having to store a large amount of food at one time.

Figure 16.3 Cell with 6 trays of plants spaced 4' apart vertically.

As an example, suppose the trays shown in Figure 16.3 were used to grow wheat. Assuming it takes 120 days for the wheat to grow from seed to harvest, one tray of wheat could be harvested and replanted every 20 days. Tray 1 could be harvested and replanted on day 20. On day 40, tray 2 could be harvested and replanted. On day 60, tray 3, on day 80 tray 4. Tray 5 and 6 on day 100 and 120 respectively, then the cycle repeats. Different varieties of wheat and grain crops have different growing cycles. White fonio for example, has one of the fastest growing cycles. (I'm using spring wheat as an example. It's growing cycle is typically 120 days).

A "rotating harvest" would also even out the oxygen output of the Cell. Plants produce more oxygen as they mature and produce the least amount of oxygen right after planting. If a second Cell were built and all 12 trays in the two Cells were planted with spring wheat, one tray could be harvested every 10 days. If the two Cells shown in Figure 16.4 below were connected together to form one "Dual-Cell", allowing the two Cells to exchange air, the oxygen created per unit of volume of the Cells (Post #15 metric#1) would be more consistent from one day to the next.

Figure 16.4 Example of a "Dual-Cell" with a total of 12 trays.
"Harvest rotation" keeps the food and oxygen output more consistent.

Grain crops on Mars

In Gabe Browns video that I mentioned in Post #9 (Gabe Brown: Keys To Building a Healthy Soil), Gabe Brown shows a picture of oats underseeded with three types of clover: Berseem clover, Crimson clover, and Persian clover. As mentioned in Post #13, clover is a legume that adds nitrogen to the soil. Once soil is functioning (Post #9), growing clover with oats provides the oats with all the nitrogen they need. No nitrogen fertilizer is needed. This reduces inputs, which conserves precious resources such as energy and labor. Oats are a grain crop, as is wheat, barley, rye, and a number of other plants. This technique shown by Gabe Brown will work on any grain crop grown on Mars.

Figure 16.5 Screen capture at 16 minutes 5 seconds into Gabe Browns video

Features of a Cell

A Cell has many useful features. A Cell provides a way of purifying water without using any additional energy (Post #5). A Cell uses plants to produce oxygen from CO2 and water from Mars. The Cell is then able to remove that oxygen from air without using any additional energy (Post #7). The oxygen is then available for use elsewhere in the Martian base.

A Cell reduces several forms of waste. As an example, a Cell provides a way of recovering excess electricity from what would have been considered total waste, with 100% efficiency (Post #4). A Cell makes use of impurities in dirty water, which could be considered waste. If the impurities contain Essential Elements, such as calcium, sodium, chorine, phosphorus, potassium, etc, this "waste" feeds the plants and help drive the soil factory (Post #8).

Nitrogen and oxygen that accumulate in a Cell from Cheat are put to good use by a Cell. Oxygen that comes in with Cheat increases the amount of oxygen a Cell produces (Post #14). Nitrogen increases the air quality in a Cell, feeds the plants and help drive the soil factory. As was explained in Post #13, other gases in the Martian atmosphere that come in with Cheat have many uses on Mars.

The International Space Station has a carbon dioxide removal system called "CDRA". Space station astronauts can rejuvenate the CDRA by baking it while exposing it to space, releasing the captured CO2 into space. By allowing the CDRA's to be reused, it reduces the amount of supplies that have to be sent to the station.

YouTube Video (37 sec)
Carbon Dioxide Removal on the Station

On Mars, CDRA's could be used in living areas and in Mars vehicles. The CDRA's could be baked in a Cell, which would release the CO2 into the Cell where it becomes part of the Cells ecosystem. Some of the CO2 ends up being consumed by plants. The CO2 is used by plants to make carbon compounds, which help drive the soil factory (Post #8 and Post #9). Some of the released CO2 from the CDRA's ends up being used by the Sabatier reactor, and some is removed by the Air Pressure Control System (Post #12) and is stored. As mentioned in Post #13, CO2 has many uses on Mars.

Rejuvenating the CDRA's reduces the amount of supplies that have to be sent to Mars. Baking the CDRA's in a Cell is an efficient use of heat as well. The heat used to bake the CDRA's will eventually dissipate throughout the Cell, helping to warm the Cell. Unlike the International Space Station, the heat used to bake CDRA's is not wasted by being lost to space.

Bathrooms with composting toilets could be located in a Cell. Cooking meals, which tends to put impurities into the air, could be done in a Cell. Frying foods, which would normally be unheard of in a Martian base, could be done in a Cell, as Cells are an Enabler that allow various processes to take place in a Cell.

Mars is a cold place and a Martian base (and Cells) will need to be heated. A potential problem with a Martian base is that it could be too cold due to a lack of heat. However, another potential problem is that a Cell could get too hot, particularly when manufacturing processes are taking place in a Cell. One way to prevent a Cell, or group of Cells, from getting too hot is to simply add more space.

As an example, Figure 16.4 above showed an example of a "Dual Cell". Suppose the Cells were well insulated, and the combined oxygen output of these two Cells caused so much methane to be reacted with oxygen that the Cells got too hot. One way to prevent two Cells from getting too hot is to simply build a third Cell and leave it empty, allowing air to circulate so that heat is dissipated throughout the three Cells. An example is shown below in figure 16.6.

Figure 16.6 Cell in middle has heated Cells on both sides, therefore it needs little heat.
The middle Cell prevents the three Cells from getting too hot.
I refer to the Cell in the middle as being Discretionary Space.

The two Cells on the outside are full of plants. The Cell in the middle starts out as empty space. I refer to this empty space as "Discretionary Space". As the name implies, astronauts can use this space at their discretion for whatever they need.

For example, a living area could be built in this space, giving the occupants more room. (They might be able to have their own room rather than having to share a room). If a living area were built on one end of the building, it would have double air-lock doors that open into the Cell. This is different than habitats that open to the Martian surface (Martian atmosphere). If the doors were to malfunction, as they did in the movie "The Martian" (mentioned in Post #10), nitrogen from the living area would not be lost. It would simply be "lost" into the surrounding Cell where it would either be used or recovered.

Or the Discretionary Space could be used for various processes, as was just described. Or it could have some combination of a living area, a place for processes, and provide space for more plants, which would produce more oxygen, and more soil, and more food. These processes can take place in a Cell because the Methane-Oxygen Cycle is constantly cleaning the air.

A Cell is compatible with many other proposals, including the Moon

A Cell is compatible with most any (practical) proposed habitat. As an example, a Cell is compatible with the proposal "Ice House" mentioned in Leonard David's book "Mars:".

Mars:
by Leonard David
Chapter 6 Marsland
(Page 242 and 243 in my book)
As we look into the future on Mars, our imaginations take off in many directions. This habitation design, called Ice House, includes inflatable windows infused with radiation-shielding gas attached to walls made with native ice.

Mars Ice House is the winning proposal for NASA's 2015 Centennial Challenge for a 3d-Printed Habitat on Mars.

Figure 16.7 Another inside view of the proposed "Ice House"

A Cell is also compatible with the proposal shown below. It was on display at the Royal Observatory Greenwich in London, in November of 2016. Stephen Petranek, author of "How we'll live on Mars", was on hand to talk about the habitat.

Figure 16.8 Images are from YouTube videos listed below

YouTube video (1 min 43 sec)
National Geographic looks at life on Mars with London model home

YouTube video (2 min 56 sec)
Is this what we could be living in on Mars?

YouTube video (2 min 1 sec)
Mars expert Stephen Petranek explains Martian home construction - Daily Mail

TED Talk by Stephen Petranek (17 min 14 sec)
Your kids might live on Mars. Here's how they'll survive

A Cell is compatible with most every Mars habitat proposal I have seen. It's even compatible with the Moon. If a Cell were to be built on the Moon, it would provide the lunar base with a way of storing energy efficiently, a source of oxygen, a soil factory, as well as Discretionary Space where additional living area's can be built and space for manufacturing processes to take place. Once one Cell is built, it will provide some of the resources needed to build additional Cells.

Additional Cells provide more resources, such as more space for manufacturing on the Moon, more plants means more oxygen, more food, more raw material (cotton, hemp, flax, bamboo, etc), more soil production, more living space, and so on. However the Moon does not have an atmosphere, therefore nitrogen and a source of CO2 would need to be provided on the Moon. The Moon could serve as a test bed for building Cells on Mars.

There is much more to a Cell than what I have described. I have purposely left out a lot of details in order for this proposal to be simpler and not so long. Many of the descriptions in this proposal are over simplified. I plan to write more at a later time. If this is your first time reading through this you may want to read it again. It makes more sense when reading it a second time. Thanks for reading.

-Steve Stewart

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THE END

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Link to this proposal:
http://newmars.com/forums/viewtopic.php?id=10501

tags
#spacesettlement #SpaceX #marsexploration #MarsSociety #Mars

Last edited by Steve Stewart (2024-10-05 04:46:58)

tahanson43206 · 2023-05-07 06:43:49

For Steve Steward re new topic and posts!

Thank you ** very ** much for choosing NewMars forum of the Mars Society to publish your important work!

I will ask SpaceNut to contact Mars Society to request a system backup at the earliest opportunity.

Your entire publication can be distributed via a single URL to the top post of the topic.

Any NewMars member who would like to help with publicity may forward the URL to Steve's topic to news papers in the area, if any still exist, and to such other media as may be available.

The URL for distribution of this work is: http://newmars.com/forums/viewtopic.php?id=10501

(th)

Steve Stewart · 2023-05-07 11:31:54

Tahanson,
Thanks for your kind comments. Is there any way I could get this published in the Mars Society Papers section? Maybe someone could ask Mr. Burk on my behalf. The proposal has 16 "posts". I made one (.rtf) file for each post. I then did a "copy and paste" from each file for each post. If Mars Society is willing to add this proposal to their papers section, I'd be glad convert the 16 files it into one (big) PDF file.

The only problem is that the proposal is rather long. I'm guessing it would be around 90 to 95 pages in PDF format. I think the papers in the Mars Society papers section are usually 20 pages or less. I'd be deeply honored if the Mars Society could make an exception for my proposal. I can't really make it any shorter. As mentioned in the proposal, I'm presenting several different ideas (proposals) that are all dependent on each other. If I split it out into separate proposals, each wouldn't make much sense without the others.

Another thing I could do is split the proposal into different parts (PDF files) that are about 20 pages each. I'm guessing it would be about 4 or 5 PDF files, each being about 20 pages. File 1 could be "Part 1 of 5", file 2 would be "Part 2 of 5", and so on. I'd be happy to provide several (smaller) PDF files if the Mars Society is willing to post them in their papers section. Let me know if there is anything I can do to get it posted in the papers sections.

The Mars Society Papers are at this link:
http://marspapers.org/#/papers

kbd512 · 2023-05-07 20:41:23

Steve Stewart,

Do you have per-person mass estimates for the equipment required for this sort of all-in-one life support / power storage / power production / food production system?

The volume, power input / output, and performance metrics are great, but as you know, total system mass drives everything else.

Can some of the major parts, or at least the wear components or whatever parts tend to fail most often, be sourced from local materials or at least fabricated locally if something breaks?

Ideally, we want a resilient solution that can tolerate some failures.

Is this system something that can be maintained by someone with appropriate technical training?

A lot of complex systems are maintained and repaired by people who may not have substantial general science education, but they do have a significant amount of tightly focused technical knowledge and training intended to make them specialists when it comes to the handful of systems they work on. We would need operator / technician training courses intended to teach basic operation theory, all the equipment-specifics related to the types of equipment required, practical hands-on training, followed by a demonstration of skills in a mock operational environment.

Steve Stewart · 2023-05-08 11:10:15

SpaceNut #19,
Thanks for your comments. I do remember the thread "Mars Water regolith soils 1 foot depth only" now that you mentioned it. Yes, much of what I mentioned has been discussed somewhere on this forum. Take your time reading it. I tried to post as much information and links as possible. I know I'm asking a lot to have people read all this. Some of the videos I listed are pretty long too. I'm honored for anyone willing to spend the time going through all this. Hopefully there is something here that will help on the many other topics on this forum. Feel free to ask any question you have on this thread. Even if it's a long time from now.

Steve Stewart · 2023-05-08 11:23:44

Kbd512 #20,
Thanks for your comments, I'll need to answer each of your questions one at a time. Your questions are in bold below.

Do you have per-person mass estimates for the equipment required for this sort of all-in-one life support / power storage / power production / food production system?

What I have spelled out in this proposal is essentially an introduction to what I call a "Cell". I then showed how the Cell can be used to store energy efficiently, which reduces waste, and I pointed out that the Cell also has a soil factory.

My proposal is that we build one Cell, and then use that Cell to provide some of the resources needed to build a second Cell. Once we have several Cells at one location, (which could be called a "Martian base" as Dr Johnson described and I quoted in post#2), that group of Cells can then be used to build more Cells that are a small distance away from the first "Martian base". We then build another group of Cells at that location, and continue to build and spread out on Mars.

More Cells have more resources and therefore have the ability to build more Cells with less shipments from Earth. My philosophy is to build one Cell on Mars with a minimal number of people first, then figure out how to minimize the demand for mass sent from Earth, power production and storage, food production and so on. Figuring out these things on a small "base" of a few people will reduce the amount of mass that has to be sent to Mars in the long run. Later, as the base expands to hold more people, we'll be a lot smarter and won't have to send as much mass to Mars. I can't speak for Dr GW Johnson, but I think that is the point he was trying to make in post#2 above.

Now, to answer your question about "per-person mass estimates" and equipment that would need to be sent to Mars. That is dependent on the type of building in which a Cell resides. So the answer to your question is no, I have not done any per person mass estimates because those are dependent on too many other factors.

The Cell I've described is purposely designed to be ambiguous, so that it is compatible with most any other proposal. In order to come up with estimates on the mass required to be sent to Mars, it would have to be tied to one type of building or habitat. Or tied to one proposal of a Martian base. I don't want to tie my proposal of a Cell to any one design/proposal. I'd rather leave the definition of a Cell ambiguous, so that it is compatible with other ideas/proposals. For anyone who has an idea of a building or Martian habitat, I'd encourage them to use my proposal of a Cell in their design, and then they can come up with their own estimates for mass sent to Mars, life support, power usage and storage, food production, and so on.

The volume, power input / output, and performance metrics are great, but as you know, total system mass drives everything else.

When you're talking about "total system mass" I assume you referring to the amount of mass that is sent to Mars. If so, it brings us to the next question:

Can some of the major parts, or at least the wear components or whatever parts tend to fail most often, be sourced from local materials or at least fabricated locally if something breaks?

Yes, that is correct. The object of the game is to produce as much as we can from resources that can be found on Mars (In situ resources). I think the way to do that is to make the systems in a Cell as simple as possible, so that they can be made on Mars. Even if many of those items cannot be made by the first Martian base, which has several Cells, we should be able to produce those items later. As the base expands, the capabilities of the Martian base will expand with it if we plan things right.

For example, in post#6 I introduced a gravity fed watering system, along with a dehumidifier that does not have any moving parts. In post#11 I showed how such a dehumidifier works and my suggestion is for the dehumidifier to be built on Mars. I showed pictures of a refrigerator at Pioneer Village that was made in 1925. An "absorption dehumidifier" could be made that works on the same principle. This implies that manufacturing capability on Mars would only have to be equal to that of 1925 in order to build such a dehumidifier.

Note that manufacturing capabilities on Mars do not need to be near as good as Earth in order to produce the things we need on Mars. On Mars, manufacturing capability will get better and better as a Martian base expands. Being able to build things on Mars, (In situ resources), reduces the amount of supplies that need to be sent to Mars.

Ideally, we want a resilient solution that can tolerate some failures.

Absolutely, that is a "must" that we always need to keep in mind. You have told me that you've done SQL programming, so you have probably often heard the term "fault tolerant." What we need is "fault tolerance" on Mars.

In Post#12 I explained the Air Pressure Control System, and I had mentioned that each Cell had its own separate Air Pressure Control System. I also described a scenario in which a Martian base had three Cells, each with their own separate Air Pressure Control System. At first glance this may seem to be a bad design.

Why have three separate Air Pressure Control Systems? Why not have one big Air Pressure Control System, rather than three smaller ones? Wouldn't it be cheaper because of "economy of scale"? Wouldn't one Air Pressure Control System be lighter than three, and therefore would be less mass to send to Mars?

The reason I have proposed three different Air Pressure Control Systems is because of redundancy. Having one large Air Pressure Control System, rather than several small ones, might seem like a better solution because of economy of scale, but the truth is we need this type of fault tolerant as you just described. I think we're going to run into this type of situation often.

Is this system something that can be maintained by someone with appropriate technical training?

What I'm attempting to do, is to bring to the table, a proposal of a Martian base that can be maintained by a minimal number of people. As I mentioned in post#2, I'm referring to a "base" of about 4 people, and at some point the base will grow to 10 people, and sometime in the future 20 people, and so on. We'll learn how to me more efficient as the base expands. If we do things right, we'll also have more resources as the base expands.

As far as picking the right people, I think that NASA, SpaceX, the European Space Agency, the Jet Propulsion Lab, and a whole lot of other space agencies have done an incredible job of picking the right person for the task at hand. I have nothing to offer or advice to give them in picking the right people. They are a lot better at that than I could ever be.

I think another way of looking at what you're asking, is that we ask ourselves if we have a base for 4 people, do 4 people provide enough labor to maintain the base? Or if we had a base of 10 people, is the labor of 10 people enough to maintain a base that is large enough to support 10 people? The more people we have, the more labor we have available. But the problem is that the more people that we have, the bigger the base needs to be, which requires more labor to maintain. So if the base is twice as big and it requires twice the labor to maintain it, then we are not gaining anything by making the base bigger. It's an interesting problem if you stop and think about it.

A lot of complex systems are maintained and repaired by people who may not have substantial general science education, but they do have a significant amount of tightly focused technical knowledge and training intended to make them specialists when it comes to the handful of systems they work on.

That is true, and you know that's exactly what Henry Ford did. Henry Ford did not hire the highest skilled and therefore highest priced worker. Henry Ford developed a system that was so simple and so robust (fault tolerant) that a lesser skilled person was capable of completing the task. Henry Ford always said that many people need structure, and he provided that structure in his system of building motorcars.

We would need operator / technician training courses intended to teach basic operation theory, all the equipment-specifics related to the types of equipment required, practical hands-on training, followed by a demonstration of skills in a mock operational environment.

Agreed. I think the best way to do this, is first have a plan on what exactly we are going to do once we set foot on Mars. Then we need to have, in extreme detail, what is the next step that we are going to do on Mars, and the third step, and many steps thereafter. If we have a plan like this all mapped out, then we can do exactly what you just said. We can set up simulations to do the "hands-on training" and the "mock operational environment" you mentioned.

The problem as I see it, and this is just my opinion, hopefully anyone reading this won't get too upset with me for saying this. But I haven't seen any detailed plan on what exactly we're going to do once we get to Mars, and how it will expand with a minimal amount of labor, and a minimal amount of supplies sent from Earth. Again, I cannot speak for Dr. Johnson, but if I interpret what he said and I quoted above in post#2, we need to establish a "base" or "outpost" and "try out the techniques and hardware (brought from home) that might possibly enable you to live off the land". If I'm understanding Dr. Johnson correctly, I believe he and I are thinking along the same lines.

I find this problem to be both depressing and exciting. The reason I say this is exciting, is because if no one has come up with a practical design for the first Martian base, then that is an opportunity for those of us on this forum to work together and come up with a list of ideas and try to put together something that will work. This requires that a lot of us come together with different backgrounds and different ideas, and that we all listen to each other, and not bully each other every time someone presents an idea that is different from our own, or get bent out of shape every time someone tells us something we don't want to hear. We can't afford to be so thin skinned. All of us will need a high level of emotional intelligence to take on such a task.

kbd512 · 2023-05-08 17:16:51

If you're looking for a detailed explanation of "what to do" after landing, that depends upon what your mission is. In broad general terms, in the military and for piloting aircraft, you execute checklists. Tasks to complete stem from those checklists.

Right after you land, there are three primary tasks:

1. Assess whether or not there are any immediate dangers to the lander, crew, or equipment.
2. Ensure your people are physically and psychologically fit for the arduous tasks ahead.
3. Ensure your equipment is physically sound (not damaged during transit or malfunctioning) and completely inventoried.

If you've done all that and no serious deficiencies are noted, then you're off to a good start. If not, then damage control begins. We will do our utmost to assure completion of mission regardless of personnel or system casualties. I don't think it's practical to expect 4 people to function as their own miniature society for 2 or more years. A few people can operate that way, but most cannot, regardless of education and training. 12 people is a realistic minimum. Humans banded together into tribes for a reason. There is capability in numbers. A task that might be very taxing or unrealistic for 4 people to perform might only be a routine work day for 12 people. The ability to work in shifts needs to be considered. Mere survival is a 24/7/365 task. You need at least a pair of crew members available at all times. I've worked plenty of 12 hour to 16 hour days in the military, so I can tell you that most motivated people can do that for awhile, but asking them to do it for years at a time is demanding more than most people can tolerate, long-term.

Steve Stewart · 2023-05-12 20:39:40

SpaceNut,
Woah! Stop! Hold your horses partner! What you are posting has nothing to do with my proposal. What I am proposing is being completely misunderstood. What I am proposing is completely different than anything you have ever seen. This is a totally new, completely different, "think outside the box", type of proposal.

SpaceNut wrote:
Reminder 4 cargo starships, 2 cycles before a crew can be able to return home is only starting place of 500 tons.

No, not 4 cargo starships, not 2 cycles, not 500 tons required as a "starting place". None of that is in my proposal. You're referring to a different proposal. None of that is any part of this proposal. To repeat, this is a completely new, totally different, far outside the box thinking of anything you have seen. What I am showing is a "Martian Base" located on Mars. It is designed to become self-sustaining base much sooner, and with far less payload, than other proposals. Let me repeat what I said, and what Dr. Johnson said, in post#2.

Dr Johnson wrote:
I think this discussion suffers from relatively-undefined terms, as well as an unclear overall goal.

Dr Johnson is correct. Whenever we're talking about a proposal, we need to define the terms and scope of what we are proposing. What I'm proposing is completely different than anything you've seen. I did define the terms and scope of this proposal. Let me repeat what I said in post#2:

Steve Stewart wrote:
I view the first Martian base as having a minimal crew of less than 10 people.
...
In this proposal I am referring to a small base whose objective is to grow. I am not proposing a settlement with a large population of the general public.
...
Everything I'm about to describe I have designed it to be as simple as possible. The idea is for much of this to be built on Mars, or at the very least replacement parts can be built on Mars.

The stuff you have posted refers to a "settlement", not a "Martian Base", which is what I am proposing, and is the purpose of this thread.

Dr Johnson wrote:
Using those definitions, "settlement" is NOT what you do in the initial landing or landings on Mars (or the moon, or anywhere else). WRONG GOAL!!! You are very far from being ready to do that! You do NOT yet really know "for sure" how to "live off the land". That appropriate-goal lesson is centuries old, even here on Earth. Read your history.

Lets talk about energy, and why storing energy is important (Title of post#2). I gave a couple of examples of sources of energy in post#2.

Steve Stewart wrote:
I'm making the argument that any time a source of electricity, whether it be from solar, nuclear (such as Kilopower), or any other type, all sources of electricity can benefit from a method of storing energy, because storing and retrieving energy reduces waste.

I went on to explain that ANY type of energy source that is producing 30kW (as an example) and it has a 20kW load, 10kW is being wasted.
Let me say that a different way:

ANY source of electricity, that is not running at full power, is wasting electricity.
If ANY source of electricity has a load that is 90% of it's output, then 10% is being wasted.
If ANY source of electricity has a load that is 80% of it's output, then 20% is being wasted.

The type of source of energy, and its total rated load capacity, are irrelevant for what I'm saying. Listing different energy sources and their power output isn't relevant to what I am proposing, they factor out of the equation. What I am doing is showing ways of reducing waste.
Let's talk about waste:

Forms of waste

I'm a degreed engineer with a few decades of experience. I've spent part of my career working in manufacturing. In the World of manufacturing, it's important to identify, and then remove forms of waste. Many experts have said that one of the reasons of Henry Ford's success was his keen ability to find and eliminate waste. Henry Ford's 1926 book "Today and Tomorrow" lists several forms of waste. Chapter 8 of that book is titled "Learning from waste". In the 1980's, author Jeffrey Liker wrote a book called "The Toyota Way". To this day, the book "The Toyota Way" is studied by many manufacturing companies, to find ways of improving manufacturing. Chapter 2 of the book "The Toyota Way" states:

The Toyota Way
By Jeffrey Liker
Chapter 2
Toyota Motor Corporation struggled through the 1930s, primary making simple trucks. In the early years, the company produced poor quality vehicles with primitive technology (e.g., hammering body panels over logs) and had little success. In the 1930s, Toyota's leaders visited Ford and GM to study their assembly lines and carefully read Henry Ford's book Today and Tomorrow (1926).

Toyota came up with the catch-phrase DOTWIMP (pronounced dot-wimp) to identify their "7 forms of waste". Each of the letters in DOTWIMP represent a form of waste as shown in the image below. D - is for Defects, O - is for overproduction, T- is for transportation, W - is for waiting, I - is for (excess) inventory, M - is for (excess) motion, P - is for over processing. Together they spell "DOT-WIMP".

If we are going to build a Martian Base, we must work out the tiny details. Then study those details and look for forms of waste. It's how things are done, and that's what I am doing in talking about energy, and energy storage. What I am proposing is a way of removing one form of waste, when referring to energy storage. On Mars, there will be many forms of waste.

Let me again quote what Dr. Johnson said:

Dr Johnson wrote:
Using those definitions, "settlement" is NOT what you do in the initial landing or landings on Mars (or the moon, or anywhere else). WRONG GOAL!!! You are very far from being ready to do that! You do NOT yet really know "for sure" how to "live off the land". That appropriate-goal lesson is centuries old, even here on Earth. Read your history.

Steve Stewart · 2023-05-12 20:41:55

Lets take a look at the image that was posted in post#24. Below is a copy of the bottom right of that image. On the far right are two boxes colored green. One says "Biomass Production System (BPS)" and the other says "Growth Lighting System (GLS)".

I assume the "Growth Lighting System (GLS)" is a fancy name for LEDs used to grow plants, or for Martian sunlight, or some combination of the two. I assume the "Biomass Production System (BPS)" is a fancy name for plants. The "Biomass Production System (BPS)" points to the oval labeled "Biomass", which points to the box labeled "Food Processor".

The "Cell" that I introduced in post#6 contains all of these functions. Plants are grown in a Cell, which has the "Growth Lighting System (GLS)", and the "Biomass Production System (BPS)", and the "Biomass" all in one.

I assume the "Food Processor" is the processing of food, I assume that's the equivalent of peeling a potato, and the potato peelings are part of the "dry waste". I assume "Biomass Production System (BPS)" and "Biomass" shown must only be growing plants for food. The 4F's, which I mentioned in post#16 are not shown anywhere in this diagram.

In my proposal, someone processing food, such as peeling a potato, is the "Food Processor" in the diagram above. Any organic matter, left over from "Food Processing" is put into the compost bin, as I showed in post#6 and mentioned again in post#16. As I mentioned, composting can produce methane and hydrogen sulfide. This only occurs if part of the compost becomes anaerobe, as I explained in post#16 under the title "Composting on Mars".

In the diagram posted in post#24, I don't see anywhere that food waste is being recycled. If it is recycled, I don't see anyway of dealing with methane and hydrogen sulfide. If food waste isn't recycled, but is just thrown away, this is a major form a waste. I also don't see where human waste is being recycled, this is another major form a waste. This lack of detail, and not dealing with this type of major waste, is why a "500 tons is required as a starting place".

In my proposal (post#16) I show the recycling of both food waste and human waste. I also explained how vented gases from composting are processed (such as methane and hydrogen sulfide).

I suggest going back over and reading all of my proposal with a clear mind, one sentence at a time. Do not think of this as being something you have seen before, it isn't. Think about every sentence, and how the science works for everything I'm proposing. By no means are you required to do that SpaceNut. I do appreciate the effort. I just threw this proposal out there for anyone who would like to read through it and see a different way of thinking. Thanks to anyone who is willing to take the time to do that.

Last edited by Steve Stewart (2024-09-04 00:16:36)

tahanson43206 · 2023-05-13 08:30:34

For SpaceNut ... This is Steve's topic.

You are Senior Administrator.

You have the power to move your posts to another topic where they would be a better fit.

Steve may have a vision for how he want's his topic to develop.

You could ask him if that is the case.

I am hoping that more topics in this forum will flow in such a way that a reader would benefit by following the progression from the top.

In the past, (and especially in the archive) I can see a lot of ego related shoving and elbowing going on. We don't need that in the present forum.

We have only a few active members, and there should be little uncertainly about the views each member holds.

Please consider moving your posts and then interacting with Steve to see how he would like to see the topic develop.

(th)

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