Manufacture of Propellant at Locations away from Earth

tahanson43206 · 2023-11-09 10:20:35

This topic is offered as a vehicle for members to collect information and links on manufacture of Propellant away from Earth.

A number of fact filled posts already exist in the forum Archive. so this topic would be a good place for copies of those posts if a member has the time to look for them.

The most recent I can think of is one by kbd512, in which he described a way to use ordinary table salt to perform chemical operations on feedstock to make intermediate chemicals that will ultimately yield methane and oxygen.

This topic is NOT limited to any particular source of inputs to the manufacturing process. Competing entities are going to attempt to produce the needed propellant at a price just under the going rate, while achieving an acceptable profit for share holders.

(th)

tahanson43206 · 2023-11-09 10:21:23

kbd512 wrote:

Here is the electro-chemical process for making Sodium Chlorate (NaClO3), using salt (NaCl) and water (H2O) as feedstock:
https://www.chemengonline.com/wp-conten … um-21b.jpg
If you can obtain CO2 and H2O from Mars, then Sodium Chlorate is a storable solid white crystalline compound (much like NaCl), requiring no pressurization or temperature control. This infinitely reusable chemical will split H2 from H2O. Further heating the Sodium Chlorate (NaClO3) to 300C, after the water splitting, will then release the Oxygen.
Sodium Chlorate is used for everything from paper bleaching to cosmetics to pesticides, but the paper bleaching industry is a major user of this industrial chemical product.
That said, Hysata makes a 95%+ efficient reverse fuel cell that splits H2O. This is almost certainly the way to go. H2 from the reverse PEM fuel cell is fed into the Sabatier reactor. The Sabatier reactor combines CO2 and H2 gas into 1CH4 and 2H2O. Alternatively, CO and H2O combine into 1CH4 and 1H2O. Both types of electro-chemical reactions feed into the Sabatier process.
The primary advantage of Glucose is storability. Both Sodium Chlorate and Glucose will store indefinitely with zero pressure, irrespective of temperature (within the limits of Mars surface conditions), because they are solids.

tahanson43206 · 2023-11-09 10:26:07

SpaceNut has given 1200 as the number of tons of propellant to top off a Starship (as of late in 2023).

A manufacturing facility at a location away from Earth needs to produce propellant at a rate that matches the travel time of the customer vessel. If we assume 8 months as the time required to convert raw feedstock into 1200 tons of propellant, then the manufacturing facility needs to be sized accordingly. The facility needs storage containers for the methane and oxygen to be produced, as well as machinery to compress and cool both materials into a liquid state for loading into an arriving Starship.

Update: If we assume 30 days per month for 8 months, then we have 240 days to manufacture 1200 tons of propellant, or 5 tons per day.

That would be 5 tons per day delivered to the storage tanks. Compression and cooling can be done in a separate process, but it too should be able to handle 5 tons per day.

Because there are inefficiencies at every stage of the process (or so I am told) the manufacturing facility needs to be able to hand much more than 5 tons of reactants to produce the required output.

As a ballpark opening guess, I'll offer the capacity of 10 tons per day to account for inefficiency. No atoms are lost during the process, but the the ones that do not complete the chemical process at a given point must be collected and fed back through until they do complete.

(th)

SpaceNut · 2023-11-09 20:53:18

The fuel is a tradeoff of launch mass and payload that will be returning to earth with 1200 mT being the maximum that the starship can hold. It is also where we pick the return path distance as that requires one to know how long they wish to transit with the payload they are choosing to return with. The tall order is the initial landing which a starship has never done on Mars let alone with max cargo and how many with in a close proximity to each other without causing damage to the others as they land and still get them to do what we want as there is no means to move the stuff to make the system function.

https://space.stackexchange.com/questio … -frequency
mars trip would last around 2.5 years in total with 0.7 years transfer both ways and a little over a year on the surface.

So, if you have the equipment on the ground preload and running the first yr 2025 with some wanting the total to be ready before the next launch wind which is 2027. Of course, if you have 7 more months to go and that is all which is not done, I would if given the choice to give the mission a go as you already have most of the fuel required and plenty of extra time to produce all of what is needed for the return first trip.

tahanson43206 · 2023-11-09 21:22:33

For SpaceNut re #4

Thank you for the chart showing Hohmann Transfer opportunity dates for Mars!

SearchTerm:Hohmann transfer opportunity chart

If the Filling Station has 1200 tons of propellant on hand, and the Starship does not need it all, so much the better. There will be other customers without a doubt.

(th)

RobertDyck · 2023-11-10 07:41:31

One reason for this thread is a recent discussion of the most practical propellant for return to Earth from Mars. Assumption was carrying return propellant all the way from Earth. I was disappointed, I thought we were past that. Some people in NASA are still ignorant, and that's saying a lot. The Mars Direct plan would produce return propellant on Mars, from stuff found on Mars. This DRAMATICALLY reduces launch mass.

A plan by Boeing in 1968 would require 6 launches of a Saturn V, and all modified. It would use 3 nuclear rocket stages strapped side-by-side for Earth departure, another for Mars orbit insertion, and another for Mars departure. That's 5 propulsion stages, each of which is launched separately. A 6th launch of a Saturn V would deliver the spacecraft, with Earth return capsule, a module for living space, and a Mars lander. Propulsion stages would be the 3rd stage of a Saturn V, delivered to Low Earth Orbit for assembly with all propellant intact. Just as Skylab was launched into LEO with a Saturn V using just the first 2 stages, the 3rd was Skylab, in this case the 3rd stage is a fully fuelled propulsion stage. And it wouldn't be a normal 3rd stage, it would have the same diameter as the 1st and 2nd stages, and as long as the 1st stage. Saturn V used RP1/LOX for the first stage, LH2/LOX for 2nd and 3rd stages, but the Mars propulsion stages would use a NERVA engine so propellant would be all LH2. To be fair, total length/height including engine would be the same as S-1C stage, but NERVA is a tall engine to accomodate the reactor; tank for the new stage would be slightly shorter than the total of RP1 and LOX tanks for S-1C. To be able to launch a stage this heavy, the Saturn V would also have 4 Solid Rocket Boosters. Each SRB would have 4 segments, same diameter as SRBs for Shuttle, but slightly shorter.

Robert Zubrin and his partner David Baker gave their first presentation of Mars Direct to NASA in June 1990. Old guys in NASA who worked on Apollo got excited. This required just 2 launches of a rocket the same size as a Saturn V, and that's an unmodified Saturn V. No nuclear rocket required. The Area rocket would be based on Shuttle with a core stage based on the ET with same diameter as ET. The new rocket would include a pair of SRBs, just like Shuttle. Apollo guys launched several missions to the Moon with a rocket this size. Ares would launch from the same pad as Shuttle, using the same Mobile Launch Platform as Shuttle and same crawler. The launch pad is the same one that launched Apollo 11 to the Moon, so using that same pad again for a human mission to Mars would definitely work!

The problem is when mission planners insist on bringing return propellant from Earth. Mars Direct includes several innovations, the key enabling one is In-Situ Propellant Production. Without it you get something as big as the IMIS mission plan from Boeing in 1968.

RobertDyck · 2023-11-10 07:54:07

I would like to mention work done in the 1980s by John Wickman, called Lunar Soil Propellant. This is a way of producing In-Situ Propellant on the Moon. It requires harvesting Moon dust/soil/dirt/regolith (whatever name you want to use) and smelting to produce aluminum. He came up with a couple options. One was powder aluminum mixed with Liquid Oxygen as a mono-propellant. He built a small brass-board demonstrator under a contract from NASA. It worked and flame did not back-up into the tank causing the tank to explode. This was a concern. His second opinion was bi-propellant. Nitrogen gas would blow powder aluminum out of the tank into the rocket engine, and a second tank would hold LOX. The issue is nitrogen gas. Aluminum ore is an oxide, so smelting aluminum metal produces oxygen as a byproduct. However, the Moon doesn't have nitrogen. There's a tiny bit at the bottom of craters at the poles, where sunlight never touches it, but that's even more rare than lunar ice. So basically using this bi-propellant requires shipping nitrogen from Earth.

Lunar Soil Propellant - Wickman Spacecraft & Propulsion Company

tahanson43206 · 2023-11-10 08:43:19

For RobertDyck re Posts 6 and 7 ..... Thank you for these additions to the topic, with historical references and inSitu opportunties described.

This topic is intended (insofar as possible) to become a repository for information useful to an entrepreneur thinking about providing propellant supply at locations away from Earth. This topic is not about government research projects, important as those are.

kbd512 has contributed a post about use of ordinary table salt to manufacture methane and oxygen. (see Post #2 of this topic).

I'm hoping that our members will collect everything that an entrepreneur needs to know to secure funding for a propellant supply service. The argument over whether inSitu manufacture is superior to Earth supply will solve itself. If no one is able to manufacture propellant on Mars, then the suggestion while interesting,. is essentially worthless.

This topic is set up to consider destinations other than Mars. Wherever humans venture in the Solar System, they are going to need support infrastructure. The first expeditions will have to bring everything with them, but as traffic increases there will be sufficient income opportunity to justify permanent support services.

(th)

Calliban · 2023-11-10 10:20:48

tahanson43206 wrote:

kbd512 wrote:
Here is the electro-chemical process for making Sodium Chlorate (NaClO3), using salt (NaCl) and water (H2O) as feedstock:
https://www.chemengonline.com/wp-conten … um-21b.jpg
If you can obtain CO2 and H2O from Mars, then Sodium Chlorate is a storable solid white crystalline compound (much like NaCl), requiring no pressurization or temperature control. This infinitely reusable chemical will split H2 from H2O. Further heating the Sodium Chlorate (NaClO3) to 300C, after the water splitting, will then release the Oxygen.
Sodium Chlorate is used for everything from paper bleaching to cosmetics to pesticides, but the paper bleaching industry is a major user of this industrial chemical product.
That said, Hysata makes a 95%+ efficient reverse fuel cell that splits H2O. This is almost certainly the way to go. H2 from the reverse PEM fuel cell is fed into the Sabatier reactor. The Sabatier reactor combines CO2 and H2 gas into 1CH4 and 2H2O. Alternatively, CO and H2O combine into 1CH4 and 1H2O. Both types of electro-chemical reactions feed into the Sabatier process.
The primary advantage of Glucose is storability. Both Sodium Chlorate and Glucose will store indefinitely with zero pressure, irrespective of temperature (within the limits of Mars surface conditions), because they are solids.

I missed this before. Assuming I have understood correctly: the reaction between sodium perchlorate and water, removes the oxygen atom from the water liberating hydrogen. The perchlorate can then be regenerated by heating to 300°C. The net reaction:

2H2O + heat @300°C = 2H2 + O2

The really interesting thing about this reaction is that heat at this temperature range is produced in abundance by light water reactors.

There is no advantage whatever to using glucose as a propellant if we are starting with CO2 and H2 as syngas. Methanol has higher energy density, is a room temperature liquid and is easier to synthesise.

CO2 + 2H2 = CH3OH. I cannot remember which catalyst is needed. But once you have methanol, reactions over a zeolite catalyst can build up longer chain hydrocarbons. If we can synthesise methanol we have the feedstock for plastics industry. And of course there is dimethyl-ether:

2CH3OH = CH3-O-CH3 + H20

This fuel has a boiling point of -24°C and has 80% of the volumetric energy density of diesel. As the fuel is already partially oxidated, the energy density of DME/O2 bipropellant is comparable to LOX/RP1.

Methanol doesn't freeze until -97°C. It is also non-corrosive to steel. So you can store this on Mars as a liquid in lightly pressurised (<1 bar) steel tanks on the surface. It may be the propellant of choice for long-range surface vehicles. Methanol thermophysical properties:
https://www.engineeringtoolbox.com/meth … _1209.html

At -50°C, methanol remains liquid and vapour pressure is 10mbar. So this fuel is storable at ambient pressure on Mars. It can be stored in thin walled steel tanks. The vehicle fuel tank will not need pressurisation either and can work much the same as an Earth gasoline tank. Martian atmospheric pressure is close to triple point for LOX. But it could be stored as an ambient pressure liquid if temperature is controlled within a narrow range. So we can refill vehicles with LOX/methanol on Mars using simple gravity flow by opening a valve. This allows refuelling in much the same way as you would do it at a gas station on Earth.
https://www.wolframalpha.com/input/?i=o … se+diagram

Last edited by Calliban (2023-11-10 11:11:56)

tahanson43206 · 2023-11-10 15:04:50

For Calliban re #9

Can you size this reactor to fit in a single Starship?

The really interesting thing about this reaction is that heat at this temperature range is produced in abundance by light water reactors.

The desired output is 5 tons of Methane and Oxygen per day, but the plant needs to be sized well above that level due to losses that (I understand) occur at every stage of the process.

(th)

Calliban · 2023-11-10 15:57:00

My previous assumption was incorrect. Sodium chlorate is produced by electrolysis of a sodium chloride water solution.
https://link.springer.com/article/10.10 … 017-1100-3

NaCl +3H2O = NaClO3 + 1.5H2.

The process requires some 5000kWh of electric energy per tonne of perchlorate. Some 60kg of associated hydrogen are produced, which equates to 300MJ/kg of H2. So the perchlorate process would be less efficient than ordinary water electrolysis.
*******************

Additional (1): The copper-chloride process would appear to be the most promissing thermochemical process.
https://en.m.wikipedia.org/wiki/Copper% … rine_cycle

The highest reaction temperature needed is 530°C. This makes the process compatible with a number of Gen IV concepts. Perhaps most promissing is the sodium cooled fast reactor, which operates at temperatures of 550°C. A 530°C operating temperature allows for some thermal gradient across heat exchangers.

Additional (2): Direct thermolysis of water is potentially interesting. Go to slide 15 in the presentation below.
https://www.slideserve.com/jontae/lectu … production

At 1730°C, some 0.69% of water molecules dissociate into hydrogen. I find myself wondering if it is possible to build a high temperature nuclear reactor that directly dissociates water into H2 and O2 within the core itself. The fuel would be uranium oxide, clad in tungsten, with a solid metal oxide sleeve to protect the clad from oxidation. Hydrogen would be extracted by passing the superheated steam across metal oxide tubes. A pressure gradient between the outside and inside of the tubes would allow hydrogen to diffuse through the grain boundaries into the interior of the tube, whilst the O2 and H2O molecules are too large to diffuse in this way. The remaining mixture of steam and O2 would exit the reactor through a counterflow heat exchanger, through which additional steam is added to the reactor.

In this way, nuclear heat can be converted directly into H2 and O2 within the reactor. This is probably something we could build on Mars, away from the stifling control of organisations like the NRC and ONR.

Last edited by Calliban (2023-11-10 17:13:01)

tahanson43206 · 2023-11-10 18:28:03

For Calliban and kbd512 re electrolysis ....

Are there possible advantages to the non-traditional water electrolysis process? Calliban seems to be showing that alternatives to ordinary water electrolysis are less efficient? Perhaps there are system advantages? Electrodes are at risk in any electrolysis system. (that seems like a reasonably safe assertion).

Perhaps the sodium chlorate system allows electrodes to last longer. A system on Mars is going to have to be designed like a Maytag Washer.

Here is the abstract from the link provided by Calliban in post 11 above.

Abstract
Current efficiency in the sodium chlorate process is a key issue in the evaluation of the power consumption. A pilot cell unit for executing the sodium chlorate process was constructed to study the current efficiency of the anode and cathode separately. The effects of sodium dichromate and sodium sulphate concentrations and the electrolyte temperature on the anode and cathode current efficiencies were studied. Corrosion products formed on the mild steel cathodes after their removal from the cell were characterised using X-ray diffraction and infrared spectroscopy. The results show that the cathodic current efficiency increases with increasing dichromate concentrations in the electrolyte until approximately 5 g dm−3 is reached. At this optimum concentration of dichromate, the presence of sulphate ions decreases the cathodic current efficiency. For moderate increases in temperature, the cathodic current efficiency increases, but oxygen evolution is promoted, and the power consumption also increases. Surface characterisation of the electrodes after their exposure to air shows two primary types of behaviour, depending on the process parameters. At low dichromate concentrations, amorphous corrosion layers are formed, while at higher concentrations, reduced forms of iron hydroxides, i.e., “green rust”, are identified. Although the electrodes were positioned at the open circuit potential for 40 min before their removal from the cell, chromium remains on the cathode surface. This result might explain the corrosion-inhibiting effect of the addition of chromate to the electrolyte. The results from this study can be used to optimise operating procedures in real plants, decrease the energy consumption and minimise the environmental impact of these processes.

(th)

Calliban · 2023-11-10 18:45:58

Producing hydrogen through sodium perchlorate production does not appear to be energetically favourable. Unless you are producing the perchloride anyway and hydrogen is a byproduct. High temperature electrolysis is promissing, as are some of the thermochemical processes. Direct thermolysis requires very high temperatures. But HTE has already demonstrated a roughly 2-fold reduction in the electricity needed to produce each kg of H2. This is progress, because heat is far cheaper than electricity.

tahanson43206 · 2023-11-11 07:20:16

For Calliban re making methane from carbon and hydrogen....

If a free carbon atom is placed in a chamber with four hydrogen atoms, and STP, nothing will happen (I am told).

However, it appears that methane has been produced naturally over millions of years on Earth, under appropriate conditions of temperature and pressure.

I am wondering if simple compression and heating can provide the conditions to make methane, given a supply of free carbon and hydrogen?

This would be a problem for a mechanical engineer, I would think.

(th)

SpaceNut · 2023-11-11 09:46:09

The mars soil contains both water and perchlorate with in it so when the soils is baked, we can capture both of these while returning the heated soil back to the surface.
What I cannot do is estimate the percentage of the solution which will be obtained by the process.
An electrolyte is required to lower the water electrolysis energy required to break the water into elements for use in the reactor.
In the other topic steam is the common earth water source to be put into the reaction so is that less energy intensive or is it more than breaking the bond.
So, what is the steam energy requirement?

tahanson43206 · 2023-11-12 13:36:54

tahanson43206 wrote:

In the session at the link below, ChatGPT(4) and I opened what I hope will become a series of interactions that will lead to understanding of a possible process for making methane and directly from carbon and hydrogen, without wasteful intermediate processes. This opening session sets the stage for a deeper dive into the chemistry and physics involved.
https://docs.google.com/document/d/1tU4 … sp=sharing
The discussion should be accessible to the average person, and certainly to the folks who are members of this forum.
Update several hours later .... It appears that persistence and ChatGPT's talents have allowed us to reach the goal I'd hoped might be achievable.
The transcript at the link below includes the one above, but it includes a set of data points that anyone can feed into a modern calculator or into a spreadsheet program to find the "Magic" numbers needed to make methane from simple carbon and hydrogen atoms.
https://www.dropbox.com/scl/fi/tfifi1pz … ckgwn&dl=0
There is plenty of work ahead... To design a practical machine to utilize this method will require the talents, knowledge and experience of professional level mechanical engineers, but there appear to be no roadblocks standing in the way. As nearly as I can tell, everything needed has been done before on Earth, to the point that most of it is routine.

(th)

SpaceNut · 2023-11-12 15:36:55

If you are using a gaseous co2 & H2 then its a sabatier reactor
https://tfaws.nasa.gov/wp-content/uploa … S-2018.pdf
You need the triple point pressure for both to field the reactor.

using plain C or steam makes it just a reaction chanmber.

tahanson43206 · 2024-02-22 11:51:38

This post is reserved for a copy of a post from Calliban, entered into a topic about landing on Mars.

Calliban wrote:

Some potential long-term storable liquid propellants that we can talk about making on Mars.
Fuels: Propane, Butane, methanol, dimethyl ether. Methanol can be synthesised using using the same chemical reactor technology used to make methane. The catalysts are different and the CO and H2 are fed into the reactor in different proportions. Dimethyl ether has a vapour pressure similar to propane at room temperature. It is made from a condensation reaction between two methanol molecules over a catalyst. Any methanol producing sabateur reaction will also produce DME. But higher DME selectivity can be designed for.
Oxidants: LoX, HNO3, N2O, NO2, H2O2, F2. LOX and F2 give the highest exhaust velocity. F2 is so toxic that it just isn't a serious contender. Concentrated nitric acid is a metastable liquid and is 40% denser than water. But is very corrosive. Even 316SS has a limited life exposed to it. Under standard conditions, it will evolve NO2, which will form a gas over its surface. H2O2 has stability issues that can be reduced via chilling. I have heard of N2O (laughing gas) used as oxidiser. Energy density is reduced and from memory, there were problems with ignitability. But it is storable as a saturated liquid at room temperature and this is its selling point. I don't know much about NO2, aside from its toxicity.

(th)

GW Johnson · 2024-02-22 16:12:58

I've often seen "perchlorates" mentioned as being in Martian soil, but which ones? They are by no means all the same sort of thing. Ammonium perchlorate is a good solid rocket oxidizer. The rest are no better than the black powder oxidizers Na- and K- nitrate, and most are worthless for that rocket oxidizer purpose in any way, shape, or form.

Here on Earth, ammonium perchlorate is an evaporite salt in the desert southwest, but not a very common one. There used to be two AP producers in Utah, but one blew up decades ago. AP is sensitive and mass-detonable. Class 1.1 by itself, but you can make non-mass-detonable class 1.3 solid propellants with it. To the best of my knowledge, there is only one remaining AP producer in the US.

GW

SpaceNut · 2024-02-23 19:59:58

Here is the Marco polo topic first link for fuel manufacturing lander for mars.

https://kiss.caltech.edu/workshops/isru … anders.pdf

New Mars Forums

Announcement

#1 2023-11-09 10:20:35

Manufacture of Propellant at Locations away from Earth

#2 2023-11-09 10:21:23

Re: Manufacture of Propellant at Locations away from Earth

#3 2023-11-09 10:26:07

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#4 2023-11-09 20:53:18

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#5 2023-11-09 21:22:33

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#6 2023-11-10 07:41:31

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#7 2023-11-10 07:54:07

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#8 2023-11-10 08:43:19

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#9 2023-11-10 10:20:48

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#10 2023-11-10 15:04:50

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#11 2023-11-10 15:57:00

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#12 2023-11-10 18:28:03

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#13 2023-11-10 18:45:58

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#14 2023-11-11 07:20:16

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#15 2023-11-11 09:46:09

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#16 2023-11-12 13:36:54

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#17 2023-11-12 15:36:55

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#18 2024-02-22 11:51:38

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