Let's Design a Settlement for Mars!

[scottb50]

That's ridiculous, the only way it works is with a cycler.<br /><br />First Mission: Takes surface facilities, orbital facilities, landers and initial crew from LEO to LMO. Main vehicle returns with samples and crew who are not staying after Second Mission arrives.<br /><br />Second Mission: Supplies, people and spare parts for the surface facility, vehicles as well as Modules, used to carry supplies and water enroute, to expand surface facilities or establish others.<br /><br />Susequent Missions, see Second Mission. I don't see a better way to build a colony, or even a research center. <br /><br />Beyond that. Who knows? Maybe Mars is a good place to visit, or off the beaten path, we don't know until we get there. Thats why I can't get that excited about a colony, until it evolves from a research facility into a colony, which Antarctic facilities haven't done in the last 50 years by the way.<br /><br />The only way to go to Mars, or the moon is with cyclers. The biggest problem is getting from the Earths surface to orbit. The rest is easy, or at least simpler. <br /><br /> <div class="Discussion_UserSignature"> </div>

 

[spacester]

Scott, what's your definition of 'cyclers'? <div class="Discussion_UserSignature"> </div>

 

[scottb50]

A core vehicle that goes from LEO to a destination orbit, or location in Space, and back. Modules are attached as needed for cargo or propulsion. <div class="Discussion_UserSignature"> </div>

 

[spacester]

Whew! That's a relief, I had to make sure we're off the Aldrin Cycler strategy. You and I are both just saying that in principle, everything should be reusable, especially the large hardware. Every major part of my Mars Fleet is reusable.<br /><br />Arobie, I almost missed your post! Excellent work, I see no problems with that after a quick look . . . I like the taxonomy system a lot, it fits nicely with other stuff we haven't talked about . . . gotta run . . . <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

Dan<br /><br />I am not sure why you think I argued for water as shielding, because I did not. However, since you mentioned it.... <br /><br />Keep in mind that whatever you do on Mars in orbit or in transit you are going to keep large amounts of water, of the order of 25 kg per person per day. So it makes sense to use it for shielding where practical and neccessary. It is also very attractive to recycle it. As I recall the ISS operates at 90% efficiency in this regard. This cuts the net daily usage to 2.5 kg PP.<br /><br />Jon<br /><br /> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[JonClarke]

probably bets to call these spacecraft shuttles or ferrys rather than cyclers, because cycler means a very specific type of spacecraft that uses a very specific class of orbits. Just to avoid confusion.....<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[spacester]

Thanks for that, Jon, but we've got Martian "Shuttles", a more powerful variant of a Hopper. I don't like "Ferrys" because the propulsion stage doesn't have passengers or cargo, it just pushes stuff around.<br /><br />I've chosen to call it an Interplanetary Booster Stage. It's taking the terminology from launch operations and applying it to interplanetary voyages. So it's a Booster, but of the interplanetary type. The name is meant to imply a multi-staged vehicle where the first stage does as much of the work as practical.<br /><br />The second stage is a spin-g craft with dV for Mars orbital operations, if manned. The cargo variant of the second stage either goes all the way to the surface or hands off to a sister ship, a second stage from an earlier cycle converted into a Martian Cargo Shuttle Propulsion Stage. <div class="Discussion_UserSignature"> </div>

 

[spacester]

Jon, I'm glad we're on the same page on taking lots of water.<br /><br />On the basis of 25 kg / day / person, does anyone want to calc the volume and mass of water we need for 28 people for 250 days? (200 days transit, 10 days transfer, 40 days contingency)<br /><br />Martian surface shielding (not already incorporated in the habitats) should be from ISRU - regolith and ice. There will be plenty of time to get the first, trial hab covered, because it's supposed to be ready and running when the first people get there. The settlers would then assist the robots in covering the habitat delivered for the current cycle. <div class="Discussion_UserSignature"> </div>

 

[arobie]

Spacester,<br /><br />For 28 people / day:<br /><br />700 kg / liters water<br /><br />Calculating for 250 days is a bit tougher. That depends on the efficiency of our water recycling unit(s). <br /><br />Without water recycling, we would have to lug 175000 kg / liters of water.<br /><br />I'm going to give our water recycling unit a 90 percent efficiency. (Based off of the ISS)<br /><br />That means that we need to supply enough to make up 10 percent lost every day.<br /><br />10 percent of 700 is 70 so:<br /><br />y = 70x + 700<br /><br />y = amount of water<br /><br />x = days<br /><br />y = 70 (250) + 700<br /><br />y = 18200 kg/liters<br /><br />Note: 1 kg of water = 1 liter of water<br /><br />Kilograms were orginally based of off 1 liter of water. Since water varies due to temp and pressure, it's not exact, but really, really close. 1 kg H2O = 1 liter H2O is close enough for our purposes. Thank you Dan_Casale and Tap_Sa for teaching me that. <img src="/images/icons/smile.gif" />

 

[spacester]

Nice work. Now, if we determine the diameter and height of a 14-person habitat, we can figure out how thick a layer of water we could have around the entire cylinder, plus flat end caps,using the entire 175 tonnes of water. I'm thinking the inflatable habitat could have a water blanket layer.<br /><br />Or maybe, even if we bring the entire 175 tonnes (just as a benchmark - for the sake of discussion), it's enough only for a "fallout shelter" - a refuge everybody gathers into during a CME from the sun.<br /><br />How big of a cube could we build using 175 tonnes of water filling walls 0.50 meters (19.7 inches) thick?<br /><br />In what way do we utilize the water we bring? In storage as shielding? Strictly as a CME refuge? Aquariums / Aquaculture? Hot tubs? Hot showers?<br /> <div class="Discussion_UserSignature"> </div>

 

[arobie]

Spacester,<br /><br />Before we get too far, we have a decision to make.<br /><br />With the 25 kg/person/day we now have two different figures for water consumption, this one from Jon_Clarke, and Dan_Casales figure of 6 liters a day for drinking, food prep, and hygine and 40 liters a week for laundry and showers. Dan's works out to about 12 kg/person/day while Jon's is 25 kg/person/day. That's a big difference.

 

[tap_sa]

A question: Does the 90% water recycling efficiency based on ISS include or exclude the O2 generation? 2.5L water loss per day per person sounds quite alot, where does it go. It's a closed tin can after all so it cannot just evaporate away <img src="/images/icons/wink.gif" /> If water is not used to O2 generation by electrolysis then recycling efficiency might be much higher. But then we would need true O2 recycling where CO2 is cracked, doable but AFAIK not applied in space before.

 

[arobie]

Tap_Sa,<br /><br />All good questions, and honestly, I don't know the answers.<br /><br />I just took Jon's figure for water per day and figure for ISS efficiency and ran the numbers.<br /><br />He would probably know the answers to your questions.

 

[spacester]

Hi Arobie, good point.<br /><br />IIRC, Jon's numbers are a water-rich scenario, Dan's are based on a conservation strategy. My design habits tell me to provision for the former, but operate for the latter.<br /><br />My idea is to bring enough water that if the recycling fails the first day out from Earth, it's not a problem - you just use up all the freshwater you brought at a modest rate. But in fact you strive for a high recycling rate - in the extreme case, you would arrive at Mars with as much pure water as you left with. But you would not design for a cutting-edge recycling rate.<br /><br />This is one way to keep costs down. You would be in a position to design your recycling unit without the mission-critical aspect dominating the design. It would still be robust, but not have to achieve a very difficult performance standard. <div class="Discussion_UserSignature"> </div>

 

[spacester]

Excellent question, Tap_Sa . . .<br /><br />We need the answer to oxygen generation for a closed system. That's the unit that's been having lots of trouble on ISS right?<br /><br />Is there any chance photosythesis could do the job of daily oxygen generation? <br /><br />Design concept: duckweed in shallow racks under strong lighting.<br />Question: How many square meters would be needed to support 14 people? <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

There is no "right" answer for water consumption. In a survival situation you could probably get away with 3 L per day PPP. That is basically drinking and food hydration and nothing else. How we calculate the everything else is where the different numbers come in. It is fun to actually measure your own daily water consumption in various areas and see how little you can get away with. Some uses of water in a closed environment (and I am using the numbers from memory, I can get a reference from my work computer tomorrow):<br /><br />Drinking - 2 L PPD<br />Food hydration - 2 L<br />Food prep - 2 L<br />Teeth cleaning - 0.5 L<br />Daily sponge wash (essentials only) 2L<br />Toilet cleaning - 1.5L<br /><br />The heavy users of water are everything else. These include:<br /><br />showers<br />humidification<br />environmental cleaning<br />clothes washing<br />cooling<br /><br />Even showers are variable. Is it a full domestic shower or a navy shower? In a clean environment (in transit) you can get away with a shower once a week. In a dirty environment, like Mars I suspect you will need them several times a week. Also keep in mind that in zero G you can do a lot of cleaning with good air filters. On earth (or mars) the airborne materials settle to the surface and need to be removed by clean materials and elbow grease.<br /><br />Having just crunched through consumable numbers for a paper I would be happy with Dan's 12 kg for transit and 25 for Mars. However, if you add in food production and biological recycling these numbers go through the roof.<br /><br />Some other points raised by others:<br /><br />The 10% daily loss goes in various ways. All spacecraft hulls leak, as do radiators. Some is lost in EVAs, via the airlock, suits, and suit cooling. No recycling system is 100% efficient. for example if you recycle wash water you are left with a sludge of skin cells, oils, hair, etc. Recovering water from this sludge, as it is from faecal matter is difficult. Flash evaporation i <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[arobie]

<font color="yellow">How big of a cube could we build using 175 tonnes of water filling walls 0.50 meters (19.7 inches) thick?</font><br /><br />A cube with an inside volume of 362.77 cubic meters. Length, width, and height are 7.132 meters. The layer of water sheilding is outside of that.

 

[scottb50]

Where I see a problem is when you talk of using Kerosene and Methane. I see no need for either, not only are they more difficult to store than water, they both breakdown chemically, over time and reduce, or lose, their efficiency. Hydrazine is even worse, heavy and at least as hard to contain as Hydrogen.<br /><br />First, the problem with storing Liquid Hydrogen is solved by not producing it until near the time you need it, loses could be kept low and any boil-off occurring could be recycled back into the main power supply for re-use until needed. Hydrogen containment would still cause loses, but, the key is to keep the water until you need it. Once the outbound and return requirements are actually established, payload, water, etc. it would be much easier to put numbers to ideas. <br /><br />For power generation LH is not even a requirement, Hydrogen can easily be contained under low pressure, even now, and used to power fuel cells and thrusters. The real determinator is the Oxygen anyway, rather than the Hydrogen. 8+1 or 8+6+1, figure in the efficiency difference and hydrocarbons start looking worse and worse. <br /><br />Water does present a problem in Space though; if it freezes it expands, which would be a very hard system to design, so it needs to be kept liquid. Heat generated within a vehicle would probably handle most of the problem, with solar power it would be pretty easy to keep a stable environment.<br /><br />The bottom line is water is easily contained and transferred with minimal environmental problems. <br /><br />Having more than one propellant just adds complexity. Hydrozine thrusters, LH/LOX engines to orbit, Kerosene enroute, Methane back. Lots of luck! <br /> <div class="Discussion_UserSignature"> </div>

 

[grooble]

About the water, wouldn't it be simpler and better to design some kind of self cleaning clothing? Or clothing that does not get dirty easily, and that removes bad smells? You could remove the need for brushing teeth by the type of foods on offer, and just bring a load of good chewing gum, or stick to mouthwash. Washing hair etc - no, everyone should have their heads waxed, including the females, in fact have all bodily hair removed. <br /><br />This would cut down water usage, and improve hygiene at the same time. <br /><br /><br /><br /><br />

 

[JonClarke]

Invent self cleaning clothing and the world will beat a path to your door. Until then we wash them. Cleaning your teeth needs maybe 0.5 L of water, hardly a big issue. Depilation is a bit drastic, I suspect, and not neccessary.<br /><br />Of course we might we decide to go dark ages and never wash......<br /><br />Jon<br /><br /> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[grooble]

There are people who WOULD put up with those conditions though, tougher, rougher people, not your squeeky clean *where is my hairspray?* type. You need those hardened people to make your settlement a success, people who can handle the hardship, normal folks may break. Look at folks in some of the hardest areas of the world, you want those toughened, strong people to be your settlers, afghans and the like. They can make hard treks that even our special forces cant make.<br /><br />

 

[grooble]

Also a quick tip about breeding, you'll need to send a sperm bank from earth in order to reduce inbreeding. That's just how it is. The women could have surrogate children, so the genetic pool is kept diverse. So there would be no real brothers or sisters. <br /><br />Perhaps that could be part of your mars lottery prize, have your genes saved and used on mars.

 

[tap_sa]

<font color="yellow">"You need those hardened people to make your settlement a success, people who can handle the hardship, normal folks may break."</font><br /><br />Good point. Pragmatic and adaptive people.<br /><br />One factor that affects the water issue is what the settlers are supposed to do while enroute. How much do they have to perform physical work (in addition to exercise to keep themselves fit) ? This affects greatly how much the crew consumes food, water, oxygen etc.<br /><br />How's this for water baseline; we start the trek with as much clean water as is minimum requirement for the crew to survive, assuming all water recycling equipment fails. Daily provision is the amount person has to consume to prevent dehydration, and just that. No shower, washing clothes/teeth, nothing but surviving. Quick googling tells the required amount is about 3 litres for average adult male and 2 litres for female. Assuming average 2.5L for 28 passengers we need 70L per day total, neatly the amount 90% recycling efficiency was loosing per day. So, if the recycling works, people can do a lot of nice things to add their comfort. If it fails, well then you have to be a little more spartan for a while.<br /><br /> Btw since the voyage lasts months, quite a lot of people in rather small craft, they all perspire, doesn't this all mean that air humidity control has to work or things get so damp inside the craft that it poses a serious risk.

 

[grooble]

I know this may sound funny but...Arobie said on another thread something about dwarfs, and i was thinking, what if the crew was made of dwarf & midgets? Surely that would bring down launch costs and they'd eat, drink less? <br /><br />Or you could put up more dwarf people for the same cost as a lower number of ordinary people. You'd have that extra brain / skillset for the same price.<br /><br />This isn't a joke, i'm serious..

 

[dan_casale]

Arobie:<br />I like your summary, lets see if I can expand it to include everything.<br />A) Vehicles Class<br />-----1) Earth to GTO - Cargo<br />----------a) Delta IV heavy - 10,843Kg to GTO - 5 meter faring - no info on length of payload.<br />----------b) Atlas-V-551 - 8,200Kg to GTO - 5 meter faring - no info on length limitations.<br />----------c) Shuttle - 28,800Kg to LEO - cargo bay 15x60 feet - Unknown amount (20,000?) to GTO.<br />----------d) Ariane 5 - 8,000Kg to GTO - 5 meter faring (assumed) - no length info.<br />----------e) No info on Russian launch systems. <br />----------f) Failure mode: Loss of craft results in relaunch of equipment and possible loss of Earth-Mars launch window.<br /><br />-----2) Earth to GTO - Manned - 7 day orbital capability for 28 people plus crew (30 total?).<br />----------a) Shuttle - 28,800Kg to LEO - cargo bay 15x60 feet - Unknown amount (20,000?) to GTO.<br />---------------I) 28 passengers - no gravity.<br />---------------II) water - 25L/P/D - Volume: 5,250 Liters. Mass 5,250Kg<br />---------------III) O2 - volume:322.56 liters Calculation7 * 28 * 1323 gaseous liters O2 / 860.8 = 1.536 liters LOX) Mass:238.98 kilograms (7 * 28 * 1.138 kg/liter)<br />---------------IV) Waste management - none<br />---------------V) food - 3.175Kg/P/D - Volume: ? Mass: 666.75Kg<br />---------------VI) personal items 100Kg/P - Volume: ? Mass:28,000Kg - Launch this item as cargo until GTO<br />---------------VII) Misc consumables - Volume: ? Mass: ?<br />---------------VIII) Communications: 2-way voice/video, telemetery<br />---------------IX) Electricity - APU or fuel cell.<br />---------------X) Recreation - none<br />---------------XI) Temperature control <br />---------------XII) Falure mode: Loss of any of the above items may result in an abort to Earth. Loss of craft causes miss of Earth-Mars Launch window.<br /><br />----------b) No info on Russian launch systems.<br /><br />-----3) Moon to GTO - Cargo - No info<br /><br />-----4) Interplaneta