DeGrasse Tyson's Mars challenge to Elon Musk

kbd512 · 2017-04-14 17:05:45

Dook wrote:

Sulfur is readily available on Mars? I'm sure it is, spread out and mixed with silicon and other elements. You want to drive around Mars, scoop regolith into a cart, pull it back to the base, separate the impurities somehow just to get minimal amounts of sulfur, go back and do it over and over again?

Yes, sulfur is readily available on the surface of Mars and yes, I would like to drive a robotic truck around and scoop up regolith to obtain both the aggregate and the sulfur at the same time.

A Novel Material for In Situ Construction on Mars: Experiments and Numerical Simulations

Dook wrote:

Mars temperatures don't affect the sulfacrete? Sulfur melts at 239 degrees F on the Earth. With Mars low atmospheric pressure, at what temperature will sulfur melt? If the melting temperature is too low, will the sulfacrete still harden on Mars?

Read the PDF I posted in the link above for sulfacrete manufacturing. 3D printers heat the material that goes through the print head. Molten Sulfur is mixed with a fine aggregate to produce sulfacrete. The mixture hardens in approximately one hour in Mars atmospheric conditions and Mars atmospheric conditions are sufficient to prevent Sulfur from going directly from solid to gas.

Dook wrote:

Why build a secondary structure and then heat, oxygenate, and provide electricity to two structures when you already have one that works? Why spend time to do that? Why use the rover for that? Why use rocket space for the sprayer and centrifuges when the tuna can provides habitat?

The habitat modules that we can affordably send to Mars are rather delicate compared to a surface structure made from a meter of sulfacrete, are rather small compared to the average house, and provide insufficient radiation protection for extended duration habitation. If we have to send absolutely everything from Earth, then there is no affordable way to colonize Mars. Actual materials scientists have done actual experimentation using the kinds of actual materials that our rovers have actually identified on the surface of Mars.

Dook wrote:

In 500 years, when settlers on Mars start having babies, we'll need home building equipment on Mars.

The industrial revolution didn't take 500 years. Going from computers that were the size of buildings to things we could implant in someone's brain to help blind people see again took less than 50 years. The pace of technological innovation is accelerating. 3D printers are a good example of how manufacturing processes that previously took days / weeks / months to complete can now be completed in a matter of minutes or hours.

louis · 2017-04-14 17:18:44

Last time, maybe a few years ago, I looked at SAFE-100 it hadn't been built - it was just a design. Is there actually one in existence now?
I presume you will take two for the first mission - is that right? My mission proposal would be fail-safe as you would have PV panels operating years before humans land - charging pre-landed batteries and making methane. Within a few years the young Mars colony will be producing its own PV panels with 3D printer technology. Would they be able to produce nuclear reactors? I doubt it.

Oldfart1939 wrote:

Louis- The SAFE-100 is simply a turn-key operation, once all the electrical system is in place and the reactor in it's sheltered location. Chance of malfunction? Very, very low. But--that's why we bring along at least 5 of them over time. Four of them running, but only one at maximum electrical output. One as a reserve spare.

Dook · 2017-04-14 18:47:21

kbd512 wrote:

Dook wrote:
Sulfur is readily available on Mars? I'm sure it is, spread out and mixed with silicon and other elements. You want to drive around Mars, scoop regolith into a cart, pull it back to the base, separate the impurities somehow just to get minimal amounts of sulfur, go back and do it over and over again?
Yes, sulfur is readily available on the surface of Mars and yes, I would like to drive a robotic truck around and scoop up regolith to obtain both the aggregate and the sulfur at the same time.
A Novel Material for In Situ Construction on Mars: Experiments and Numerical Simulations
Dook wrote:
Mars temperatures don't affect the sulfacrete? Sulfur melts at 239 degrees F on the Earth. With Mars low atmospheric pressure, at what temperature will sulfur melt? If the melting temperature is too low, will the sulfacrete still harden on Mars?
Read the PDF I posted in the link above for sulfacrete manufacturing. 3D printers heat the material that goes through the print head. Molten Sulfur is mixed with a fine aggregate to produce sulfacrete. The mixture hardens in approximately one hour in Mars atmospheric conditions and Mars atmospheric conditions are sufficient to prevent Sulfur from going directly from solid to gas.
Dook wrote:
Why build a secondary structure and then heat, oxygenate, and provide electricity to two structures when you already have one that works? Why spend time to do that? Why use the rover for that? Why use rocket space for the sprayer and centrifuges when the tuna can provides habitat?
The habitat modules that we can affordably send to Mars are rather delicate compared to a surface structure made from a meter of sulfacrete, are rather small compared to the average house, and provide insufficient radiation protection for extended duration habitation. If we have to send absolutely everything from Earth, then there is no affordable way to colonize Mars. Actual materials scientists have done actual experimentation using the kinds of actual materials that our rovers have actually identified on the surface of Mars.
Dook wrote:
In 500 years, when settlers on Mars start having babies, we'll need home building equipment on Mars.
The industrial revolution didn't take 500 years. Going from computers that were the size of buildings to things we could implant in someone's brain to help blind people see again took less than 50 years. The pace of technological innovation is accelerating. 3D printers are a good example of how manufacturing processes that previously took days / weeks / months to complete can now be completed in a matter of minutes or hours.

Sulfur is readily available on Mars? In what percentages? Minimal amounts? If it's there in small amounts that means you have to move an incredible amount of material to get enough for one home.

I will read the PDF.

The habitat modules we send to Mars are delicate? They're going to withstand launch, aerocapture, parachute deployment, rocket firing and abrupt landing.

If we have to send everything then there is no affordable way to colonize Mars? I agree but everything you want to send has to be more important than food. Also, every shipment of people to Mars will be in a tuna can, so, they will always land in a habitat. So, having more habitats is not a need while having more greenhouses is a need. Having more electricity is a need, to a point. Having more water, extra food, and spare parts is important.

The 3D printer needs months of work to obtain enough sulfur so it can make a home. And your rover can't work in dust storms because it uses solar power and even when it is sunny your rover can operate for only one hour before it has to be recharged. And you need a centrifuge. And another building to do all this in since you can't do it in the tuna can habitat or greenhouse.

You guys think everything is going to work perfectly from the start. Everything is not going to work, things are going to be trial and error.

The first landings are going to be all over the place. Getting things together might take months, maybe a year, if you have to cross rock fields because you will have to clear a road for the rover and the towed Moxie/Nuclear Reactor/Greenhouse container.

The rover is going to get stuck towing things back to base, bet on it, maybe over and over and over again. And if the rover breaks or gets stuck permanently, they're dead.

The first greenhouse is either going to get too hot or too cold and plants are going to constantly go dormant or die.

The Moxie is going to shut itself off because of an incorrect fault and have to be opened up and a new sensor installed.

The oxygen storage tank in your habitat is going to have a slow leak that you can't fix because that would release all the oxygen.

The 100% water recycling system is going to operate at 90% for some reason. The habitat will have a slow pressure leak. The habitat door seal will come off and get slammed in the doorway, cutting it.

One of the settlers will steal extra food and water.

One of the settlers will become lazy and depressed because things aren't going as well as they thought they would.

The greenhouse will have many leaks and it will take a week to reseal all the panels but they won't be able to do it because they will run out of sealant.

Someone will twist their ankle and not be able to work for 3 days.

A dust storm will hit and last for 4 months causing the greenhouse temperature to drop and all your fruit trees will drop their leaves and fruit and go dormant.

You guys have never fixed complicated machines so you think it's all going to go fine. It's not going to go fine but at least they will have a 3D printer instead of some extra food and water.

The industrial revolution didn't take 500 year? But weren't there already a lot of plants growing by then? And fresh water rivers and lakes? And oxygen all over the place?

3D printers reduce manufacturing time? They do. They are great for some things. You want luxury as soon as possible on Mars. I want extra food, extra water, full oxygen tanks, and extra critical parts.

If I was on Mars you could send me a fourth and fifth Moxie before you send me the first 3D printer. The printer I don't need to survive, the Moxie is life and death.

kbd512 · 2017-04-14 23:28:27

Sulfur is thought to make up as much as 17% of Mars by total mass. Sulfur compounds are present in nearly every sample taken from Mars. The concentration is higher in some places compared to others, but the point is that Sulfur is virtually everywhere on the surface of Mars in the same way that Iron oxides are virtually everywhere on the surface of Mars.

My comment about space habitation modules being delicate is applicable to pressurized aluminum and composite cans that are thinner than a scaled up soda can. A meter of concrete is not delicate, by way of comparison. More importantly, a meter of concrete will shield against solar flares in a way that no aerospace vehicle was ever designed to. That'd be why deep space vehicles use water tanks and food for radiation shielding. The structure of the pressure vessel is about as effective at stopping solar flare radiation as a sheet of paper is at stopping a bullet. A solar flare releases enough radiation to deliver a lethal dose to an unprotected astronaut in minutes. The can is insufficient to protect against radiation of that intensity, but a meter of concrete reduces the dose received to something that would never be expected to harm a growing child.

The majority of the mass delivered to the surface of Mars will be structures and rocket fuel, not the food, water, breathing gases, or electrical power generation equipment you say you want more of. The structures mass of an ISS Destiny-based deep space habitation module is 9,000kg. The total dry mass is 23,000kg. Only 2,400kg are consumables. If you insist on sending aerospace vehicles constructed on Earth to service all habitation requirements, then the overwhelming majority of the tonnage delivered to the surface of Mars will not be food / water / breathing gases / electrical power generation equipment, it'll be packaging.

I completely agree with your assessment that food / water / breathing gases / electrical power generation equipment are a matter of life and death. The ability to build structures and obtain water and breathing gases from locally sourced materials dramatically reduces the mass requirement for structures and dramatically increases the availability of everything you say you want, as a function of the economics of delivering it to the people on Mars from Earth. If you can obtain your own building materials, water, and breathing gases on Mars, then it no longer has to be delivered from Earth.

With respect to your commentary about accidents in habitation modules, wouldn't it be great if we had ten more, just as good or better than the ones that we sent to Mars, built using materials that came from Mars since the materials sourced from Mars only cost what the equipment required to obtain them costs? Since sulfacrete can be re-melted and re-hardened, and it's mechanical strength actually increases when you do that, wouldn't that be a useful building material to have? From an economics standpoint, wouldn't it be great if we had reusable transports that we could repeatedly send to and from Mars orbit, assuming we had a permanent habitation solution on the surface of Mars?

A 3D printer is not that complicated. The software and microchips may be complicated, but the machine itself uses a heated print head and a few servos to do what it does. Mechanically, any spacecraft suitable for landing on Mars is far more complicated than a concrete bunker. I don't believe that everything will work perfectly, either, so I think that until we can build a habitat on the surface of the planet, obtain water, and obtain breathing gases, we won't be sending people in any significant numbers.

So what if it takes months of work to obtain the materials required to build a bunker on Mars? It takes months of work to build a spacecraft, six months to get it to Mars, and two years between launch opportunities. Why not start working on that robotic construction solution right now?

Dook · 2017-04-15 00:38:13

There's a lot of sulfur? There is a lot of iron oxide as well, and isn't there a lot of silicon too? If sulfur is 17% that means that 83% of the material you gather is waste and if you only find places with 10% sulfur that's a whole lot of work and wasted material moved and wear and tear on your rover.

The sulfacrete structure will shield better against solar flares than a tuna can habitat? But the link you provided for the 3D printer home showed that the roof was not made by the 3D printer. It had to be built later out of wood. What is the roof of your sulfacrete home going to be made from?

If sand bags are placed on top of the tuna can once it gets to Mars and it has it's water storage tank built in to the roof wouldn't the two of them provide good protection?

The majority of the mass delivered to Mars will be structure and fuel, not food, water, air, or power equipment? Well, I agree, but I would add in the water with the structure and fuel.

If I insist on sending vehicles constructed on Earth to be used as habitat on Mars? How else would we get humans from the Earth to Mars? Cryosleep coffins?

In my plan, the overwhelming majority of the tonnage sent to Mars will not be food, water, oxygen, or electric power equipment but packaging? Packaging is kind of necessary for space travel, isn't it? It's kind of necessary on Mars too, isn't it? How are you going to get your 3D printer to Mars? A sulfarocket?

Food, water, oxygen, and even electrical equipment are essential on Mars. They are so essential that you have to have reasonable backups and extra's. We have to be prepared for every plant to die. We have to be prepared for a Moxie to fail. We have to assume that there will be a month long dust storm and the solar panels will provide no power.

The ability to build structures on Mars means you can eliminate the tuna can hab from launch and send supplies? And then how do the people get from the Earth to Mars without a tuna can hab, in cryosleep?

The ability to obtain water on Mars means you can eliminate taking water from the Earth so you can send more supplies? The tuna can habitats will have a recycle water system so there would be no water lost. Brought water would be used on the plants in the greenhouse but it will be completely contained, none will be lost.

It would be great if we had more than one habitat as a backup? Sure, the greenhouse is a secondary habitat. It's warm, would have liquid water, and you could connect the Moxie line to it so it could have oxygen. The only bad thing is that it would rain every night inside. Also, the Long Range Rover could function as an emergency habitat for quite a while, weeks at least depending on how much oxygen is in the bottles.

Don't get me wrong, I think the sulfacrete thing is neat and eventually would be a pretty decent building material but it's not something the first settlement would do, or the second, or the third. That's way, way, way into the future because every crew that lands has it's own habitat. No material needed to collect. No centrifuge needed. No wiring for lights, or oxygen, or water.

Wouldn't it be great if we had reusable transports that stayed in orbit? Hmm, okay, the transport vehicle would have to be refueled each time it made it back to the Earth and then dock with a tuna can hab that has a new crew. Also the transports heat shield would have to be replaced and the heat shield would have to work twice, at Mars, then back at the Earth again, I don't think that's possible. I don't see the efficiency of it since the tuna can needs a rocket engine to land with so you can use that one to rocket the tuna can to Mars with and land with. You're not saving anything with a transport.

A 3D printer is not that complicated? I wasn't trying to suggest that the 3D printer would not work on Mars. What I was trying to say was that extra life support (an extra Moxie, extra electrical power, more food, more water) need to come first, second, and third, before something that makes neat Mars homes that no one is going to live in.

So what if it takes months of work to obtain the materials required to build a bunker on Mars? Why do all that work when no one is going to leave the tuna can for a bunker? Who is going to move into it, the cryosleep people?

Last edited by Dook (2017-04-15 00:39:43)

kbd512 · 2017-04-15 05:47:29

We need the 83% of everything else to make the concrete, in case that point wasn't clear. The heat extracts the sulfur from the sulfur bearing compounds, similar to how it's done here on Earth using the Frasch process, so there shouldn't be much wear and tear except on the rover's scoop.

The roof on the structure in the link was made from wood because it was cost effective and structurally feasible to do that for that particular structure. Mars requires pressurization for humans and plants, so the roof would be sulfacrete. The actual 3D print tool would vary in design from the tool used to build the house. It would remain outside the perimeter of the structure, mounted on a track, instead of in the center of the structure, mounted on a pedestal. The structure I had in mind is an oblate spheroid intended to transfer structural loads and withstand 14.7psi. The greenhouse variant would have lenses built into the roof to diffuse sunlight. The airlocks and lenses would come from Earth.

With respect to recycling, the waste water recycling systems aboard ISS have had their fair share of problems that caused them to fail completely. Thereafter, the crews required constant water replenishment from Earth until their waste water recycling system was fixed. If the Mars base is near a ground water source on Mars, the inability to recycle waste water is not a fatal event. There is no affordable way to deliver all the water required from Earth to Mars if water recycling equipment fails.

Every time an airlock is opened, the oxygen and water vapor are simply vented into space. That is how real airlocks work on every real spacecraft humans have ever created. The new CAMRAS CO2 scrubbers NASA is working on for the Orion capsule vents atmosphere and moisture into space during the amine swing bed's regeneration cycle. The engineers built features called "air save" and "water save" into the device to slow the rate of loss, but slowing the rate of loss is all that those features do. The new Paragon IWP ionomer membrane water processors are much lighter, simpler, and recover more water using far less electrical power than the equipment currently installed aboard ISS, but the disposable plastic bags that purify the water have short lives, can and have leaked, and the process is not 80% to 90% efficient. No 100% efficient recycling technology has ever existed. Losses are inevitable.

Tuna cans can be buried, but then you need earth moving equipment. At some point the astronauts or colonists may want to leave, unless your plan is for them to die on Mars. Then two tuna cans are required unless you're going to dig up the buried tuna can to fly it back to Earth. The tuna cans are also rather expensive. The ISS Destiny tuna can cost $1.38B, but we'll pretend a Mars habitat will only cost $100M. Even at $100M per copy, the cost of the tuna cans will quickly surpass the cost of the reusable $100M Falcon Heavy rockets.

A tuna can doesn't have to take someone from the surface of the Earth to the surface of Mars and back again. A fusion driven rocket can deliver humans to Mars in 90 days, so consumables for 90 days are required if habitats and consumables are already available on Mars. This is something NASA is currently funding to get humans to Mars faster using far less fuel than chemical or nuclear thermal rockets use. If reusable LOX/LH2 or LOX/LCH4 landers can get you to the surface where pre-built habitats are available, then tuna cans are not required or desirable for living on Mars.

MSNW LLC Space Propulsion Publications

When the US Navy wanted me on a ship home ported in Japan, they didn't send a transport ship to San Diego to come pick me up so they could then send the ship back to Yokosuka Naval Base. They put me on a Boeing 747 that landed at Narita and then I took a bus to the base. The Falcon Heavy and Fusion Driven Rocket are the equivalent of the Boeing 747, the reusable lander is the equivalent of the bus, and the sulfacrete habitat on Mars is the equivalent of Yokosuka Naval Base.

Dook · 2017-04-15 11:03:07

I thought the information on the sulfacrete said that the best mixture was 50% sulfur? So, you have to separate the sulfur from the other elements to then combine them in the amounts you want and discard material.

There wouldn't be much wear and tear on the rover, except the scoop? How about on the electric motors?

The sulfacrete home would have an airlock sent from the Earth? And the oxygen monitoring system? The CO2 removal scrubber? The water recycling system?

The ISS has had problems with it's water recycle system? Sounds like someone made it more complex than it needed to be. All you have to do is filter the shower water and urine and change the filters periodically. If the filters are made of metal you could take them out and clean them somehow. Maybe take them outside on Mars and spray them with pressurized CO2 and then set them in front of a solar mirror at high noon?

Now, this filters and re-uses all of your shower water and urine. Feces would have to be put into plastic bags and microwaved to get the water out as vapor, then a dehumidifier inside your habitat could condense the water vapor back to water. This is another reason why we can't have multiple homes on Mars too soon, the crew needs to all use one bathroom/shower so we're keeping our water use to two locations, the hab and the greenhouse.

There is no affordable way to ship water to Mars if water recycling fails? That's exactly why you don't make it more complicated than it needs to be.

Every time an airlock is opened you will lose some oxygen and water? Correct, it's not a lot but it is a loss that will add up over time. If we have zeolite panels placed outside on Mars and left for a few weeks then brought inside the greenhouse and heated with a solar mirror they will vent water vapor and CO2 into the greenhouse. It's not a lot but we're not losing a lot either. It will rain every night inside the greenhouse and water will run down the sides into trays at the bottom of the greenhouse sides. So, by putting some water vapor into your greenhouse you are getting water. You want as few airlocks as possible to keep evaporated water loss to a minimum, not one for every personal home on Mars.

Tuna cans can be buried? I did not suggest burying them, just putting sand bags on top.

Zubrin says that a solar flare in space would expose a crew in space to about 38 rem. If they go into the built in shelter it would be about 8 rem. They get about 10 rem outside on Mars and 3 rem inside the Mars tuna can. I think you're over exaggerating the danger. No matter what kind of home they live in the crew is going to be exposed in the greenhouse at times anyway, and when they are working outside, and in the rover. The mission has danger. If they're not up to it they don't have to go.

At some point the colonists may want to leave Mars? No way. They go to stay.

A fusion driven rocket can get people to Mars in 90 days? So the people will have less than a tuna can for 90 days? I think you can squeeze another two people in a Zubrin tuna can if you get rid of the science station but that's a total of six people. How many were you expecting we would be able to move with your fusion rocket?

Why have a transport in space when every crew delivered to the surface of Mars will need to land with it's own rocket engine? So, they can use that same engine to leave earth orbit. No transport needed.

All of this stuff isn't going to make things happen quicker. It's going to make things happen slower.

Last edited by Dook (2017-04-15 11:09:47)

kbd512 · 2017-04-15 16:16:49

Here's a fluff animation video from NASA Space Technology Mission Directorate that showcases many of the enabling technologies NASA is working on right now:

Game Changing Development Mission Animation

You're right about 50/50 being the best mix for sulfur concrete. I never said there would be no waste or that the process would convert all of the Martian regolith into Martian concrete with 100% efficiency. That doesn't happen here on Earth, but it's never been a problem here. Separation of the Sulfur requires heat. Once the Sulfur melts, we collect the molten Sulfur in a tank. The molten Sulfur is transported by tanker trucks and tank cars by rail here on Earth. A robot can transport the molten Sulfur on Mars.

The electric motors for motive transport are quite reliable (last for many years) and efficient (convert 90% to 95% of the input electricity into mechanical force, instead of waste heat). That type of performance is fairly typical of what we use right now and why electric cars / trucks / buses are feasible substitutes for fossil fuel powered vehicles.

The complicated electrical, mechanical, and electro-mechanical systems such as computers, airlocks, nuclear reactors, and environmental controls like CO2 scrubbers and waste water recycling systems would still be manufactured here on Earth. These components are small and light weight compared to the pressurized structures they provide services for.

Regarding the technology ISS uses for water recycling, you're welcome to show NASA how it should be done if you have better ideas and a working prototype unit. Do you have a water processor that works in microgravity? Regarding water removal from feces, NASA and ROSCOSMOS use vacuum desiccation. If you know how to un-complicate such systems, I'm certain NASA would cut you a check for your efforts.

For the greenhouse to produce enough food to justify the cost of the project, you're talking about many tons of water. If you can obtain that water from Mars and build the greenhouse using Martian materials, then the greenhouse will be a lot less expensive.

Sand bagging the tuna cans still requires Earth moving equipment unless the astronauts are outside in space suits filling sand bags with entrenching tools. That could work, but it'd be a slow process. We do that here on Earth and as long as the astronauts were wearing mechanical counter-pressure suits, it should work on Mars, too. If you think water loss from airlocks is bad, make a half dozen people fill sand bags for 8 hours a day and watch how fast they go through their irreplaceable water, assuming no water is locally sourced from Mars.

Dr. Zubrin may think a lot of things, but last time I checked his PhD was in aerospace engineering. He doesn't know anything more about radiation than what he's read and probably ignores any information that doesn't agree with his beliefs, much like the climate change people ignoring the fact that their own data doesn't agree with their own climate models. Therefore, we're going with what the people who have MD's in nuclear medicine say over what a PhD in aerospace engineering says. Dr. Zubrin's remarks on radiation was also directed at people who are going to Mars for one exploration mission versus two or three tours aboard ISS. In that context, I agree with his remarks because actual data gathered on multiple flights to Mars indicate that the total dosage received is the same as two or three 6 month tours aboard ISS. However, this thread is about colonization and you stated that anyone sent to Mars is a permanent resident.

Radiation doses are cumulative and the damage done to living tissue is also cumulative. The GCR radiation may be a small dose compared to the solar flares, but you're taking that dose 24/7 if you live in a tuna can for the rest of your life. The tuna can actually makes the GCR radiation worse as a function of the secondary radiation received from the thin aluminum pressure vessel that increases the effects of the GCR's by producing secondary particle showers. If you live in a bunker made from meter thick regolith, then the bunker stops most of that and virtually all of the solar flare radiation. Also, not all forms of radiation do the same amount of damage to living tissue. The ultra high energy ions (GCR's) are more destructive to critical human tissues like the brain than low intensity X-rays and gamma rays. Ions with GCR energy levels created in laboratories were found to cause severe and persistent brain damage in mice, so less exposure is better.

NASA is working on development of Boron Nitride NanoTube (BNNT) fibers for constructing lightweight pressure vessels that reduce, rather than increase radiation exposure. BNNT fabric is an electrically and thermally insulating material that's very light and has superb radiation attenuation properties against the types of GCR radiation that do the most long term damage. It'd still require a water tank solar flare shelter, but it'd also be light enough to affordably ship many copies thereof to Mars. If Mr. Musk is right about the ultimate cost of using SpaceX's reusable Falcon Heavy rocket, then the cost to ship a kilogram of anything to Mars is $50,000 (that's only $50M to ship 264 gallons of water). If NASA's BNNT pressure vessel efforts are successful, then your tuna can concept would provide the radiation protection required with minimal sand bagging.

I guess I already know what your answer will be, but does $50M seem like a reasonable price to pay to deliver 264 gallons of water to Mars?

Edit:

Regarding the fusion driven rocket, I expect that 12 people could be transported to Mars if they're not coming back. That's based on the consumables required for 6 astronauts going to and from Mars and the habitable pressurized volume that an inflatable habitat module such as the Bigelow Aerospace B330 is expected to provide. The mass of the payload is approximately 30t, compared to the 61t that the MSNW FDR was originally intended to deliver to Mars in 90 days. That means the rocket requires even less fuel.

The propellant accounts for less than 50% of the total mass of the spacecraft, but the propellant is expensive pure Lithium metal and the required 35t worth of Li propellant will cost between $9M and $10M. That's still pennies on the dollar with respect to what would be required using chemical or nuclear thermal rockets to achieve a 90 day transit time.

A reusable Cygnus spacecraft using expendable inflatable heat shields (HIAD) would transfer the colonists from Low Mars Orbit to the surface of Mars. Each B330 would deliver the HIAD required for reentry. After the FDR delivered the colonists to Mars by transferring them to Cygnus, it would return to Earth using a minimum energy trajectory. The FDR's payload would be approximately 9t lighter than when it left Earth.

The total mass of the fully fueled fusion rocket and habitat module is around 80t and requires 2 Falcon Heavy launches. Thereafter, a single Falcon Heavy would deliver an additional 12 colonists to Earth orbit with more Lithium fuel for the rocket.

Commodity chemical rockets would transfer cargo on minimum energy trajectories every two years using reusable SEP upper stages, mostly complex machinery like life support equipment and rocket engines, electronics, and medical supplies. By economic necessity, the building materials, breathing gases, food, and water would all come from Mars. The rocket fuel to power the reusable Cygnus transfer vehicles would also come from Mars.

The initial plan is to launch 4 Falcon Heavies per opportunity, delivering 12 new colonists and approximately 60t worth of cargo between the 3 SEP powered cargo flights.

Last edited by kbd512 (2017-04-15 19:44:27)

Dook · 2017-04-15 17:49:31

Electric motors are quite reliable? They are but if you're using them everyday that's going to wear them out quicker than not so that means more spare parts shipments.

All of the electrical power cords, airlock, CO2 scrubber, water recycling for your homes still have to be made on the Earth but they are lightweight? Okay, they are somewhat light weight but all of that is already in the tuna can lander.

I'm welcome to show NASA how it's done? You can't fill a cup that's already full. No one is going to show NASA a thing, not even when you get it right, like Zubrin.

Filtering urine removes the particles but doesn't get the salt out, so if you are unwilling to use the salty water in your food you would have to boil it to separate the water and salt.

Do I have a water processor that works in microgravity? Nope, but it seems neither does NASA.

For a greenhouse to produce enough food you're talking about many tons of water? Yes, we need a few tons of water, not many tons. We're not going to use sprinkler system, we would use hydroponics and buckets to water our greenhouse plants.

We don't explore to make money. We're not going to go to Mars to make money. It's all cost, no return. How exactly Elon Musk is going to get 1m people to Mars and make money off of it is beyond me.

Now, about the greenhouse, the largest greenhouse I think a small settlement can reasonably assemble is about 100 feet across and 25 feet high. I water my fruit trees with a hose once a week all summer long, maybe 10 gallons each, but mine are full grown semi-dwarf. You could probably get by watering semi-dwarf fruit trees about two gallons every two days if the water is put directly to the roots with a drip irrigation line. So, if we have 50 trees, that's 200 gallons a week but the water will evaporate each day and condense on the inside of the greenhouse and would run down the inside walls to trays along the bottom row of panels. The trays would have irrigation lines going to the trees.

So, you wouldn't be losing any water, it just kind of circulates on it's own. Also, each tree would be planted in a plastic tub so the water can't sink too far into the Mars regolith.

Sand bagging the tuna can still requires Earth moving equipment? No, two guys climb up on top with the bags and drop two ropes, two guys at bottom fill the buckets with sand, guys up top pull up the ropes. It might take about three hours.

People filling sand bags will go through their irreplaceable water quickly? All the water they use is not discarded, it's filtered and re-used.
Zubrin doesn't know anything about radiation? Maybe he went and talked to the people who had expertise in that area? I don't know where he got his numbers. If you're right, then no people can ever go to Mars. They will all die in transit or die doing work outside their sulfacrete home.

Less exposure is better? Absolutely. Is there a difference between 1: a foot of sand (in bags on the roof) and a foot of water (in the ceiling of the tuna can) and 2: just a foot of sulfacrete?

Does $50m seem like a reasonable price to pay to deliver 264 gallons of water to Mars? Depends. If we're just going to send the water and have it impact the Mars surface, then no. If it's going to supply a settlement that had an accident and lost their water and they need an urgent supply, then yes.

Dook · 2017-04-15 18:58:27

I don't like the idea of having separate homes on Mars for a first settlement. I know you guys want spacious beautiful apartments with big windows overlooking Olympus Mons, that's not settlement, that's 500 years in the future.

Better than having separate homes would be a buried central complex with multiple apartments but with a common kitchen and a common bathroom. They could spray passageways leading out from this complex for future connection to another future built complex. These passageways could be sealed up with a sulfacrete wall until they were needed, you could just tear it down from inside with a hammer.

The area for this buried complex would be dug out, go down maybe just over one story, then the dug out material could be processed for it's sulfur so you wouldn't really be driving the rover that far from the base.

You would need a large aluminum tank to put the material in. I assume you would have the tank be built in as a part of the nuclear reactor. Then you would have to use a long handle scoop to get the molten sulfur. You could just toss the sulfur in a long pile until you had enough. Then you would have to use another scoop to remove the other material, that would require a lot of work every day. The amount of sulfur you would need is pretty incredible.

Before spraying you would mix in half sulfur and half other into the aluminum tank, let it melt, you don't need the 3D printer, just a well insulated hand sprayer (1/2" wide aluminum tubing) would work. I think the sulfacrete home used aluminum screen to spray the sulfacrete onto so you would set your screen up with stakes and start spraying. Not sure what the hose from the molten sulfur tank to the hand sprayer would be made out of.

Once the complex is finished it could be buried with the not used material. You could also spray a circular foundation around the top of the buried complex and build your greenhouse on it so workers could just go directly from the complex to the greenhouse without ever going outside.

I don't know, there are some good things about it.

Last edited by Dook (2017-04-15 18:59:46)

Oldfart1939 · 2017-04-15 19:35:20

kbd512-

Just a point of information regarding Dr. Zubrin's degrees (plural!): his Ph.D. is in Nuclear Engineering, along with an M.S. in the same field; he also has an M.S. in Aerospace Engineering. All advanced degrees are from University of Washington.

kbd512 · 2017-04-15 21:33:40

Oldfart1939 wrote:

kbd512-
Just a point of information regarding Dr. Zubrin's degrees (plural!): his Ph.D. is in Nuclear Engineering, along with an M.S. in the same field; he also has an M.S. in Aerospace Engineering. All advanced degrees are from University of Washington.

A nuclear engineer doesn't study the effects of radiation on living organisms, whereas a MD in nuclear medicine does. If you never visited a gynecologist for erectile dysfunction, then there's a good chance that you understand the concept of specialization. A nuclear engineer knows more than the average person about the health effects associated with radiation exposure, but the health effects from radiation exposure that come from nuclear materials and nuclear reactors are different than the health effects that ions from particle accelerators or supernovae produce.

Unless our government did classified studies on the health effects associated with GCR's, then that information wasn't available or wasn't well understood until very recently. Dr. Zubrin either had access to classified information and then made statements that contradict the conclusions that medical researchers have recently made or he was speaking from a position of ignorance about what the health effects from GCR exposure actually were. Either way, I'm not taking the opinion of one nuclear engineer who is not a medical doctor on health-related issues associated with GCR exposure over the opinions of multiple medical doctors (EDIT: medical doctors whose opinions are based on actual observed evidence from experiments performed as opposed to supposition of what the effects should be as a function of the cumulative dose and dose rate over the exposure areas).

Apart from the case of Dr. Anatoli Petrovich Bugorski and the Apollo astronauts, few other humans have been substantially exposed to light speed GCR's for any significant amount of time. The ISS crew members occasionally report seeing flashes of light. Dr. Bugorski was exposed to a proton beam from a particle accelerator, as opposed to the heavier ions encountered in deep space. The fact that he didn't die in a matter of hours or days after having 3000 grays worth of radiation shot into his brain is something of a minor miracle. However, Dr. Bugorski's injuries are not what I would call trivial. The brain tissue in the path of the beam was completely destroyed, he lost hearing in one ear, half of his face is paralyzed, he said he had cognitive function impairment after the incident, and he had seizures later in life.

The intensity of GCR's is nowhere near what that particle accelerator produced, that we know of, but those ions are constantly flying around in space at relativistic speeds. The length of exposure that a Mars exploration of colonization mission will experience is far longer than anything anyone else has experienced. Anyone who says they know exactly what the results will be is lying, but initial indicators don't look too rosy.

It's not an absolute show stopper, but it's a far more serious issue than the hand waving aerospace and nuclear engineers would ever admit to, mostly as a function of their complete ignorance about this type of radiation and their fervent desire to build the rockets that send humans to other planets. Unless they work on particle accelerators or are astronauts, ions with the energies in the gigavolt range aren't frequently encountered by aerospace and nuclear engineers. The greatest portion of the radiation dose that ISS astronauts receive is GCR's, in case anyone was wondering. Most of the radiation from solar flares is absorbed by that giant magnetized plasma shield surrounding the Earth above ISS's orbit. I don't fault anyone for taking risks to explore, but there's a fine line between acceptance of calculated risk and bravado.

Last edited by kbd512 (2017-04-15 21:42:40)

kbd512 · 2017-04-16 03:51:52

Dook wrote:

Electric motors are quite reliable? They are but if you're using them everyday that's going to wear them out quicker than not so that means more spare parts shipments.

The electric motors on Curiosity have been in use for years now and they still work, 24/7. The motors in the previous rovers still work, too, but the electronics and solar panels have been severely degraded by the environment. I'm a little surprised that the solar panels on MER-A and MER-B held up as well as they did in the bitterly cold and abrasive Martian environment. The engineers even managed to reload the software after MER's chips were damaged by the radiation.

Dook wrote:

All of the electrical power cords, airlock, CO2 scrubber, water recycling for your homes still have to be made on the Earth but they are lightweight? Okay, they are somewhat light weight but all of that is already in the tuna can lander.

Let me put it this way. If the CO2 scrubber is merely an appliance plugged into an outlet instead of a piece of full-on aerospace hardware in an aluminum chassis that must be secured in a rack designed to withstand multiple G's and vibration, then that generally reduces the cost and weight of the unit in question.

Take a look at these PDF's and tell me if you think a standalone unit could be lighter:

Amine Swingbed Payload Testing on ISS

Carbon Dioxide Removal Technologies for U.S. Space Vehicles: Past, Present, and Future

CAMRAS is the lightest and most compact long-life / long-duration CO2 scrubber.

Dook wrote:

I'm welcome to show NASA how it's done? You can't fill a cup that's already full. No one is going to show NASA a thing, not even when you get it right, like Zubrin.

Dr. Zubrin advocated for using local resources to make the mission affordable and feasible using current rocket technology. I agree with him. Using Martian oxygen, water, and building materials is the only affordable way to do Mars colonization. Even at that, governments will have to subsidize the operation for many years to come. I want the subsidy to be something trivial. Our government won't care about spending a couple billion dollars every year so NASA can do Mars exploration and colonization in cooperation with private companies.

Dook wrote:

Filtering urine removes the particles but doesn't get the salt out, so if you are unwilling to use the salty water in your food you would have to boil it to separate the water and salt.
Do I have a water processor that works in microgravity? Nope, but it seems neither does NASA.

True. So, how would you do it better than NASA has managed thus far?

Dook wrote:

For a greenhouse to produce enough food you're talking about many tons of water? Yes, we need a few tons of water, not many tons. We're not going to use sprinkler system, we would use hydroponics and buckets to water our greenhouse plants.

How many plants are we talking about? Ballpark it and refine your estimates from there.

Dook wrote:

We don't explore to make money. We're not going to go to Mars to make money. It's all cost, no return. How exactly Elon Musk is going to get 1m people to Mars and make money off of it is beyond me.

Agreed, but we're talking about colonization here. Colonization may be adventurous, but it's not quite the same as a government approved exploration expedition. There has to be some eventual payoff. Maybe it's just an eventual "second Earth". Mr. Musk has only figured out how to get a million people to Mars. He's basically stated that he has no clue about how to keep them alive once he gets them there and that part of the operation is someone else's responsibility.

Dook wrote:

Now, about the greenhouse, the largest greenhouse I think a small settlement can reasonably assemble is about 100 feet across and 25 feet high. I water my fruit trees with a hose once a week all summer long, maybe 10 gallons each, but mine are full grown semi-dwarf. You could probably get by watering semi-dwarf fruit trees about two gallons every two days if the water is put directly to the roots with a drip irrigation line. So, if we have 50 trees, that's 200 gallons a week but the water will evaporate each day and condense on the inside of the greenhouse and would run down the inside walls to trays along the bottom row of panels. The trays would have irrigation lines going to the trees.

Most of the water evaporates, but plants also retain absorbed water as they grow. Approximately how much do your trees weigh?

If water cost $50M for every 264 gallons, wouldn't it be a lot less expensive to obtain water from local ice deposits?

Nowhere is it written that locally obtained water can't be recycled. It only seems prudent to try, but if that fails for whatever reason then a local ice deposit could really save the day.

Dook wrote:

So, you wouldn't be losing any water, it just kind of circulates on it's own. Also, each tree would be planted in a plastic tub so the water can't sink too far into the Mars regolith.

If you seldom open an airlock and the greenhouse is truly sealed, then I'm inclined to agree. The water should be trapped in the miniature ecosystem of the greenhouse.

Dook wrote:

Sand bagging the tuna can still requires Earth moving equipment? No, two guys climb up on top with the bags and drop two ropes, two guys at bottom fill the buckets with sand, guys up top pull up the ropes. It might take about three hours.

Two guys could do that in three hours? I wish. Dr. Zubrin's tuna cans were 8.4m in diameter, that's 26.39m in circumference, and 11.1m tall. It's not just the top that requires sand bagging. If you could somehow lower the habitat module to the surface by getting rid of the empty fuel tanks and rocket engines, then it's still a good 6m in height.

Dook wrote:

People filling sand bags will go through their irreplaceable water quickly? All the water they use is not discarded, it's filtered and re-used.

Sweat is recycled in Space Shuttle EMU's, but EMU's also weigh 275 pounds. Even at .38g, such a task would require peak physical fitness. MCP suits are designed to permit perspiration to sublime into space through the fabric of the suit without the need for an environmental control system to remove excess moisture from the suit. MCP suits are far lighter at 50 to 60 pounds and provide far greater mobility than impermeable membrane space suits of the EMU variety, reducing the caloric expenditure required to simply move around.

Dook wrote:

Zubrin doesn't know anything about radiation? Maybe he went and talked to the people who had expertise in that area? I don't know where he got his numbers. If you're right, then no people can ever go to Mars. They will all die in transit or die doing work outside their sulfacrete home.

The cumulative radiation exposure is a problem, but that doesn't mean nobody can ever go outside. The damage that radiation does is specific to the type (alpha, beta, gamma, neutron, ion) as a function of energy delivered, dose rate, dose duration, and the part of the body that receives the dose. The Martian atmosphere and the planet itself help with shielding.

The 6 month trip to Mars is 250 milliSieverts. The six month trip back to Earth is another 250 milliSieverts. A 500 day surface stay is approximately 500 milliSieverts. The maximum permitted career radiation dose for an astronaut is 1 Sievert, so one conjunction class Mars exploration mission brings the astronaut to his or her career radiation exposure limit. The LD50/30 (expected to kill approximately 50% of those exposed within 30 days) for humans is 4 to 5 Sieverts if the radiation is received over a short period duration.

In simple terms, the expected types and doses of radiation received just mean that living structures need to be well shielded. A meter of Martian regolith is substantial shielding and approximately 1.5m of regolith shielding would be required to reduce the dose rate to approximately 5rem/yr, which corresponds to the occupational dose rate limitation for adults. A pregnant woman is permitted to be exposed to .5rem over the entire duration of the pregnancy.

Dook wrote:

Less exposure is better? Absolutely. Is there a difference between 1: a foot of sand (in bags on the roof) and a foot of water (in the ceiling of the tuna can) and 2: just a foot of sulfacrete?

The Martian atmosphere provides shielding equivalent to something between 30g/cm^2 and 40g/cm^2, dependent upon where you are on the surface, and the planet blocks half of all radiation that would be received in deep space. The good news is that the Martian atmosphere blocks most of the brain damaging heavy ions and dramatically reduces the effects of solar flares compared to deep space. The bad news is that some of the radiation still makes it through. The higher in elevation you go, the less shielding the atmosphere provides, and the Martian atmospheric density is substantially variable compared to Earth's atmospheric density. To adequately shield against the ions that make it through, you need 1.5m of regolith shielding to meet that 5rem/yr occupational limit.

A foot of concrete or a foot of water would certainly help, but it would not reduce radiation exposure to levels considered occupationally acceptable here on Earth. You need to start thinking in terms of meters of shielding. Do you understand why I wanted to use a tunnel boring machine to vertically emplace habitat modules? Women and children require more radiation protection than men do. You need multiple meters of shielding to produce a radiation environment considered to be acceptable for pregnant women.

Dook wrote:

Does $50m seem like a reasonable price to pay to deliver 264 gallons of water to Mars? Depends. If we're just going to send the water and have it impact the Mars surface, then no. If it's going to supply a settlement that had an accident and lost their water and they need an urgent supply, then yes.

I just think we're going to handily exceed the cost of obtaining water from local sources rather quickly at those prices, which presumes that Mr. Musk knocks the cost down to $1,000/kg. Falcon 9 FT currently costs $2,719/kg to LEO. A heated well pipe that extracts liquid water from frozen regolith is not exactly bleeding edge technology. It's obviously one more piece of equipment that can break or malfunction, but if water tanks are filled ahead of time then the risks associated with equipment malfunction or damage are reduced and every gallon of water extracted past what the machine weighs is money in the bank. If we can't figure out how to reliably melt ice, then we probably shouldn't go.

Last edited by kbd512 (2017-04-16 03:58:31)

louis · 2017-04-16 07:06:45

On separation - there are pros and cons.

A disastrous pressure failure or fire in a single central complex could mean death for everyone.

That's why I like the idea of having separate Farm and Industrial Habs, as well as an inflatable main accommodation Hab for the first mission. Your lander vehicles and a Rover then represent additional emergency accommodation as well. I also like the idead of spreading around oxygen and water supplies over the landing complex, so that a fire or pressure failure in one location doesn't wipe out life support.

That said, I think there are strong arguments for having everyone essentially working out of the same central hab.

Oldfart1939 · 2017-04-16 10:50:57

Louis-

I agree about separation of habs by functionality. There could be a couple living habs, an industrial hab, and several agricultural habs. When I speak of several ag habs, one for animal husbandry, and a second for vegetables, fruits, trees, etc. A disastrous fire could occur in the industrial sector, and cooking food can give rise to fires.

Dook · 2017-04-16 11:24:47

Electric motors can work for years? Okay, so to expand your settlement you admit that there are things that you have to send from the Earth like more pressure doors for all the homes but you don't want to send other things like one or two extra electric motors for the rovers?

The items made on Earth that you need in your Mars homes are small? They are. You still haven't answered the question, why would someone leave the tuna can, that already has everything, for a Mars dirt home?

I will answer it for you since you don't want to reveal your "agenda". You think the Mars home will be more luxurious than living in a tuna can. If you went to Mars you would want to live in a home that is nicer than you can have on the Earth. People who think that way are not going to go to Mars once they realize they will be living in somewhat cramped quarters forever, will have limited food choices, they can never have kids, and they can't ever return to the Earth.

Manufacturing on Mars is the only affordable way to do Mars colonization? Profit once again. We don't explore for profit. We're not going to colonize Mars for profit. Being able to manufacture tiny things like brackets with a 3D printer is not going to get you more oxygen, more water, or more food on Mars and those things are going to limit colonization, not habitat. Every new settler is going to land in a perfect habitat.

Our government won't care about spending a couple billion dollars a year so NASA can do exploration and colonization with private companies? NASA gets about $17 billion a year every year. I think NASA should deploy three more Hubble telescopes so we would have a space interferometer and be able to see farther and with more detail. After that, I think all of NASA's budget should go to a Mars sample return mission, then three Mars Direct exploration missions, then Mars Direct style settlement.

How would I recycle water better than NASA? My system wouldn't cost $1m or whatever it costs, and it would not break daily. It would have a DC water pump for the shower and filters. For the urinal, you would piss into a plastic can, use a hand pump to pump the urine through a particulate filter in a stainless steel can, once the can is full someone would take it to the greenhouse and use solar cookers/reflectors to boil out the water. Then use a little water and a hand scrub pad to get the salt off the can. No electronic monitoring equipment needed.

How many plants are we talking about for a greenhouse on Mars? Don't know. I can't even ballpark it at this point until I know how big of a greenhouse I can take. The greenhouse needs to be as big as possible, it's more important than having a hundred homes on Mars. Even so, without a doubt hydroponics would be the most successful but it can only grow certain plants. And, having a fish tank and algae tank would provide protein and 4 chickens would provide eggs.

There has to be some eventual payoff for colonization? No, there doesn't. People on the Earth would be ecstatic and want to check daily on how the colonists were doing. I would bet that NASA's budget would actually grow if they colonized Mars.

Mr. Musk has only figured out how to get a million people to Mars? No, he hasn't. He's proposed a fantasy that some of you have bought into.

How much do my trees weigh? When I bought them they weighed about 25 lbs, I guess, and they had a clump of dirt on the roots. Yes, trees retain water as they grow.

How much do my trees weigh now? Don't know, if I had to guess I'd say they were maybe four times heavier than when I bought them, but not all of that is water. For vegetables any water retained by the non-edible parts of the plant stays in the greenhouse as compost. Edible vegetables that retain water transfer the water to people.

Wouldn't it be a lot less expensive to obtain water from local deposits? Yes, but it has to be reasonable. It's not reasonable to drive far from the base, place a microwave, build a tent, power the microwave (using what power source?), then use some small pump to get some water vapor into some kind of container. All of that will get you a few drops. And, if your rover breaks down, you're dead.

Or, you can drive far from the base and use some drilling equipment to get dirty ice that you put into buckets and bring them inside your pressurized rover to warm it up. The ice melts, the dirt settles and you have maybe a few cups of water. Can you get some water this way? Yes. Not enough to really do anything with and if your rover breaks down far from base you lose people and you lose your rover.

If we had large zeolite panels, placed them out on Mars for a month, brought them inside the greenhouse and used the solar cookers to heat them they will outgas CO2 and water vapor. It's not a lot but we shouldn't be losing a lot either, unless we're wasting our water to make rocket fuel.

The greenhouse itself, once finished and warms up, will outgas some water vapor from the Mars regolith, so, just by doing that you get a water gain, it would not be a lot but it would be some.

Two guys can't fill sand bags in three hours? Not two guys, four guys, two on top and two on the ground. They could pre-move a large pile of sand near the habitat. Also, I don't see the need for putting the material into sand bags, they can just pour it out on top of the habitat and then, when they are done, cover it with either a tarp or some kind of thin cloth and hold it down with rocks.

The task would require peak physical fitness? They don't need to be in peak physical fitness. The people that go will be fit or they don't get selected to go, can't have lazy people on Mars. If it's too much work then they will work a few hours each day on it.

They need radiation shielding? They do. How long is it going to take your crew to get together all the sulfur and use a screen to sift the aggregate material to the correct size and then assemble all the aluminum screen to spray the sulfacrete onto, and then install all the monitoring equipment, connect the Moxie line to it, run the power line, and set up the water system? The top of my tuna can is covered in regolith in three or four days.

Also, does the Red Dragon have water shielding?

We need 1.5 meters of shielding? Did you add in the water shielding that is already in place on the tuna can? I don't see us being able to move enough material to get 1.5 meters on top of the tuna can, maybe two feet of regolith might be it.

We need multiple meters of shielding to make it safe for pregnant women and children? There aren't going to be any pregnant women or children at the first settlements. The men will have to get vasectomies.
These problems affect your plans much more than they affect mine. You want the first settlers to have big luxurious homes on Mars and families and manufacturing and somehow return a profit to Elon Musk. It's just not going to happen that way at first because we don't have cryosleep or warp drive.

A heated well pipe could extract water from frozen regolith? Hmm. Now that idea has some potential. Your settlement would have to be placed in an area with thick ice. You could do it right at your base. You wouldn't have to go that deep, maybe 100 feet down, so use ten 10' long drilling pipes. The water would not come up out of the well. The drilled hole would fill with Mars atmosphere at first, raising the pressure slightly, helping ice turn to water instead of vapor. You could dig the wall, then build your greenhouse over the well, then heat the well to make water.

You would then need a Grundfos AC/DC submergeable well pump and 80 feet of 1" poly pipe (you don't want the well pump near the bottom because it will pick up dirt). The pump needs 4 amps, 30-300 volts DC, so you would have to have a certain section of thin solar array just for this purpose. The pump will put out about 3-5 gpm depending on which pump you use.

You would have to be careful not to get the well too hot or you would melt the poly pipe. I wonder if just using a fan to blow warm greenhouse air down into the well would be enough?

You would only get so much water before it would run dry because you're only going to be able to heat the ground out to about a few feet. I don't know, maybe you could get a couple hundred gallons. That would work, I'm just not sure it's really worth it.

Another option would be to not use a well pump at all and instead use zeolite cylinders. Super heat your well, drop the zeolite cylinder into the well on cables, pull them up and use solar reflectors to steam out the water inside your greenhouse. That would take longer but you could really use a lot more heat in the well and get more water in the long run.

All of this would have to be done near your base to use the heat available from the nuclear reactor so it would get you some water, not sure exactly how much.

Dook · 2017-04-16 11:37:14

louis wrote:

On separation - there are pros and cons.
A disastrous pressure failure or fire in a single central complex could mean death for everyone.
That's why I like the idea of having separate Farm and Industrial Habs, as well as an inflatable main accommodation Hab for the first mission. Your lander vehicles and a Rover then represent additional emergency accommodation as well. I also like the idead of spreading around oxygen and water supplies over the landing complex, so that a fire or pressure failure in one location doesn't wipe out life support.
That said, I think there are strong arguments for having everyone essentially working out of the same central hab.

A fire in a central complex could mean death for everyone? If a fire happens during the day the people would be awake and be able to put on oxygen masks and fight it. If it happens at night a smoke detector would awaken them and they would put on oxygen masks and fight it.

What's better, one person fighting a fire or pressure failure alone in their isolated home while the others sleep quietly in their homes and don't hear a thing or four people together fighting a fire in their complex?

In my ideas, the crew spends almost all of their time in the habitat and greenhouse.

In your ideas the crew spends almost all of their time away from the habitat getting material to try and make more homes and rocket fuel.

Dook · 2017-04-16 11:44:15

Oldfart1939 wrote:

Louis-
I agree about separation of habs by functionality. There could be a couple living habs, an industrial hab, and several agricultural habs. When I speak of several ag habs, one for animal husbandry, and a second for vegetables, fruits, trees, etc. A disastrous fire could occur in the industrial sector, and cooking food can give rise to fires.

Almost all cooking would be microwave steaming. They would probably have boiled eggs daily.

Once in a while you would kill a chicken or tilapia fish and use a solar reflector/cooker in the greenhouse to cook it. No methane cooking needed.

The greenhouse can't catch fire. It could have a massive pressure leak if an asteroid goes through a panel but they would have one or two extra panels just in case.

The habitat could catch fire. The crew would don oxygen masks, turn off the main circuit breaker, then put out the fire.

The habitat could also have a pressure leak. They could be fixed with some type of sealant. If there was a massive pressure leak they would have to abandon the habitat and live in the greenhouse and long range rover.

kbd512 · 2017-04-16 18:06:41

Dook wrote:

Electric motors can work for years? Okay, so to expand your settlement you admit that there are things that you have to send from the Earth like more pressure doors for all the homes but you don't want to send other things like one or two extra electric motors for the rovers?

I'm not under any illusion that substantial support from Earth won't be required. It can be affordable support limited to replacement parts for high technology items or it can be shipping things that already exist on Mars. It won't be cheap, either way, but by maximizing the use of available local resources it doesn't have to be prohibitively expensive. The rovers would have multiple electric motors, so a failure of one motor would not disable the rover. Similarly, multiple power plants are required to ensure that a failure of one power plant doesn't lead to loss of electrical power.

Dook wrote:

The items made on Earth that you need in your Mars homes are small? They are. You still haven't answered the question, why would someone leave the tuna can, that already has everything, for a Mars dirt home?

You can either ship tuna cans large enough to hold a significant number of colonists or you can ship the components required to sustain life support functions and use local resources for building materials.

Dook wrote:

I will answer it for you since you don't want to reveal your "agenda". You think the Mars home will be more luxurious than living in a tuna can. If you went to Mars you would want to live in a home that is nicer than you can have on the Earth. People who think that way are not going to go to Mars once they realize they will be living in somewhat cramped quarters forever, will have limited food choices, they can never have kids, and they can't ever return to the Earth.

My agenda is keeping the colonists alive. Living in a low ceiling bunker with a dirt floor and no windows is decidedly less luxurious than a tuna can, but you won't develop brain damage from the radiation you'd receive living above ground. Did I mention that the bunkers will smell like sulfur and the water will smell like urine from the ammonia? That's not what I'd call luxury, but maybe your opinion differs. It'll be cheap, effective, and we can enclose as much space as we can collect sulfur to make concrete. That means more space for people and plants and faster growth.

Dook wrote:

Manufacturing on Mars is the only affordable way to do Mars colonization? Profit once again. We don't explore for profit. We're not going to colonize Mars for profit. Being able to manufacture tiny things like brackets with a 3D printer is not going to get you more oxygen, more water, or more food on Mars and those things are going to limit colonization, not habitat. Every new settler is going to land in a perfect habitat.

The colonists aren't exploring anything, they're establishing a branch of civilization on another planet. Eventually, it needs to sustain itself. The fewer resources that have to be thrown at the project, the fewer objections there will be from politicians.

I've no idea why, but you seem fixated on this bracket manufacturing thing. I want to use 3D printers to print bunkers. We've already done that here on Earth using what's available on Earth and we can do it on Mars using what's available on Mars.

Dook wrote:

Our government won't care about spending a couple billion dollars a year so NASA can do exploration and colonization with private companies? NASA gets about $17 billion a year every year. I think NASA should deploy three more Hubble telescopes so we would have a space interferometer and be able to see farther and with more detail. After that, I think all of NASA's budget should go to a Mars sample return mission, then three Mars Direct exploration missions, then Mars Direct style settlement.

That $17B is spread out through programs that study everything from how paint dries to rocket engines. The manned space program receives about $5B directed at space flight hardware development and usage, I think. The James Webb space telescope will allow us to see further into the universe than we've ever been able to, so NASA is already doing that. Now NASA has a mandate from President Trump to send humans to Mars and a signed budget that allocates funding for that purpose.

Dook wrote:

How would I recycle water better than NASA? My system wouldn't cost $1m or whatever it costs, and it would not break daily. It would have a DC water pump for the shower and filters. For the urinal, you would piss into a plastic can, use a hand pump to pump the urine through a particulate filter in a stainless steel can, once the can is full someone would take it to the greenhouse and use solar cookers/reflectors to boil out the water. Then use a little water and a hand scrub pad to get the salt off the can. No electronic monitoring equipment needed.

Did you submit your proposal to NASA? Sometimes they explore new ways of doing things and sometimes they don't. You won't know until your proposal is submitted, but they're going to want a working prototype.

The electric monitoring equipment determines the quantity of dissolved solids and trace contaminants to determine how pure the water is. Try your method and see what happens.

Dook wrote:

How many plants are we talking about for a greenhouse on Mars? Don't know. I can't even ballpark it at this point until I know how big of a greenhouse I can take. The greenhouse needs to be as big as possible, it's more important than having a hundred homes on Mars. Even so, without a doubt hydroponics would be the most successful but it can only grow certain plants. And, having a fish tank and algae tank would provide protein and 4 chickens would provide eggs.

How many people per colony or colony expansion increment? Give us that number, let's calculate the caloric and nutrient value of the various things you want to grow, and then we have some idea of how much we need of each plant or animal to provide enough calories or the calorie offset the produce and animals can provide if we're still shipping food from Earth.

Dook wrote:

There has to be some eventual payoff for colonization? No, there doesn't. People on the Earth would be ecstatic and want to check daily on how the colonists were doing. I would bet that NASA's budget would actually grow if they colonized Mars.

All human settlements up to this point in human history were eventually required to sustain themselves. Maybe people will feel differently about Mars. We should probably poll people to find out.

Dook wrote:

Mr. Musk has only figured out how to get a million people to Mars? No, he hasn't. He's proposed a fantasy that some of you have bought into.

He has? How do you know this?

Dook wrote:

How much do my trees weigh? When I bought them they weighed about 25 lbs, I guess, and they had a clump of dirt on the roots. Yes, trees retain water as they grow.

I need to know how heavy the trees are to determine what percentage of the weight is water.

Dook wrote:

How much do my trees weigh now? Don't know, if I had to guess I'd say they were maybe four times heavier than when I bought them, but not all of that is water. For vegetables any water retained by the non-edible parts of the plant stays in the greenhouse as compost. Edible vegetables that retain water transfer the water to people.

Would you ship the trees as saplings or when they're capable of bearing fruit?

Dook wrote:

Wouldn't it be a lot less expensive to obtain water from local deposits? Yes, but it has to be reasonable. It's not reasonable to drive far from the base, place a microwave, build a tent, power the microwave (using what power source?), then use some small pump to get some water vapor into some kind of container. All of that will get you a few drops. And, if your rover breaks down, you're dead.

I would collect the water before the colony is occupied by humans, so nobody is going to die. I also want to situate colonies near those buried glaciers that are tens of meters deep. The robotic tankers will collect the glacier water, return to the colony site, and then pump the water into storage tanks. The colony will still use water recycling, when it works properly. The heat source will be a small reactor or RTG, either of which produces plenty of waste heat. It'll use super capacitors for motive power.

Dook wrote:

Or, you can drive far from the base and use some drilling equipment to get dirty ice that you put into buckets and bring them inside your pressurized rover to warm it up. The ice melts, the dirt settles and you have maybe a few cups of water. Can you get some water this way? Yes. Not enough to really do anything with and if your rover breaks down far from base you lose people and you lose your rover.

We haven't lost Curiosity after multiple years of operation and it's an electric motor powered robot, just like the water tanker robots I proposed using. Since it's lasted for years on Mars without repairs of any kind, so will a water tank on wheels.

Dook wrote:

If we had large zeolite panels, placed them out on Mars for a month, brought them inside the greenhouse and used the solar cookers to heat them they will outgas CO2 and water vapor. It's not a lot but we shouldn't be losing a lot either, unless we're wasting our water to make rocket fuel.

Nobody here is proposing making rocket fuel on Mars using water shipped to Mars from Earth.

Dook wrote:

The greenhouse itself, once finished and warms up, will outgas some water vapor from the Mars regolith, so, just by doing that you get a water gain, it would not be a lot but it would be some.

How are you going to pressurize the greenhouse?

Dook wrote:

Two guys can't fill sand bags in three hours? Not two guys, four guys, two on top and two on the ground. They could pre-move a large pile of sand near the habitat. Also, I don't see the need for putting the material into sand bags, they can just pour it out on top of the habitat and then, when they are done, cover it with either a tarp or some kind of thin cloth and hold it down with rocks.

Pre-move a large pile of sand with what?

Dook wrote:

The task would require peak physical fitness? They don't need to be in peak physical fitness. The people that go will be fit or they don't get selected to go, can't have lazy people on Mars. If it's too much work then they will work a few hours each day on it.

The colonists don't need to be fit to fill sand bags, but they need to be fit or they're not going?

Do you recognize that there's a difference between shoveling dirt in a T-shirt and a pair of blue jeans and shoveling dirt in a space suit?

Wear full firefighting equipment (boots, suit, helmet, gloves, SCBA) on a cold day to prevent heat exhaustion, then try filling some sandbags. Let me know how that goes.

Dook wrote:

They need radiation shielding? They do. How long is it going to take your crew to get together all the sulfur and use a screen to sift the aggregate material to the correct size and then assemble all the aluminum screen to spray the sulfacrete onto, and then install all the monitoring equipment, connect the Moxie line to it, run the power line, and set up the water system? The top of my tuna can is covered in regolith in three or four days.

It won't take the crew any time to get the sulfur or the right aggregate size. They won't be going to Mars until the water and building materials are ready for use. Those are tasks to complete before the colonists show up.

Dook wrote:

Also, does the Red Dragon have water shielding?

Red Dragon only has a heat shield. It was never designed for human habitation.

Dook wrote:

We need 1.5 meters of shielding? Did you add in the water shielding that is already in place on the tuna can? I don't see us being able to move enough material to get 1.5 meters on top of the tuna can, maybe two feet of regolith might be it.

The entire tuna can has to be shielded with regolith because it's a thin aluminum can that makes the radiation problem worse unless it's made from something that doesn't irradiate its occupants with substantial secondary particle showers. To provide adequate shielding in deep space, the tuna can will never have a water tank mounted on the top of it. The water tank will always be mounted in the interior of the vehicle, the same as Dr. Zubrin's habitat layout illustrates.

Your sandbag idea would work if you had enough sandbags and were willing to devote enough time and/or earth moving machines to make the process faster, or better space suits if you insist on only using humans and shovels to fill sand bags. For long term survival, getting enough material between the colonists and what will eventually kill them is what matters and a foot of material won't cut it. It could be done over the course of a week with round-the-clock shifts, but it'll never be done in a matter of hours.

Dook wrote:

We need multiple meters of shielding to make it safe for pregnant women and children? There aren't going to be any pregnant women or children at the first settlements. The men will have to get vasectomies.

I'm accepting of human nature, but you want to mutilate otherwise healthy men to ensure there are no children. There are a few women who never want to have children, but most do. If you tell the women they can never have children, you've eliminated roughly 50% of the people who might be willing to go. This isn't an ant farm in a zoo for children to gawk at, these are real people who are trying to establish a second branch of human civilization. There will be children, like it or not. Since we have the technology to protect them, we should use it.

Dook wrote:

These problems affect your plans much more than they affect mine. You want the first settlers to have big luxurious homes on Mars and families and manufacturing and somehow return a profit to Elon Musk. It's just not going to happen that way at first because we don't have cryosleep or warp drive.

I want to build structures on Mars (housing and greenhouses) using Martian materials so they won't have to be brought from Earth, at a cost of hundreds of millions of dollars. An earthen house like those in Africa and the Middle East is hardly the lap of luxury, but people have lived in them for thousands of years.

Dook wrote:

A heated well pipe could extract water from frozen regolith? Hmm. Now that idea has some potential. Your settlement would have to be placed in an area with thick ice. You could do it right at your base. You wouldn't have to go that deep, maybe 100 feet down, so use ten 10' long drilling pipes. The water would not come up out of the well. The drilled hole would fill with Mars atmosphere at first, raising the pressure slightly, helping ice turn to water instead of vapor. You could dig the wall, then build your greenhouse over the well, then heat the well to make water.

Water Storage Sphere:

A Titanium sphere with a hole in it to insert a recessed stopper containing a radioisotope for heating to prevent freezing and a series of permanent magnets to seal the sphere for travel or to permit the other end of the drill pipe from the drill robot to be inserted to condense water in the sphere from the well drilled by the drill robot. The sphere will also contain two tracks of alternating pole permanent magnets affixed to the inside of the sphere so the drill robot can impart motive force by spinning a second set of alternating pole permanent magnets affixed to an electric motor mounted to the water drill robot. Maximum traveling speed will be about 2.5km/h when full.

Water Drill Robot:

An electric motor driven, radioisotope and super capacitor powered device that uses permanent magnets and rollers to balance atop the water storage sphere and to provide motive power and steering using magnetic gearing. The magnets mounted on the drill robot spin in close proximity to the magnets mounted inside the water storage sphere to produce torque. This power transfer principle is found in electric or hybrid cars that do not have physically geared transmissions. The rollers on the drill robot are the only parts that contact the sphere. Brushes will clean off the excess iron rich regolith that adheres to the sphere, but a thin layer of magnetized regolith provides traction for the otherwise smooth water storage sphere.

The motors and super capacitors won't be the kind found in cheap cordless drills, but the kind that we stick down extremely hot, corrosive, high pressure natural gas and oil wells to drill with here on Earth. The super capacitors require very little in the way of heating to function properly and even though the energy storage is poor, the idea is that the RTG on the drill robot charges the capacitors, it moves for a matter of minutes, stops to recharge, and then continues on. The magnetic drill pipe acts as a parking brake.

When the drill robot reaches the drill site, it detaches one set of rollers from the sphere by retracting the permanent magnet on one set of its four articulating roller arms, uses the sphere as a counterweight to raise the drill pipe to the vertical position, drills the well using a radioisotope heated drill head, the hot drill head melts the water in the bore hole, the water turns to steam when it contacts the hot drill head, the steam pressurizes the bore hole, it rises through the pipe into the cold Titanium tank, condenses back into water, and this process fills the sphere to capacity. The drill pipe is retracted from the well, the drill robot reattaches its other set of roller arms to the water storage sphere, and then it heads back to the colony with its water.

There are no pumps, the motors are completely sealed, and the sphere has a built-in radioisotope heating element to prevent the water from freezing in the sphere in transit. It may sound complicated, but the drill robot has three electric motors (two for motive power, one to turn the drill pipe) and four servos (one in each roller arm) to connect/disconnect from the sphere.

Dook wrote:

You would then need a Grundfos AC/DC submergeable well pump and 80 feet of 1" poly pipe (you don't want the well pump near the bottom because it will pick up dirt). The pump needs 4 amps, 30-300 volts DC, so you would have to have a certain section of thin solar array just for this purpose. The pump will put out about 3-5 gpm depending on which pump you use.

No pumps are required or desirable. The radioisotope thermal heaters, radioisotope thermal electric generator, and super capacitors are sufficient. Slow and low power are the key to making a water collection robot work reliably.

Dook wrote:

You would have to be careful not to get the well too hot or you would melt the poly pipe. I wonder if just using a fan to blow warm greenhouse air down into the well would be enough?

My drilling solution is all-metal for better durability.

Dook wrote:

You would only get so much water before it would run dry because you're only going to be able to heat the ground out to about a few feet. I don't know, maybe you could get a couple hundred gallons. That would work, I'm just not sure it's really worth it.

If the robot only weighs a metric ton or thereabouts, then every successful trip to the glacier after the first trip is money in our pockets to send more colonists and machinery.

Dook wrote:

Another option would be to not use a well pump at all and instead use zeolite cylinders. Super heat your well, drop the zeolite cylinder into the well on cables, pull them up and use solar reflectors to steam out the water inside your greenhouse. That would take longer but you could really use a lot more heat in the well and get more water in the long run.

If you superheated your well and your greenhouse was sitting atop the well head, then you shouldn't have to stick anything down the well unless the well was pretty deep and all the steam condensed to water before it came out of the well head. In any event, that'd be a great way to humidify a greenhouse.

Dook wrote:

All of this would have to be done near your base to use the heat available from the nuclear reactor so it would get you some water, not sure exactly how much.

Heat from radioisotopes like Plutonium is sufficient for this to work. A nuclear reactor produces a lot more heat and would get the job done faster, but at increased cost, complexity, and weight. Either way, the process requires a lot of heat.

Last edited by kbd512 (2017-04-16 18:15:28)

Dook · 2017-04-16 23:25:20

Trying to build Mars dirt homes is not maximizing available resources, it's all wasted time and effort and the components for those homes would mean more things would have to be launched from the Earth, not less. A rocket ship full of cryosleep people is never going to land on Mars. Every new settler sent will travel in a perfect Mars tuna can type habitat so habitat is not a limit to colonization whereas oxygen, food, and water are.

We can either ship people or life support functions and develop local resources? But we can't develop local resources. It's a non-successful effort from the beginning. It's not something that we just need to work hard at, you can't get enough from it to justify it. It's never going to give you more food, it's never going to give you more electricity, and the tiny drops of water that you will get won't justify the risk to peoples lives by having them travel far away from the base.

Your agenda is radiation shielding? Compare your one foot thick sulfacrete roof to the tuna can's 1 foot of water and one foot of regolith on top, which is better?

Your sulfacrete home means more space for people and plants? But they're not going to grow plants in the tuna can so if someone leaves it that doesn't really open up space for plants. It does mean more space for people but it's way too much outside work and way too much non-essential supplies sent from the Earth just to have one empty room in the tuna can.

Eventually a Mars colony needs to sustain itself? Correct. The limits to population are not shelter, since every settler lands in a perfect shelter. The limits are oxygen, food, and water. Oxygen comes from the Moxies. The colonists can't make a Moxie so that is out of their control. The colonists should be able to grow their own food and raise chickens and fish in a greenhouse. They should be able to learn and improve the process. Water is almost all recycled and maybe whatever they lose they can regain by using zeolite panels outside.

This idea that congress would cut the funding for a Mars colony and leave them to die is ridiculous. It would NOT happen. NASA ran the Apollo Program for years, and the Space Shuttle program as well. If the launch schedule gets too expensive you stop sending more colonists and you send necessary supplies only, once a year should be plenty.

Did I submit my proposal to NASA? I don't know anything that they don't. I just don't like over designing things unless it's necessary.

The waste water monitoring equipment determines the quantity of dissolved solids to see how pure the water is? This is exactly my point, you don't have to determine the quality of filtered urine but, of course, a NASA designer had to know how well it was working so he put a monitor on it. If you're dying of thirst, you can drink your own urine to survive. Other than that, you only have to filter it and boil it to release the water, scrub the salt out of your pan and discard, well, maybe save some of it since salt is necessary to the human diet.

How many people in my colony? Launch 1, Moxie into orbit. Launch 2 is an RTG into orbit, they both dock together and blast off to Mars as one. Launch 3 is a second Moxie. Launch 4 is a second RTG, they dock in orbit and blast off to Mars. Launch 4 is a greenhouse. Launch 5 is food and water. They dock in orbit and go to Mars. Launch 6 is a rover hanger. Launch 7 is a tuna can with 4 crew. They dock and go to Mars.

The greenhouse size? I don't know, what's the largest number of hard plastic panels I can fit in a tuna can sized container?

All further settlements arriving would be the same as above until we have at least three Moxies, three RTG's, three greenhouses, enough backup parts, AND the oxygen supplies are completely full and food stocks are full, only then would we send just people.

All human settlement up to this point in human history were eventually required to sustain themselves? That's what I'm doing, putting time and effort into food production is sustaining the colony. Maintaining the Moxie is sustaining the colony. Wasting time gathering and sifting dirt is not sustaining because they already have habitat.

Where is the BFR? I've seen drawings, that's all. He thinks that it's important for it to have a movie theater inside.
You need to know the weight of the semi-dwarf fruit trees to figure out what their water weight is? I'm not digging up my trees so you can find out.

Would I ship the trees as saplings or when they are capable of bearing fruit? Actually, I'm thinking the fruit trees are not a good idea. They have to have long warm summers to grow their leaves back and fruit and long cold winters to drop their leaves and go dormant. If it gets cold when they are growing new leaves or fruit they will drop the fruit and all their leaves. If it gets too warm when they are dormant they will wake up and start their leaves. And, they only produce fruit once a year.

I think the greenhouse used for hydroponics, other vegetables, and grains would be better and if something happens, the temperature drops somehow, you just lose some vegetables and not an entire years worth of fruit.

You would have a robot tanker collect glacier water? There is no glacier water on Mars. It's all frozen except for a very short time, between 33 and 36 degrees F in the day time. How much water is your robot going to collect in those few seconds? Is it going to use towels?

We haven't lost Curiosity? No, but Spirit had a stuck wheel for a while before it finally got too deep in the sand.

How am I going to pressurize the greenhouse? With a fan mounted on the airlock and with zeolite panels placed in the Mars atmosphere for weeks and brought inside and heated with solar reflectors to outgas water and CO2. Just before we start the plants a small oxygen bottle would be opened to give it some oxygen for the plants to use.
Pre-move sand with what? The two ATV's that come in the rover hanger would have blades on the front for moving sand.

The colonists don't need to be in "PEAK" fitness to move sand.

Do I recognize the difference between shoveling dirt in a T-shirt and doing it in a space suit? No shovels needed. You move the sand with the ATV's first, take a bucket and force it into the sand, turn the bucket upright, hook the rope (the rope end would have a metal hook on it) onto the bucket and let it go up. Up top they just toss the sand and send the bucket back down. Oh, and once they are done, they will cover the regolith with a thin circular solar array that has tabs that fit onto hooks in the side of the tuna can.

I should wear full firefighting equipment on a cold day and try filling some sandbags? No sandbags needed.

It won't take any time to get sulfur or aggregate if we wait and have robots do it all for us? I'm okay with that. That would mean we wait another 30 years or more but I'm okay with playing it safe. I'm not in a hurry to risk other people's lives on it.

The entire tuna can has to be shielded with regolith? No, it doesn't. Zubrin's idea was just the central airlock area would be shielded, but NASA's Deep Space Habitat has a water sack shielding all the way around so the tuna can would have that as well. And I know it's not a separate tank on top, it's a built in tank all around the habitat.

My sandbag idea would work if they had earth moving machines? They will have two ATV's with blades. No shovels needed, just dive the bucket into the sand pile. No sandbags needed either.

A foot of material on the roof won't cut it? You forgot about the foot of water in the water sack in the tuna can.

I want to mutilate otherwise healthy men? Hehe. The absolute best thing would be for people to quit as soon as they learn about how things will really be. The worst thing would be for them to make it to Mars then realize "Uh oh, this is a lot of hard work".

There will be children? NASA would have to promise people a way to come home, maybe after 10 or 15 years on Mars. I wouldn't bring them back. I would say "you go, you stay". That way you have to do good work because your survival is dependent on it. You get someone who is a month from going home and suddenly they don't want to work hard anymore.

How warm is this radioisotope drill bit? I doubt it will melt the ice as it goes through but you don't need to melt ice to drill through it, we have drills that go through solid granite, ice is nothing. You need to really heat the ice in order to change it to a warm vapor so it will float up on it's own into your storage tank. I don't think your drill bit will be hot enough. I don't think you're going to get very much vapor at all from this.

How much electricity is this drill going to use? How long is the drill, 10 feet?

Normal well drill pipes are hollow, like your idea, but they blow air down through the center of the pipe that cools the bit as the air goes outward around the drill bit and the air carries the powdered rock dust up and out of the well.

This robot will go to the glacier? That glacier might just be frozen CO2.

RobertDyck · 2017-04-17 03:29:50

Dook wrote:

Every new settler sent will travel in a perfect Mars tuna can type habitat

Not necessarily. I haven't posted my mission plan to "Alpha" yet. But my mission plan includes reusable interplanetary vehicle, that transits from Earth orbit to Mars orbit and back. The lander will be smaller than a Mars Direct hab. But rather than obsess over my plan, here is the one by Elon Musk and his team. He wants a reusable vehicle that goes from the surface of Earth to surface of Mars, and back. His vehicle is far larger than mine, but the point is settlers don't arrive in a tuna can.

kbd512 · 2017-04-17 05:48:56

Dook wrote:

Trying to build Mars dirt homes is not maximizing available resources, it's all wasted time and effort and the components for those homes would mean more things would have to be launched from the Earth, not less. A rocket ship full of cryosleep people is never going to land on Mars. Every new settler sent will travel in a perfect Mars tuna can type habitat so habitat is not a limit to colonization whereas oxygen, food, and water are.

NASA thinks otherwise and so do most other people interested in Mars colonization.

Dook wrote:

We can either ship people or life support functions and develop local resources? But we can't develop local resources. It's a non-successful effort from the beginning. It's not something that we just need to work hard at, you can't get enough from it to justify it. It's never going to give you more food, it's never going to give you more electricity, and the tiny drops of water that you will get won't justify the risk to peoples lives by having them travel far away from the base.

If that were true, NASA wouldn't be sending MOXIE to Mars. MOXIE is ISRU for oxygen.

NASA's Mars Reconnaissance Orbiter has already located glaciers containing tens of meters of solid ice and some are substantially deeper than that. The glaciers contain approximately 150 billion cubic meters or 36 cubic miles of ice.

Dook wrote:

Your agenda is radiation shielding? Compare your one foot thick sulfacrete roof to the tuna can's 1 foot of water and one foot of regolith on top, which is better?

My agenda is preventing brain damage. I'd rather the colonists kept working on the Mars colony. Brain damage might make that rather difficult. It might be really difficult to get another group of volunteers if the first can't remember their names after a couple years. Can you understand that or am I wasting my time trying to explain the concept?

You said one foot, I said one meter. 1 meter is 3 feet and 3.37 inches. 1 meter is more shielding than 1 foot, at least to those of us who have figured out how to use the metric system.

Dook wrote:

Your sulfacrete home means more space for people and plants? But they're not going to grow plants in the tuna can so if someone leaves it that doesn't really open up space for plants. It does mean more space for people but it's way too much outside work and way too much non-essential supplies sent from the Earth just to have one empty room in the tuna can.

Yes, functionally unlimited building materials laying around everywhere on the surface of Mars means more structures get built at a fraction of the cost of shipping them from Earth. If the robot builds one bunker successfully, then it paid for itself many times over because the size of the tuna can going to Mars can be tiny since all the colonists can live in the bunker.

Dook wrote:

Eventually a Mars colony needs to sustain itself? Correct. The limits to population are not shelter, since every settler lands in a perfect shelter. The limits are oxygen, food, and water. Oxygen comes from the Moxies. The colonists can't make a Moxie so that is out of their control. The colonists should be able to grow their own food and raise chickens and fish in a greenhouse. They should be able to learn and improve the process. Water is almost all recycled and maybe whatever they lose they can regain by using zeolite panels outside.

Since we're paying for everything we send, some positive measure of self-sufficiency would be most welcome.

Dook wrote:

This idea that congress would cut the funding for a Mars colony and leave them to die is ridiculous. It would NOT happen. NASA ran the Apollo Program for years, and the Space Shuttle program as well. If the launch schedule gets too expensive you stop sending more colonists and you send necessary supplies only, once a year should be plenty.

The Apollo program was cancelled, but the President didn't leave any astronauts on the moon. I never said anything about Congress leaving people to die. I attempted to convey, and apparently failed, that the politicians may decide to divert funding elsewhere if the program becomes inordinately expensive. That means the colony won't grow and Congress will probably insist on shipping everyone back to Earth, pissing away all that hard work. That's exactly what happened to the NERVA program.

Dook wrote:

Did I submit my proposal to NASA? I don't know anything that they don't. I just don't like over designing things unless it's necessary.

How do you determine what's necessary?

Personally, I don't like the idea of paying for water when I'm living on top of a giant ice cube.

Dook wrote:

The waste water monitoring equipment determines the quantity of dissolved solids to see how pure the water is? This is exactly my point, you don't have to determine the quality of filtered urine but, of course, a NASA designer had to know how well it was working so he put a monitor on it. If you're dying of thirst, you can drink your own urine to survive. Other than that, you only have to filter it and boil it to release the water, scrub the salt out of your pan and discard, well, maybe save some of it since salt is necessary to the human diet.

Yeah, because who cares if the water you drink slowly kills you. I guess the people who actually do this stuff for a living want to know if they actually did the job right before someone dies.

Dook wrote:

How many people in my colony? Launch 1, Moxie into orbit. Launch 2 is an RTG into orbit, they both dock together and blast off to Mars as one. Launch 3 is a second Moxie. Launch 4 is a second RTG, they dock in orbit and blast off to Mars. Launch 4 is a greenhouse. Launch 5 is food and water. They dock in orbit and go to Mars. Launch 6 is a rover hanger. Launch 7 is a tuna can with 4 crew. They dock and go to Mars.

MOXIE and RTG's are so small and light that you can deliver all of them with the tuna can. The food and water would require their own rocket.

Dook wrote:

The greenhouse size? I don't know, what's the largest number of hard plastic panels I can fit in a tuna can sized container?

That depends on what else is in the tuna can. What else do you want to put in the can?

Dook wrote:

All further settlements arriving would be the same as above until we have at least three Moxies, three RTG's, three greenhouses, enough backup parts, AND the oxygen supplies are completely full and food stocks are full, only then would we send just people.

What do you consider "completely full"?

Dook wrote:

All human settlement up to this point in human history were eventually required to sustain themselves? That's what I'm doing, putting time and effort into food production is sustaining the colony. Maintaining the Moxie is sustaining the colony. Wasting time gathering and sifting dirt is not sustaining because they already have habitat.

Yes, building structures on Mars is a waste of time because the rockets and habitats are so darn cheap. Congress will simply send more money to NASA if they ask for it.

Dook wrote:

Where is the BFR? I've seen drawings, that's all. He thinks that it's important for it to have a movie theater inside.
You need to know the weight of the semi-dwarf fruit trees to figure out what their water weight is? I'm not digging up my trees so you can find out.

Well, there's a picture of Mr. Musk and other SpaceX staff standing in front of the composite LOX tank test article, pictures of it at sea on a barge for pressure testing, and a video of the Raptor engine prototype firing on a test stand. I guess we could pretend that he's just throwing money around to do that as some sort of PR stunt, but I have a hunch that he wants to build the rocket or he wouldn't be paying people to fabricate and test hardware. If NASA had given him as much money as they've thrown at SLS, the damn thing would've been built by now.

Dook wrote:

Would I ship the trees as saplings or when they are capable of bearing fruit? Actually, I'm thinking the fruit trees are not a good idea. They have to have long warm summers to grow their leaves back and fruit and long cold winters to drop their leaves and go dormant. If it gets cold when they are growing new leaves or fruit they will drop the fruit and all their leaves. If it gets too warm when they are dormant they will wake up and start their leaves. And, they only produce fruit once a year.
I think the greenhouse used for hydroponics, other vegetables, and grains would be better and if something happens, the temperature drops somehow, you just lose some vegetables and not an entire years worth of fruit.

PB & J would be nice. Any chance of getting some peanuts and berries to grow in that greenhouse?

Dook wrote:

You would have a robot tanker collect glacier water? There is no glacier water on Mars. It's all frozen except for a very short time, between 33 and 36 degrees F in the day time. How much water is your robot going to collect in those few seconds? Is it going to use towels?

The water robot "unfreezes" it using heat from decaying Plutonium. The reason the Plutonium in those RTG's glows is that it's hot. The temperature of the Plutonium dioxide ceramic can reach 1050C or 1922F on the surface. Unless the water on Mars melts at the same temperature as copper, then I think the Plutonium dioxide pellet in the tungsten carbide drill head will get the job done.

Dook wrote:

We haven't lost Curiosity? No, but Spirit had a stuck wheel for a while before it finally got too deep in the sand.

The water robot will produce a lot more torque than the motors in Spirit.

Dook wrote:

How am I going to pressurize the greenhouse? With a fan mounted on the airlock and with zeolite panels placed in the Mars atmosphere for weeks and brought inside and heated with solar reflectors to outgas water and CO2. Just before we start the plants a small oxygen bottle would be opened to give it some oxygen for the plants to use.

Unless it's mounted to a jet engine, a simple fan won't pressurize anything. Compressors are required.

Pre-move sand with what? The two ATV's that come in the rover hanger would have blades on the front for moving sand.

The colonists don't need to be in "PEAK" fitness to move sand.

Dook wrote:

Do I recognize the difference between shoveling dirt in a T-shirt and doing it in a space suit? No shovels needed. You move the sand with the ATV's first, take a bucket and force it into the sand, turn the bucket upright, hook the rope (the rope end would have a metal hook on it) onto the bucket and let it go up. Up top they just toss the sand and send the bucket back down. Oh, and once they are done, they will cover the regolith with a thin circular solar array that has tabs that fit onto hooks in the side of the tuna can.

Once again, simply dumping sand on top of the habitat won't accomplish much. You need sand around the sides of the can, too, and the Zubrin tuna can is 33 feet tall when it lands on Mars.

Dook wrote:

I should wear full firefighting equipment on a cold day and try filling some sandbags? No sandbags needed.

If I was dead-set on above-ground habitats, I'd make sure the tuna can landed in a crater (because GCR's impacting the sides of the tuna can still do just as much damage as GCR's impacting the top of the tuna can) and then sand bag the top, assuming it could take the weight of a meter of regolith.

Dook wrote:

It won't take any time to get sulfur or aggregate if we wait and have robots do it all for us? I'm okay with that. That would mean we wait another 30 years or more but I'm okay with playing it safe. I'm not in a hurry to risk other people's lives on it.

Curiosity didn't take 30 years to design, build, and test. A cement truck for Mars won't take 30 years to design, build, and test, either.

Dook wrote:

The entire tuna can has to be shielded with regolith? No, it doesn't. Zubrin's idea was just the central airlock area would be shielded, but NASA's Deep Space Habitat has a water sack shielding all the way around so the tuna can would have that as well. And I know it's not a separate tank on top, it's a built in tank all around the habitat.

Yes, it does. Zubrin's water tank was a small PE cylinder located in the center of the habitat module that was designed to stop solar flares only. He ignored the GCR problem. His tuna can was also built for astronauts who were coming back to Earth in two years. We're sending people to Mars for the rest of their lives.

Dook wrote:

My sandbag idea would work if they had earth moving machines? They will have two ATV's with blades. No shovels needed, just dive the bucket into the sand pile. No sandbags needed either.

I was thinking of a simple bucket to fill sand bags, but ok, no sand bags.

Dook wrote:

A foot of material on the roof won't cut it? You forgot about the foot of water in the water sack in the tuna can.

A foot of water 33 feet in diameter is 6,398 gallons and it weighs 53,359 pounds. The total weight of Dr. Zubrin's tuna can was only 55,440 pounds when it landed on Mars.

Dook wrote:

I want to mutilate otherwise healthy men? Hehe. The absolute best thing would be for people to quit as soon as they learn about how things will really be. The worst thing would be for them to make it to Mars then realize "Uh oh, this is a lot of hard work".
There will be children? NASA would have to promise people a way to come home, maybe after 10 or 15 years on Mars. I wouldn't bring them back. I would say "you go, you stay". That way you have to do good work because your survival is dependent on it. You get someone who is a month from going home and suddenly they don't want to work hard anymore.

?

Dook wrote:

How warm is this radioisotope drill bit? I doubt it will melt the ice as it goes through but you don't need to melt ice to drill through it, we have drills that go through solid granite, ice is nothing. You need to really heat the ice in order to change it to a warm vapor so it will float up on it's own into your storage tank. I don't think your drill bit will be hot enough. I don't think you're going to get very much vapor at all from this.

The drill bit is warm enough to go through aluminum like butter.

Dook wrote:

How much electricity is this drill going to use? How long is the drill, 10 feet?

The pipe can be about 10 meters or 33 feet in length.

Dook wrote:

Normal well drill pipes are hollow, like your idea, but they blow air down through the center of the pipe that cools the bit as the air goes outward around the drill bit and the air carries the powdered rock dust up and out of the well.

The bit won't be turning very fast or for very long because the electric motor is powered by a super capacitor. The tungsten carbide head doesn't require coolant unless we're drilling through granite, in which case we may want to send the robot to a better site.

Dook wrote:

This robot will go to the glacier? That glacier might just be frozen CO2.

CO2 and H2O don't produce the same radar return. That's how they figured out that they were looking at ice.

louis · 2017-04-17 05:52:59

Musk's ITS is supposed to be able to deliver 450 tonnes of cargo to Mars... yes 450!

So say Musk is thinking big is a complete understatement!

He's talking about a thousands ITS craft heading to Mars every 2 years and using the cargo facility to begin with.

With just 10 trips he could land 4500 tonnes of cargo...effectively he will be able to export a complete industrial infrastructure for all essentials with those 10 trips.

It's an incredible vision. My main concerns are not over whether it is technically feasible but:

1. Whether the mission will be doable financially. He is assuming there are thousands and thousands of people (mini Musks perhaps) prepared to up roots, leave family and pay $200,000 per person for an uncertain future in a world that will not be the sort of natural environment they are used to...

2. Who are going to be the 100,000 colonists? Will they have the necessary skills, tenacity and personal attributes to make good colonists? How are they going be governed, or how will they govern themselves?

3. Because it is such a vast and ambitious project I think at some point it is going to attract political attention, and not necessarily in a good way.

These concerns lead me to favour a slower build up, with the first few decades' worth of colonists comprising essentially professionals: scientists, technicians, and trained explorers. Maybe artists and other creative people as well. But not people who are looking to settle for life. For one thing we need to have a full assessment of the effects of .38 G on the human body and also on reproductive processes.

However, if Musk can pull it off, I won't be criticising him for sure!

louis · 2017-04-17 06:47:20

Dook has become our resident Eeyore, which I think is nice. It's good to have a wall of negativity to bounce ideas off and to challenge any unwarranted optimism.

As indicated above, if Musk's plans mature then that is a complete game changer. You hardly need to make anything to begin with if you can send 10,000 tonnes of cargo every couple of years. Or rather, you can take the factory with you and assemble it on Mars.

However, more modest approaches do in my view require innovative ISRU. I believe it is possible. I haven't yet come across an industrial process that can't be replicated on a small scale. Mars has some special challenges that aren't found so much on Earth but I think it's good also to remind ourselves just how benign the environment is in many ways: no earthquakes, hurricanes, devastating tornadoes, huge floods, tsunamis or deluges of rain. Light winds and dust storms are about the worst of it. Temperature is a problem, but we've shown we can live comfortably in Antarctica all the year round. We've shown we can live in orbit for long periods (ISS). We've already landed humans on another celestial body.

The idea we can't easily locate water and generate oxygen I just don't accept. We have significant water signals for huge swathes of the planet. Electrolysis is a simple process. We collect the permafrost regolith and we melt out the water ice which is then put through a filter process. For producing hydrogen and oxygen, we put the water in large basin we construct on Mars (e.g. from formed basalt) and we do the electrolysis with equipment brought with us from Earth. We're supposed to get 8 kgs of oxygen and one of hydrogen for 50 KwHs. Compression will require more energy - but not huge amounts.

Oldfart1939 · 2017-04-17 08:21:31

Louis-

I agree that water, once located, will not be as problematic as Eeyore has surmised. In another post on another thread, I suggested doing something similar to strip mining coal and hauling the still frozen blocks to a processing facility. This could be a giant plastic lined excavated "swimming pool," in a heated dome. It could have several Radioisotope decay heaters arranged to melt the "harvested product," but will require further processing to become usable for potable water. It could be used directly for electrolysis to H2 and O2.Eeyore has suggested that my proposed centrifuge isn't necessary, but it's way more effective than filtration. Filters clog and need cleaning or replacement; a basket centrifuge is simply cleaned using the built in "plow." Chances are, the water will be either alkaline or briney, requiring further treatment for agricultural and drinking. It could be used directly for some sanitation purposes, but mostly for subsequent electrolysis. I recall GW mentioning that blocks of Iron ore in the Mesabi range being about a "cubit" in size. Blocks of soil contaminated ice shouldn't begin to melt or sublime away during transport to the processing dome. All this drilling and melting to get the water sounds unnecessarily complex to me.

Last edited by Oldfart1939 (2017-04-17 08:22:34)

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