Let's Design a Settlement for Mars!

arobie · May 1, 2005

Right now, I'm working out our Interplanetary Spaceship. I'm finding a rough estimate of it's mass so that we can then calculate about how much propellant we will need for a trip to Mars which we can then refine as our designs become more exact. We are going to plan for two scenarios, one where we are allowed a Nuclear Power Generator, and one where we have to use Solar Panels to create fuel cell fuel to make electricity. So...what we need to find out: How big would our Nuclear Power Generator be? How much power will we need for the trip? With that amount of power needed, how many square meters of Solar Panels will we need? And... How big would the fuel cells be? Now Dan_Casale, I have a question for you, dealing with the crew's breathable atmosphere. You provided the number for the oxygen needed per person per day. I assume that oxygen is not meant to be the only gas in the air. What percent of all the gasses is the oxygen supposed to make up? What other gasses will we have in the air? According to Earth's atmospheric makeup, nitrogen. Do we want to add any other gas for any reason?

arobie · May 1, 2005

At the bottom of this post is an insight into how I imagine the Interplanetary Spaceship, a rough sketch, a visual if you will. It is not accuate in relative sizes. I imagine the Booster will have to be much larger to get the hub, trusses, habitats, storage, and orbit to surface vehicle to Mars. It's current size in relation to the rest is surely too small. The storage will also have to be larger than it is. The trusses might also have to be longer than they are. I'm not sure what length is good for spin-gee. Speaking of spin-gee, Spacester, somewhere you said you had studied the dV requirements for spin gee. I can't remember where or when, but what did you find? What range of dV are we looking at to spin up the ship? As to why I drew this up, I did so to give my brother a visual since he was wondering what I was discussing on here all this time. I thought I would post it for you all too just because. It doesn't really contribute much, but hey enjoy it. Also, I'm not sure if you will be able to read what I wrote on it. My handwritting is a bit messy, and I had to minimize the file to make it fit on here. This did get me thinking more about design. Dan, I was thinking about how much food, water and oxygen we want to take along on a manned trip. You plan to take enough consumables for 960 days. I went though and added all the masses that we know so far, the mass of the people, the oxygen, personal items, food, and water. Taking enough for 960 days, it adds up to 452.9 tonnes. (I used a 10% efficiency with minimum usesage to find the water mass, just like I did a few posts up.) To get that mass to Mars it takes 737 tonnes of propellant (CH4/O2). Taking what we need of the same things as above for a 200 day trip, it adds up to a mass of 118 tonnes. To get this mass to Mars, it takes 192 tonnes of propellant. I didn't even include the mass of the tanks, engines, or any of the 'hardware' of the ship in figuring these mas

arobie · May 1, 2005

Sorry, I screwed up for this post.

arobie · May 1, 2005

The Drawing:

dan_casale · May 2, 2005

Arobie, The drawing is a very good start. Thanks. />>...You provided the number for the oxygen needed per person per day. I assume that oxygen is not meant to be the only gas in the air. What percent of all the gasses is the oxygen supposed to make up? What other gasses will we have in the air? According to Earth's atmospheric makeup, nitrogen. Do we want to add any other gas for any reason?<< Very good question, however I don't have a good answer for you. *speculation* I suspect we want something like the major gases on Earth. (Nitrogen, Oxygen, and CO2) However, I don't know all the gases that plants require to grow. I wonder at what kind of atmosphere we could generate from Mars resources. At least in the greenhouse areas we should have this kind of an atmosphere to help get the plants adjusted to Mars normal. *end speculation* />>I went though and added all the masses that we know so far, the mass of the people, the oxygen, personal items, food, and water. Taking enough for 960 days, it adds up to 452.9 tonnes.<< I was using the 960 day figure for safety. I think we need to answer the question about what is the minimum return trip time for an aborted mission? *Ugly What If Tree* If we use the Zubrin Mars Direct model, and launch when we know that we have lifesupport and return fuel on Mars. While enroute the supplies on Mars has a catastrophic failure (splendid explosion). Do we then have enough on-board supplies to: 1) Stay on Mars and use the backup hab that flew with us? OR 2) Use the onboard supplies and return to Earth? *end Ugly What If Tree* Would it be possible to park supplies in Mars orbit that could be used for an emergency return trip? What if the problem was a Delta-V failure? I think Mental or Spacester has done some of these calculations about how long the total trip was, if we are throwing "rocks" at Mars. />>If we can

arobie · May 2, 2005

Very good question, however I don't have a good answer for you. *speculation* I suspect we want something like the major gases on Earth. (Nitrogen, Oxygen, and CO2) However, I don't know all the gases that plants require to grow. I wonder at what kind of atmosphere we could generate from Mars resources. At least in the greenhouse areas we should have this kind of an atmosphere to help get the plants adjusted to Mars normal. *end speculation* Well, the basic building blocks to life are Carbon, Oxygen, Nitrogen, and Hydrogen. As you know, humans breathe in oxygen, but get the rest of those elements from what we consume. Plants "breathe" in Carbon Dioxide and get the other elements from the soil. The only element humans need in the atmosphere in order to live is oxygen. The only compound plants need from the atmosphere is carbon dioxide, which they take with water and sunlight to make C6H1206 (glucose) and give off oxygen...a process which we know as photosynthesis. An interesting note is that plants are doing better right now on Earth because of the increase in the carbon dioxide in our atmosphere. With our plants in our settlement and ships, we might want to increase the carbon dioxide for them because of this. So because of plants needs, from Mars' atmosphere we could make a great atmosphere for them. Another interesting fact is that with nitrogen being 78% of our atmosphere, neither plants nor animals pull it out of the air. Nitrogen-fixing bacteria on plant roots make it useable by plants, and then we consume it from the plants or animals whom eat plants and so on. I say our man-made ship and habitat atmosphere should be what you said: N, O, CO2. Quantity in that order...although we might not want to have the same high proportion of nitrogen as we have on Earth since it is pretty much useless in the air. If we reduce the percent of nitrogen though,

arobie · May 2, 2005

Dan_Casale, To adress the mission safety issues brought up, Digging back way in the beginning of the thread when we were discussing the first few cycles of the settlement and what goes when...back on the first and second pages...We decided that we plan on getting ISRU up and running before the first manned cycles, and that we plan on having an orbital refuge in LMO. In the time for the first crew to arrive, we will have the ISRU repropping operations up and running at Mars. We also plan on having an Orbital Refuge in LMO. Those are, I would say, some of the main things that we need to have on our just now established Before We Send a Crew to Mars Checklist (BWSCMC). We also need to have atmosphere, food, and water for atleast, I would say, 960 days at Mars before we send a crew. We could have it all up in orbit for the crew to bring down to the surface when they arrive, or we could split it up between having some supplies surface bound and some at the orbital refuge. I'm not sure of the minimal return trip time for an aborted mission, but I would think that once you set out and go, you could not return until the next window...2.5 years from then. Not sure though... Also, one other thing. I didn't mean to bury my first May 1st post. Do you know about any of the questions I posed about our power generation methods an the relative masses of each?

scottb50 · May 2, 2005

Nitrogen offer a very good alternative to pure Oxygen, I think Apollo 1 made that pretty clear. As far as CO2 it is a matter of keeping the level down, that's why they use Lithium Hydroxide to absorb the CO2 on the Shuttle and ISS. The problem is you have to bring it into orbit and dispose of it after it is used. Nitrogen provides pressurization and Oxygen is added as needed for the crew. The other concern you haven't mentioned is water vapor, or humidity. People expel a lot of water just breathing, so you have to control that. To carry enough Lithium Hydroxide canisters to get to Mars and back, as well as exist there also presents a problem, so another solution has to be found, and plants don't offer the best solution, by themselves. What is needed is a means of removing water vapor from the atmosphere as well as Carbon Dioxide that is sustainable and cost effective. Water would be recycled and whether CO2 could be processed to release the Oxygen economically or simply dumped overboard would be the next question. Luckily it is a fairly simple problem, water freezes at 0C and CO2 at -78.5C, so either liquid Nitrogen or liquid Oxygen could be used to remove them. <div class="Discussion_UserSignature"> </div>

crossovermaniac · May 2, 2005

Reusable multipurpose shuttles have proven to be expensive and highly inefficient here on Earth. They also requires a great deal of maintenance and refitting. I suggest that the same would be true for Mars. If significant savings can be obtained from parachutes/parasails, unmanned cargo vessels should be able to make the trip from Earth to Mars orbit AND land the cargo on the surface. I thought the same thing. I was wondering if pressure-fed rockets could be used instead of the rockets with turbopumps. Pressure-fed rockets are much simplier and could be maintained if the colony had a machine shop.

arkady · May 3, 2005

Concerning the ISRU. Im sure this it not news to the majority of people here, but I remember reading about air miners in KS Robinsons Mars trilogy, and have been wondering about the merit of the idea. Is this along the lines you were thinking in respect to the initial gathering of resources for the settlement ? Not gonna try explain with my own words, might aswell go ahead and quote the damn thing. "The air miners were big metal cylinders, somewhat resembling 737 fuselages except that they had eight massive sets of landing gear, and rocket engines attached vertically to their sides, and two jet engines mounted above the fuselage fore and aft. Five of these miners had been dropped in the area some two years before. In the time since, their jet engines had been sucking in the thin air and ramming it through a sequence of separating mechanisms, to divide it into its component gases. The gases had been compressed and stored in big tanks, and were now available for use. So the Boeings each now held 5.000 liters of water ice, 3.000 liters of liquid oxygen, 3.000 liters of liquid nitrogen, 500 liters of argon, and 400 liters of carbon dioxide." KS Robinson - Red Mars Another quote from the cover in case there should be any thats not familiar with the books. <img src="/images/icons/wink.gif" /> "Staggering - Required reading for the colonists of the next century" - Arthur C. Clarke <div class="Discussion_UserSignature"> "The choice is the Universe, or nothing ... " - H.G Wells </div>

arobie · May 3, 2005

Thank you Scottb50, I had forgotten about water vapor. It's funny because yesterday in biology class when we were talking about the Carbon and Nitrogen cycles, I was thinking about about exactly what we are discussing now, Carbon and Nitrogen in our ship atmosphere. I had my head down on the cool metallic science tables. When I picked my head up, I particularly noticed the pool of water where I had been breathing and wiped it up. It didn't click in my mind though that it was another thing we would have to control in our atmosphere. Strange. Ok, so we can pass the air through 'cold filters' to filter out the water and CO2. I like it, simple enough. Now, I don't know if this will be a problem, but we will want to watch to make sure that not too much CO2 is filtered out of the atmosphere where the plants are. In fact, we could actually keep a slightly higher level of CO2 in there for the plants, they would grow better. Water would be recycled and whether CO2 could be processed to release the Oxygen economically or simply dumped overboard would be the next question. Yes CO2 could be processed economically. The most economical way we know of is photosynthesis by plants. Thay take it in(to be exact, they take in 6H2O and 6CO2), and produce Glucose (C6H12O6) and give off 6O2. They take in water and our waste gas, and produce food for them and us and oxygen for us. They seem to be the most economical and efficient method for this. I'm not sure of other methods to break up CO2. I figure that we will have to have a dual system. We will need mechanical means of filtering the CO2, but we will also utilize plants, since we are going to bring them as a food source, and they do an excellent job at exactly what we need. Now my question is: How much of the burden of scrubbing the CO2 out of the air would plants relieve? In a closed-loop system, how many plants

scottb50 · May 4, 2005

I wouldn't want to depend on plants and hydroponics without a backup method. Any transit vehicle design has to be mass efficient, we can't take the equivalent of the Biodome, which didn't work very well by the way. We also haven't done a lot of testing growing crops in Space, could we use solar energy for the plants without providing a harmful environment for humans, or the plants themselves, or would we need the mass and energy consumption of artificial lighting? If we grow wheat we have to grind it into flour, more equipment needed. Perhaps premade flour could be taken easier. Though it sounds like an elegant solution what happens if the crops die for some reason? It may be more economical to carry dehydrated or even frozen foods than the equipment to grow it, less altruistic but more rational. One thing to look at is the work load required. Do we spend all of our mission tending crops, or doing exploration and science? Look at ISS, most of the crews time is spent keeping the station operable, they have little time for other duties let alone growing their own food. <div class="Discussion_UserSignature"> </div>

arobie · May 4, 2005

Scottb50, I envision a dual system, using both biological and traditional or mechanical means of filtering our air and providing food. On the transit ship and orbital station(s), I can see plants supplementing our filters and our food supply, while at the settlement on Mars, I can see it the other way around. On transit or in orbit, at the very most, the plants could provide a portion of food and recycle much oxygen while doing so. I, like you, can't see a full blown biodome in transit, to much power (with artificial lighting) and mass requirements to haul around every trip. But there has to be a compromise where plants save us more mass than they take. For a 200 day trip there, we would have to take 9.798 tonnes of oxygen with us. Plants, recycling our CO2 and releasing back our oxygen, could greatly reduce that. We need to know how many of a species of plant recycles how much CO2 giving off how much O2 in how much time. Then we could figure out with how many plants can we save how much mass. They save mass because as I understand it, when we filter out CO2 by a mechanical means, we just pull it out of the air and store it or release it to space. Plants on the other hand break it up and recycle our oxygen for us, saving us mass because we won't have to replace all of the oxygen that we bind to carbon then throw away. At the settlement on the surface, plants would then become well worth the while. Their recycling efficiency and food production are more than enough incentive at a permanent settlement. It would have to be supplemented by a mechanical means and food supply to serve as backup just in case something did happen. Wheat was just an example and the plant used in experiments to test the viability of a closed plant-human system. Just about any plant could be grown, many easily fixed up to serve as food. Pluck a tomatoe. Pull up a potatoe. Pluck strawberries, or carrots, or peanuts, rice, lettuce, or

north_star_rising · May 4, 2005

Arobie, Good outline!

See this project, which you may want to use in your planning! ;-) Here is the link to where the picture below can be found. International Solar Cruiser Program Weblink: http://www.international-space-agency.net/iscp.html Also, you can see the OSIRIS Manned Mars Spacecraft here, good reference also. http://www.abo.fi/~mlindroo/Station/ss1984_3.htm

ldyaidan · May 5, 2005

I would think that plants producing fruit or veggies, would be a better choice than wheat. It does take a lot of room to grow enough wheat to make flour, as well as a lot of work to grind it down. Plants that give fruit or veggies would a) give more variety to suppliment packaged food, and b) have a more positive psychological effect, simply adding color to the environment. Long space journeys are going to be very taxing, as the explorers will be trapped in limited space for an extended period. Having a "taste of home" as it were will help this journey. I do, however, think that taking seeds for crops like wheat is an excellent idea, to use when they arrive.

arobie · May 6, 2005

north_star_rising, Thanks. <img src="/images/icons/smile.gif" /> ldyaidan, I completely agree on everything. <img src="/images/icons/cool.gif" /> To all, Any disagreements, comments, or anything to add to anything I've said about using plant-human systems? How do you envision it? How much should we...or could we use plants en transit on the interplanetary ship?

scottb50 · May 7, 2005

On a Mars trip I doubt there would be much time, if we consider each trip as a one off project. I know of few fruits that mature in two months. If we use a cycling transport, leaving LEO for LMO and returning it would be possible to have an ongoing program, as it would at a surface facility on Mars, but as part of a one shot mission it wouldn't make a lot of sense to me. <div class="Discussion_UserSignature"> </div>

grooble · May 7, 2005

Talking of plants, has anyone considered genetically modified ones?

spacester · May 8, 2005

OK here’s my thinking on plants. A robust Settlement is successful at Agriculture and Aquaculture. Success implies a high level of recycling. Recycling implies that you have an ecosystem in balance. So we need to establish an ecosystem, in fact we need it to have multiple nutrient paths to prevent overall failure due to isolated species failures. Working towards a robust Settlement “someday” implies (IMO) that we should get started right away on food production. Also, I want a small bio facility as soon as possible to keep the life science folks equally involved in the PSA / Schools partnership. Settlement is about lots of different societal functions, we’re very inclusive, so we need to build life science equipment sooner than later. On energy: Let’s put that 5 MW Nuclear generator from Boeing down on the surface right away. How much does that thing mass? Maybe that’s our HLLV payload size calculation right there. Let’s also have fuel cells. Let’s make water LH2 and LOX with the excess electricity in the early days and store up a bunch of emergency energy. The fuel cells could be run just enough for proper maintenance in the early days (pre-settlers) then cranked up later as required, possibly for artificial lighting for flora and fauna production. Maybe the fuel cells are distributed amongst the various hardware that lands on Mars – everything has on-board power via emergency fuel cells, and you network them to provide highly reliable backup power. Maybe a sandstorm shuts down the nuke for some reason – you survive on stores and emergency generators. So I’m thinking the early ISPP (CH4 / O2) equipment also has fuel cells, even if relatively small. We need fuel cell technology to be space-reliable for our Mars Moon Asteroids vision to bear fruit, so we develop that technology on the earliest program schedule. So back to plants. Salad greens galore. Your carbs (starches) come from surface stores and your protein <div class="Discussion_UserSignature"> </div>

grooble · May 8, 2005

GM Fish: http://news.bbc.co.uk/2/hi/science/nature/3565041.stm More meat in less time.

cosmictraveler · May 10, 2005

Why not just genetically modify humans to be able to adapt to any type of environment that exploration craft find? That way there's no need for any fancy types of living quarters for we can just live off the land. <div class="Discussion_UserSignature"> It does not require many words to speak the truth. Chief Joseph </div>

spacester · May 10, 2005

Why not just genetically modify humans Well, if that ain't FutureTech, nothing is. <img src="/images/icons/laugh.gif" /> One of the first rules is: No FutureTech allowed in the Settlement plan. <div class="Discussion_UserSignature"> </div>

scottb50 · May 10, 2005

Let’s also have fuel cells. Let’s make water LH2 and LOX with the excess electricity in the early days and store up a bunch of emergency energy. The fuel cells could be run just enough for proper maintenance in the early days (pre-settlers) then cranked up later as required, possibly for artificial lighting for flora and fauna production. Maybe the fuel cells are distributed amongst the various hardware that lands on Mars – everything has on-board power via emergency fuel cells, and you network them to provide highly reliable backup power. Maybe a sandstorm shuts down the nuke for some reason – you survive on stores and emergency generators..... Just what I have been saying, except why bother with a reactor? Multiple, small, fuel cells and hydrolizers would provide more than enough backup. I don't think it would be feasible to take multiple reactors, so you have to have adequate backup no matter what. Why not just eliminate the reactor completely? It also follows that if we intend to use H2, O2 fuel cells we can use H2 and O2 just as well for propullsion, it's just a matter of how much you produce and store. This would eliminate the equipment needed to produce CH4 as well as the need to transport a large amount of LH2 to make it and the need to move it out of the Martian gravity well for use on a return trip. I don’t quite see an emergency return scenario. If you end up doing a fly-by instead of a capture as planned, it’s because the engines didn’t work...... If you use multiple engines, like I have proposed in using the upper stage engines for Tugs and vehicles, the firing time would be extended for those engines that still work, since they are independent a common failure would be eliminated. The Shuttle uses the same scenerio, one OMS engine fails the other one fires for a longer period. If the mass of your transit vehicle requires six or eight engines that would be quite a bit of redundancy. If you do a flyby of Mar <div class="Discussion_UserSignature"> </div>

ldyaidan · May 10, 2005

As far as getting the schools involved, I'm still planning to start a thread on that subject. If anyone has any ideas, let me know. Also, we're going to be starting an aquaponics project, as well as a solar energy project fairly soon, and try to involve some of the local schools. These should prove to be interesting, and may be a project for school involvement in other areas. Would it be possible to have the "greenhouse" as part of the ship, to be used on the trip, but also have it as a detachable part, that is dropped, in full onto the surface to be integrated into the overall settlement? That way it is already set up and producing when it gets there. Rae

spacester · May 10, 2005

. . . why bother with a reactor? Uh, cuz we need a lot of power and solar is not feasible on Mars. Are you thinking about some other source of energy that I'm not remembering? multiple engines . . . a common failure would be eliminated. Yeah, we're planning on multiple engines and propellant margins, so the likelihood is very very small, but you still have to consider the failure scenario. That's all I was trying to do, for manned missions mostly, but if a cargo mission with hard to replace equipment does a partial burn, we would want enough extra dV to come around again to Mars. The failure mode would likely be a premature engine shutdown coupled with the inability to start another engine in time to make the correction. This would alter the heliocentric orbit so you would be looking at getting those engines going as soon as possible to make another burn to embark on a new transfer path to rendezvous with Mars or Earth. A prime reason to have dV margins for manned missions. [Scott, would you mind using quotes or something so we can more easily tell who is saying what?] <div class="Discussion_UserSignature"> </div>

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