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Mars Colonization Program
The entire program of Mars Colonization can be charged to the Commonwealth of Mars as part of its national debt which can be recovered later after Colonization is done and the mars industrial age is initiated. This economic recovery period may take a few hundred years beyond initial Colonization. The Colonization Population will be limited to ten million (the absolute maximum that could possibly be moved from Earth to Mars in a hundred years).
The Mobile Survey Team
Crew: 10
Mission Time: 20 Years
To be deployed in 2010 AD. Their task is to review the geological stability of colonization sites. Set up forward deployed systems. Travelling the entire planet of Mars one supplies/infrastructure landing site after the next until the colonization transports begin arriving in 2030AD. The mobile habitat will need to provide a stable and long term mobile base of operations that is pretty much indestructible and provides for the long term crew needs.
The Mobile Habitat
Mars Zeppelin: It provides the large capacity needed for a twenty year mission. It can carry food and tools. With a standardised cargo drop module any cargo can be redeployed to a target site. The Zeppelin functions well as a mobile habitat and cargo lifter. They can travel from one landing site to the next and set up the equipment anywhere on the planet as needed.
Once the colonization teams arrive, they can use the equipment to begin work on constructing underground cities where industrial processes can take place on a large scale and cities carved into mountains need to be built. And the Zeppelin can become a passenger and cargo transport between colonization sites.
Limits- It will need to be assembled by a crew of ten (on Mars), Filled with Hydrogen as processed by the equipment available. All components will need to be in easy reach for assembly. Dust storms, meteorites, and long-term exposure to solar radiation are major hazards to equipment and personnel and failure in this hostile Martian environment will be a disaster.
-Sean Robert Meaney, 30 May 2005
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So you want to fund a Mars program with debt. Shades of Enron. Many crooks have created shell corporations with limited liability for the purpose of incurring debt they have no intention of repaying. The most probable outcome of such a plan is to create media releases to get the public excited, lure investors, create massive debt while the founders of the shell corporation take substantial dividends for their own pocket, then at some point the shell corporation declares bankruptcy and the investors are screwed.
One of the primary purposes for going to Mars is to start over. To create a new economy without duplicating the mistakes of current civilization on Earth or carrying forward liability for mistakes made by our forefathers. Western governments on Earth have operated with a deficit, but are all experiencing major problems. Smaller countries have financially collapsed, and major countries like Canada and the US are paying a very large proportion of their Gross Domestic Product on interest. Those interest payments are paid with tax dollars. In Canada, 19% of all federal revenue goes to interest on the national debt. (It took some digging to get that figure. Every year the federal budget gets longer with more flowery language and fewer numbers.) Canada can brag it's the only country in the G-7 that maintained a surplus every year since 1997, however that surplus is now down to $3 billion and that's is designated a "contingency reserve" that if not spent will reduce the balance of the debt. The debt is $501.5 billion, even if they apply the whole $3 billion the debt isn't going anywhere quickly. US federal surplus is gone, it's back to deficit spending. One point the Canadian federal finance minister brags about is that foreign debt as a proportion of GDP has reduced while US foreign debt has increased to the point that as a proportion of GDP this year it's higher than Canada. Which ever country you want to model, it doesn't matter; debt is a mess. Don't duplicate that on Mars.
Another perspective: North America was colonized by Europe as a resource source. If Mars is to be colonized it must be a net revenue source for investors. That means short term profit. Long term profit is necessary, but you won't get the billions of dollars necessary unless there is short term profit.
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So once we are there even if only a flag and foot print first trip. What are the quick turn items found that mars has to offer for these kinds of investments?
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I wouldn't put such a gloomy picture on national debt as a concept, it can and should be used to stabilize economic fluctuation and pay for large short term investments that can be paid back over time. Debt is not inherintly a bad thing, but letting it get out of control is.
A Martian colony, for at least the first decade or two, will depend heavily on equipment developed, built, and shipped from Earth just to set up shop in such a fasion as to be "mostly" self-sustaining. That is, able to produce all the raw reasources (food, water, nitrogen, rocket fuel, basic polymers, base metals) so that nothing really "heavy" has to be sent from Earth except specialty items (computers, medical, nuclear reactors, turbines, portable solar cells, digging equipment, specialty metals/polymers). Hopefully even have an orbital fuel depot, and definatly have a reuseable Mars launch/landing vehicle.
Even then however, such a colony will still be incuring some billions of dollars yearly just to keep operating, much less the cost of sending new colonists. The cost for expanding a colony will be large enough that I don't think it will be possible for a Martian base to export anything to Earth costly enough to offset the expenses for a very long time. Operating the colony at a loss by home nation(s) on Earth or else the colonial government going into debt is unavoidable for the forseeable future.
In fact, other then some token export of Platinum, trinket Mars rocks/jewlry/etc, and the entertainment value (television, documentaries, "life on Mars" editorial reports) Mars won't have anything to offer the home planet... save one thing:
A chance to leave the Earth
Give your colonists a deal... you get a one-way trip to the Red Planet and the privilage of citizenship in return for all your Earthly wealth to pay your way and to help the place the function. People who want to go temporarily may do so, but will have to pay some large sum and not enjoy the bennefits of citizenship, as guest workers. If you want a way to "zero the odomoters" of a wealth-centric psuedo class society, this would be the way to do it... Nobody is there that doesn't have a commitment to the cause.
Something akin to a Social state will have to employed for the forseeable future most likly, where you would have ownership of personal wares but not property or profit, simply because operating the colony will be so expensive, and because big class divisions would be unhealthy for a society of only thousands of people.
There will of course be restrictions physically, psychologically, socially, and financially for who would be allowed to go and who wouldn't... one thing thats a grey area is what do you do with people who want to back out of it? The expense of sending them back to Earth would have to come out of the colony's budget, and when they do get back to Earth, would they demand a "refund" of similar size to what the comitted?
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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If we cut to the quick, I mostly agree with GCNRevenger.
That said, if Mars settlement becomes a race to spread selfish memes (will English or Mandarin or Hindi be the dominant language in the solar system 500 years from now?) Terran people may well voluntarily pay to help support Martian settlers.
Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]
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Donations Bill? I doubt they would amount to a whole lot.
No doubt that the colony would grow slowly after an initial "rush" of rich adventurers, but I think this is the one thing that Mars has of value to Earth is to "get away from it all." The one chance of a place where a social state would possibly work would have a big appeal to some I am sure, or simply doing something visionary instead of mundane with your life.
The big problem will still probobly be getting the cost "per seat" down low enough to pull this off. Expendable vehicles are out of the question, and probobly first-generation Earth reuseable RLVs probobly won't be cheap enough either. A next-generation "Shuttle-III" and a cycler powerd by something better than solid-core NTR engines is a must.
Another problem comes to mind... getting people willing to do what they are told when they get there. What job they will have, where they will live, if/when they are allowed to have children, and so on. It will be the most democratic state since Athens probobly, but people with "authority issues" could be trouble... Take a page out of the "Survivor" book and vote to send troublemakers home.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Short term, there are a lot of precious metals on M-type asteroids. Fuel cells for cars need platinum, not much but there are a lot of new cars built each year. I saw a news announcement that the same group that predicted US oil production peak has predicted the world oil production peak will be just a couple years. http://dieoff.org/page133.htm]This paper says the peak will be next year, falling to 3/4 by 2020. Alternate energy production will be big business, starting now.
Then there's fuel for satellites. That can be harvested from C-type asteroids. Supporting asteroid mining will be expensive. That can be done much more cheaply from Mars.
Then, yes, there will be migrants who want to go for their own reasons. Transporting settlers will be big business. The ship can only be cost effective from ticket revenue alone if it's built from in-space materials. That means asteroid and/or lunar mining for industrial metals sufficient for a colonist transport ship. That ship will also need fuel. Mining/manufacturing infrastructure can also build/supply hotels in Earth orbit.
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I think that you radically, deeply underestimate how much trouble it will be to mine or build anything from asteroids. I think its safe to say that it would be easier to mine platinum asteroid fragments and base metals from the Moon then it would be to bother with asteroids, despite the lower delta-V round trip requirements.
Gravity is that important
I also reject the notion that we have to build cyclers out of materials in space. No we do not have to, the answer is to reduce the Earth-to-orbit costs, not to bother with zero-G factories and mining. I think you may also underesitmate how light we could make a pretty large cycler if we have a propulsion technology efficent enough to abandon aerobreaking.
The fuel problem will also largely be solved by abandoning fifty year old propulsion technology and switching to something much more efficent. A GCNR for crew and/or nuclear/ion for cargo for instance, perhaps even fission/fusion VASIMR engines or beamed power thermal systems.
There is no need for any serious space infrastructure to support a Mars base, you may not even need a fuel/payload depot in Earth orbit if you refuel/reload cyclers directly.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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A chance to leave the Earth
Give your colonists a deal... you get a one-way trip to the Red Planet and the privilage of citizenship in return for all your Earthly wealth to pay your way and to help the place the function.
Sounds like a star trek episode, But you are right for money will have no value for those select few colonists..
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I have to disagree. Microgravity mining on asteroids is not that difficult. The only iron ore on the Moon is an oxide and mixed at that, such as ilmenite. That takes a lot of energy to smelt. Iron, nickel and cobalt exist on M-type asteroids as metal; the Mond process can easily separate them. Heat for Mond can be collected from sunlight by a mirror.
Aluminum is very scarce on an M-type (metal) asteroid, and an S-type (stone) asteroid has the same minerals as the Moon. Most stone asteroids have a mix of elements but some of them must come from the large asteroid that broke up to form M-type asteroids. M-type come from the core, S-type with concentrated aluminum and silicon come from the surface. Only 4% of near Earth asteroids are M-type, about that many will be S-type with concentrated aluminum. The Moon will have the same minerals as these S-type with high aluminum. If you claim it's easier to harvest aluminum from the Moon even though S-type asteroids require less fuel, then I won't argue. However, the smelting will make precious and ferrous metals much cheaper from M-type asteroids.
C-type (carbonaceous) asteroids are the only source for water, other than a planet. The Moon has so little it'll never be practical to harvest, and we know what it costs to lift fuel from Earth.
High-tech engines? Sure. High power ion engines have already been demonstrated in the lab at the Glenn Research Center, but you'll never get enough xenon gas for a manned mission to Mars much less a colony ship. Fusion is far from ready, we don't know if it'll work within our life time. Fission VASIMR could work, and nuclear thermal whether solid core or gas core would definately. VASIMR and nuclear thermal still need liquid hydrogen propellant.
If you're trying to argue that a manned mission to Mars can be done simply and now, I have to agree with you. A manned science mission doesn't need infrastructure, but if you design the ITV and space taxi to be reusable then the first mission leaves behind infrastructure to make subsequent science missions cheaper. However, colonization is another thing entirely. Reducing the per passenger cost will require a large vehicle (~100 passengers) and the infrastructure I mentioned.
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If cargo payloads track a weak stability boundary trajectory (the so called "Lo Roads") no exotic propulsion is needed. Just a supply chain pipeline filled with modules. Change the ratio of "LEO mass" --> "Mars delivered mass" from 1/5 to 1/2 or better and the capital expense of exotic propulsion may not be justified at least for cargo.
The slow boat to Mars will replace the slow boat to China in story and song.
Earth to LEO remains the big price component, not LEO to Mars, at least for cargo.
Edited By BWhite on 1117565934
Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]
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No way, the problems inherint with doing anything of any scale in zero gravity besides docking modules together are so great that zero-gravity asteroid mining is a fools' errand. Building big things without gravity is very hard, and mining will be even tougher. Nobody even has a bright idea of how to get chunks down to a reasonable size, and smelting the finished product (metal carbonyls from mond or metal vapor from microwave smelting) into useful shapes will be impractical since you won't have gravity to induce deposition. And no, a giant centrifuge is not a good solution for gasses. The fact also remains that asteroids of large size have crashed into the Moon, and have not actually left the Moon. They are still there, perfectly preserved under the dust, waiting for us to dig them up... Maybe one would even be a C-type asteroid the size of a moutain. With really, truely efficent launch methods (perhaps even space elevators) then Hydrogen supply shouldn't be a show-stopped for Lunar mining.
But anyway, asteroid mining is also a bad idea because it isn't nessesarry, a Mars cycler for a small colony won't need to hold a hundred people (say, 25ppl), since they won't be coming back, and it is easier to simply build several small cyclers on Earth then one big one in space. Space construction really is that hard, and it isn't going to change for a long, long, long time. Multiple small cyclers will also be better matched to RLVs anyway (on both ends), so you don't need so many docking events per trip. There aren't ever going to be any huge (>25MT I figure) RLVs, because there isn't any justification for them.
High-Isp engines are non-negotiable for a small (a few 1,000's) Martian colony. GCNR or advanced fission VASIMR are the best options on the table at the moment for crews (GCNR having higher thrust, is simpler and lighter but VASIMR having higher max Isp and extra energy) and are so effective that you simply wouldn't need asteroid fuel to be practical. For cargo you could get away with fission/ion, but the reactor would have to operate at high power for an awfully long time to be practical. Widening the launch window to permit departure anually rather than every other year should also be a requirement, even if that means somewhat longer transit times.
These cyclers will not be huge ships made of metal, they will very likly be made from composit structures on Earth of various type, rigid graphite based ones for fuel tanks (including liquid hydrogen) and inflatable polyaramide ones for the crew cabins. Only structural members, docking adapters, and the engines would be made of metal, futher eliminating the usefulness of asteroid space materials.
With Shuttle-III (SSTO Scramjet RLV with 25MT of payload or 25 crew) there are no more excuses not to simply bring up the stuff from Earth and get on with it, ELIMINATING as much in-space infrastructure as possible from the needs of a colony should be a goal, not something to be avoided. As long as we can send a few hundred people a year and a high-hundreds/low-thousands of tonnes of payload, thats fast enough. Colony building should go slowly, taking time to integrate the colonists into their new society before flooding them with newcomers, taking time to build up raw materials with limited industrial capacity so you can build their homes and gardens, and to give us time to work the kinks out of building a new kind of colony... something we haven't done in centuries. It will not be a quick six-year process, nor should it be, this is a 20-25 year commitment.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Getting water out of an Asteroid could be accomplished by the delivery of an automatic miner. It would initially bolt itself to the outside of the chosen target, by use of chemical,mechanical means and then deploy its solar panel electricity supply. Then the automatic miner can drill into the Asteroid and by use of heat evaporate the water etc to be stored.
As to actually mining the materials in the Asteroid that is a lot harder. Still there has to be a way to actually get the materials without the benefits of gravity.
Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.
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In space construction should go well with the tether ballast station of that 500km long tether, which will have artificial gravity as a byproduct of the rotation. There are products that also can be made more efficiently in vacuum, or at the central module (where the solar cells are) in 0g.
I agree on the need for nuclear powered engines for the crew transport cycler, but the easiest way for cargo is to sling shot it with the tether.
A full scale space elevator has a number of difficulties like being so awfully long and thus very difficult to maintain (micrometeorite/space junk impacts and the like), or having to be very massive before it can lift any heavy cargo, or the transfer time until the cargo reaches its upper end or GEO. But I don't say it can't be done, just seems to be much harder to do than a rotating tether.
A space based infrastructure is probably not unavoidable for a Martian colony, but surely it would make things much easier.
GCN, you seem to be quite optimistic about the performance of scram jet engines, maybe you could give some data on estimated ISP and additional drag losses compared to a conventional rocket engine?
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It does make sense to use a cycler to deliver and return large cargoes between Earth and Mars as it comes down to efficiency. And since most cargoes will be going just one way and that is too mars the cycler can be refueled from the asteroid belts C type asteroids and return practically empty. Of course in Earth vicinity it can pick up the cargoes heading to Mars and the next colonists.
Still it all comes down to the goverment or goverments that has the political and financial will to actually go with a Mars colonisation plan.
Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.
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A C-type asteroid is the easiest to harvest of all. Just land a drilling rig on the surface, punch large pegs into the surface to hold the feet, then drill a pipe. Once you hit ice use a heating coil at the bottom of the drill pipe to melt ice. At first it'll sublimate, but vapour in the crack between pipe and shaft will freeze, sealing it. Steam pressure will build until it's above 6.12 millibar (triple point of water) then liquid water will form. Steam pressure will push liquid water up the pipe. If you're concerned about running out of ice at one spot, use an outer pipe that closely fits around the drill pipe but doesn't spin with the drill. Ensure the two pipes have a pressure seal that permits the inner drill pipe to spin and slide. Ice will seal the outer pipe to the shaft, but you can drill deeper with the drill pipe to reach a new ice deposit and reposition the heating coil. What comes up the pipe will be mud. There will be clay, gypsum, Epsom salts, salts (sodium and potassium chloride), tar, as well as chondrules (pebbles). This stuff can be filtered out to get pure water. The mud could be baked at high temperature to extract every drop of moisture, turning the clay into a soft brick. Use a solar oven: parabolic mirror on a flat-black oven. Dump the brick-like slag on the asteroid surface. Water can be filtered with ever finer filters, then a reverse osmosis filter. As screen filters get clogged they can be spun in a centrifuge to clean them. The whole operation can be automated. Pure water can be split in a proton transport membrane electrolysis cell, powered by photovoltaic. A semi-permeable membrane can separate gas from water; it works in zero-G on ISS so it'll work on an asteroid. Then cryogenically liquefy the gasses with a pump, again powered by photovoltaics. Liquefaction pumps for zero-G have already been designed, intended for long-term storage an Earth orbit fuel depot.
If you want to get fancy you can extract CO2 from the mud. That would involve adding oxygen to the oven when mud is baked, and heat it enough to burn tar. A water only oven could separate mud from vapour with a semi-permeable membrane that won't degrade with heat, but if you want CO2 then you'll need to spin it, make the oven a centrifuge. The vapour would then be separated in a cooling centrifuge, liquefying water between +3 and 98°C. The gas could be completely dehumidified through pipes that have a rolling plastic tube liner, getting colder along its length from +3°C to -78°C. Ice would accumulate on the liner, but the liner would move opposite to the gas, back into the warm tank where frost would melt. Dry gas would accumulate in a non-spun chamber frozen below -78.5°C which would freeze CO2 into dry ice frost. Colder would reduce partial pressure of CO2 gas, freezing more into dry ice, as long as it remains above the -182.96°C liquefaction temperature of oxygen. 170°k (-103.15°C) at 10 bar pressure provides good dry ice production. A platinum catalyst can aid hydrocarbon combustion, decomosition of ozone into oxygen and CO into CO2. A press would compress the frost into a brick, squeezing out oxygen gas. The whole system would be pressurized and connected to the oven so oxygen would flow back to the oven. As oxygen is consumed, more would be added from water electrolysis. Hydrogen from tar would form water, but that would go with baked-out water into the electrolysis tank. Again, totally automated.
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It does make sense to use a cycler to deliver and return large cargoes between Earth and Mars as it comes down to efficiency. And since most cargoes will be going just one way and that is too mars the cycler can be refueled from the asteroid belts C type asteroids and return practically empty. Of course in Earth vicinity it can pick up the cargoes heading to Mars and the next colonists.
Still it all comes down to the goverment or goverments that has the political and financial will to actually go with a Mars colonisation plan.
Grypd, if a cycler is tracking a free return orbit (more or less) being "full" or empty" would seem largely irrelevant. Mars orbital capture and landing will require delta V - - going back to Earth's vicinity will be "free" - - no?
Solar thermal rockets (for example) can be used to incrementally adjust trajectories to remain "free return" meaning fuel requirements are minimal.
As far as re-using rockets, what about landing RL-10 propelled payloads on the Mars surface, refurbish the engines and send them back to Earth?
Edited By BWhite on 1117584524
Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]
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As always, its never that easy, and its -doubly- not that easy to do in zero-g...
"punch large pegs into the surface"
Can't, no gravity to push against... I don't think you fully realize just how low the gravity of your average NEA rock is. Its basically zero, you could literally jump right off the thing, and you'd have a pretty terrible time trying to walk.
I also think you are going to run into some terrible problems with clogging if you find any regions with low water concentration if you run into any tar. This isn't such a problem on Earth or Mars because the water ice was deposited as a "water table" and is pretty uniform, but asteroids have no such bennefit plus the problem of tar clogging.
Then there is the issue that since the asteroid is probobly not a contiguous solid, and is just a loosely held together pile of salty charcoal and ice, that you can't go creating a hot steam bubble in it and expect it not to leak or explode. If it does either one, then the drill-and-pump mine is done for.
"Dump the brick-like slag on the asteroid surface"
Its questionable if you have enough gravity to do this either, that pile of slag isn't going to be very stable given the low gravity.
You are also going to need a whoooole lot of energy to do this on any practical scale, and great big solar arrays will be tricky to set up if your rock happens to be spinning... that would make docking a real nightmare too, since there wouldn't be enough gravity to "land" persay.
But more then that, there really isn't a good reason to do this. A real-real "no kidding" RLV will make transporting Hydrogen to orbit so cheap (a million dollars a tonne, perhaps less) that it just doesn't make any sense to haul it from all the way out there for all this trouble.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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It does make sense to use a cycler to deliver and return large cargoes between Earth and Mars as it comes down to efficiency. And since most cargoes will be going just one way and that is too mars the cycler can be refueled from the asteroid belts C type asteroids and return practically empty. Of course in Earth vicinity it can pick up the cargoes heading to Mars and the next colonists.
Still it all comes down to the goverment or goverments that has the political and financial will to actually go with a Mars colonisation plan.
Grypd, if a cycler is tracking a free return orbit (more or less) being "full" or empty" would seem largely irrelevant. Mars orbital capture and landing will require delta V - - going back to Earth's vicinity will be "free" - - no?
Solar thermal rockets (for example) can be used to incrementally adjust trajectories to remain "free return" meaning fuel requirements are minimal.
As far as re-using rockets, what about landing RL-10 propelled payloads on the Mars surface, refurbish the engines and send them back to Earth?
Ummm, free-return is not "free" by any means, free is simply referring that you are letting the suns' gravity do alot of the work so that you can depart from Mars at any time without any extra fuel compared to regular HTO. You still have to burn considerable fuel to leave Mars orbit.
No Bill, the vehicle used on the Mars-to-Mars Orbit and back must be reuseable AND stationed on Mars. This is the only way to sufficently leverage Martian propellant production in order to hold down the per-sortie mass of each cargo trip.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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"punch large pegs into the surface"
Can't, no gravity to push against...
Solid rockets in the top of the spikes; don't need gravity.
I don't think you fully realize just how low the gravity of your average NEA rock is. Its basically zero, you could literally jump right off the thing, and you'd have a pretty terrible time trying to walk.
NEAR (Near Earth Asteroid Rendezvous) landed on the surface of Eros on February 12, 2001.
I also think you are going to run into some terrible problems with clogging if you find any regions with low water concentration if you run into any tar.
Steam flush.
Then there is the issue that since the asteroid is probobly not a contiguous solid, and is just a loosely held together pile of salty charcoal and ice, that you can't go creating a hot steam bubble in it and expect it not to leak or explode. If it does either one, then the drill-and-pump mine is done for.
I'm counting on a big one. Tens of metres of ice, clay, tar, and pebbles will hold together very strongly. Ice gets very strong when it's very cold. I'm also counting on size to conduct heat away, keep the crust cold so it doesn't blow out.
"Dump the brick-like slag on the asteroid surface"
Its questionable if you have enough gravity to do this either, that pile of slag isn't going to be very stable given the low gravity.
You are also going to need a whoooole lot of energy to do this on any practical scale, and great big solar arrays will be tricky to set up if your rock happens to be spinning... that would make docking a real nightmare too, since there wouldn't be enough gravity to "land" persay.
Again, NEAR landed on Eros.
But more then that, there really isn't a good reason to do this. A real-real "no kidding" RLV will make transporting Hydrogen to orbit so cheap (a million dollars a tonne, perhaps less) that it just doesn't make any sense to haul it from all the way out there for all this trouble.
I think you underestimate the cost of a hypersonic SCRAM jet spaceplane. It will be much cheaper than today's launch vehicles, but you want to use it for bulk fuel? Even if you got launch cost down to $100/kg it may be $20,000 per person after you include seats, pressure hull, air lock, life support, etc. Then add terminal cost, passenger training (similar to astronaut training), flight attendants, etc. and ticket cost can reach $50,000. For an orbital tourism trip that may be Ok, but $100/kg for fuel! Liquid hydrogen cost $2.75/kg delivered by truck to KSC in the early 1990s, or $2/kg delivered by barge to Marshall. That's one hell of a mark-up for fuel in orbit. Don't you think an asteroid mine would be much cheaper?
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Rockets won't provide you with the fast, sharp impact with enough accuracy. If you are just shooting peiton missiles at the rock, who knows what you'll hit... You might even bounce off.
Eros didn't so much "land" on Eros as "was just barely captured by" Eros. Just look at the extremely lazy orbital velocity... I don't think you can count on anything heavy staying put where you drop it unless its literally tied down.
"Tens of metres of ice, clay, tar, and pebbles will hold together very strongly"
No it won't, thats "high-g thinking," there isn't any kind of force to hold it together hardly. Ice is also quite brittle, and I would imagine it is especially so if it is an amalgum with sand and small rocks. Low-G worlds don't work in any sort of analagous fasion as high-G ones, you can't even use the same assumptions or think of them the same way... which is one reason why think it will be far harder then you imagine.
"Steam flush."
If you can get the pressure high enough without the water vapor liquifying in the ice cavern, since you won't be able to get it too hot as the supercold cave walls will wick away the heat. And if you can get it high enough without blowing off that side of the asteroid in a steam explosion. That would ruin your day.
Why yes, I do actually hold that much faith in a future Shuttle-III vehicle. A true SSTO vehicle will completly rewrite the paradigm of orbital launch since so little effort will need to be placed into preparing the vehicle for flight. It will be tremendously expensive and difficult to make it sufficently high performing and robust, but I think that it can be done, and barring the creation of a space elevator will have to be done. Flight rate here is key, that if you can fly such a vehicle often enough then the unit price for payload falls sharply.
Such a vehicle will be easier for human travel then you think too... no radically different training is needed compared to fighter pilot training, the dynamics will be gentle enough and the vehicle reliable enough that no "astronaut training" will be required for the passengers, and the trip short enough not to require special supervision.
And yes, launching fuel for $1,000 a kilo is a better deal then bothering with a an expensive and risky asteroid mine. Why? Because you won't need that much of it. Small cycler vehicles powerd by GCNR engines won't need that much fuel for the trip to Mars, they could get there for half the fuel mass that a conventional solid core engine could... A radical increase in Isp also changes the whole need for that rocket fuel you would have to try and mine.
These technologies are not here yet, they are not quite at hand, but we will need them anyway and will combined eliminate the economic advantage of mined asteroid water, especially given the host of things we don't know about zero-G mining that us high-G beings aren't used to thinking about.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Actually, the colder ice is the stronger it is. Mix in gravel and rocks together with -150°C and you have a reinforced amalgum stronger than sandstone or limestone. If you don't believe me ask the Deep Space 2 impact penetrators that went to Mars' south pole with Polar Lander. (Permafrost: smash! tinkle, tinkle, tinkle) The loose conglomerate theory of asteroids only holds if it's dry. If it is dry you don't want to drill that one for water. A prospecting probe will have to preceed any space fuel drilling rig.
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Even Phobos, which is ten miles in diameter, may not be big enough to build up very much steam pressure inside it, because its gravity is so low there is very little gravitational weight holding it together. Phobos is probably cracked and fractured pretty thoroughly because of 4.5 billion years of impacts, too. But even very low vapor pressure would be enough to extract a considerable quantity of gas over time.
I wouldn't aim to extract mud from the interior of an asteroid or Phobos, but gasses. I am not sure most NEAs have ice in them, but chondrite is 10% or so water of hydration, not to mention tar deposits. It would be easier to run a pair of pipes down the shaft--assuming you can get pipes into it--one for hydrogen and one for oxygen, with a spark plug attached and a large pipe for the exhaust gasses to escape to the processing plant at the surface. Pump down a mix of hydrogen and oxygen, burn them, and use the heat to drive off water from the in situ chondrite. Add extra oxygen to burn off the carbon or add extra hydrogen to methanate it. And perform this entire operation slowly so the exhaust gasses streaming up the shaft don't overwhelm the processing equipment on top or build up enough pressure inside to cause a blowout. That process would leave most of the solids in place. After you "turned off" the hydrogen-oxygen flame the residual heat would release additional gasses for days, also.
As for advanced nuclear electric or VASIMR for Earth to Mars transportation, will it really be cost effective? Let us say we can get hydrogen-oxygen fuel into low Earth orbit for $1000 per kilogram. We'll need about two kilograms of fuel for every kilogram of cargo sent to Mars (when you include the vehicle's mass itself), so it will increase the costs of cargo from $1000 per kilo to $3000 per kilo. A $2,000 per kilo cost increase corresponds to 2 million per tonne. How much will it cost if we use a $500 million dollar nuclear propulsion system to reduce the fuel consumption by half? If the nuclear power source can push 100 tonnes of cargo to Mars each time and is good for 5 trips, that's 500 tonnes of cargo; the $500 million engine has cost $1 million per tonne and has saved maybe half the $2 million in fuel costs, so it breaks even. If fuel from the moon or Phobos/Deimos is cheaper than $1000/kg, the nuclear engine will have to get pretty cheap to compete.
-- RobS
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It does make sense to use a cycler to deliver and return large cargoes between Earth and Mars as it comes down to efficiency. And since most cargoes will be going just one way and that is too mars the cycler can be refueled from the asteroid belts C type asteroids and return practically empty. Of course in Earth vicinity it can pick up the cargoes heading to Mars and the next colonists.
Still it all comes down to the goverment or goverments that has the political and financial will to actually go with a Mars colonisation plan.
Grypd, if a cycler is tracking a free return orbit (more or less) being "full" or empty" would seem largely irrelevant. Mars orbital capture and landing will require delta V - - going back to Earth's vicinity will be "free" - - no?
Solar thermal rockets (for example) can be used to incrementally adjust trajectories to remain "free return" meaning fuel requirements are minimal.
As far as re-using rockets, what about landing RL-10 propelled payloads on the Mars surface, refurbish the engines and send them back to Earth?
Ummm, free-return is not "free" by any means, free is simply referring that you are letting the suns' gravity do alot of the work so that you can depart from Mars at any time without any extra fuel compared to regular HTO. You still have to burn considerable fuel to leave Mars orbit.
No Bill, the vehicle used on the Mars-to-Mars Orbit and back must be reuseable AND Mars Colonization Program - Mission 1: Your Comments?] stationed on Mars. This is the only way to sufficently leverage Martian propellant production in order to hold down the per-sortie mass of each cargo trip.
By http://courses.ncssm.edu/math/TCMConf/T … t.pdf]free return I mean a trajectory that arrives in the vicinity of Mars and then Earth using gravity assists only. Such creatures exist but are difficult for Mars because of certain peculiarities in the Mars orbit. Aldrin cycler is another term that is used.
Tiny adjustments can be made by solar ion or solar thermal during the long passages between Earth and Mars and at Mars the colony simply does not stop, or even slow down - - one way settlers re-enter small capsules for aerobraking, aerocapture and landing while the more luxurious mother ship keeps going, with no aerobraking.
Perhaps the mother ship alters its course to stop at an Earth-Moon LaGrange point for another set of colonists. This way, tiny capsules (t/Space sized) can carry settlers from Earth to LEO/L1 and the colony ship and those same capsules are used to land on Mars while the six month journey is made feasible by living on board a larger ship.
With a genuine free return trajectory, the fuel needs are minimal to none. Mars Direct free returns are chosen based on propulsion failure.
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The linked exercise is to design a lunar free return, defined as the ability to return from the Moon without any propulsive engines burns after the trans-lunar insertion burn.
A Mars free return would return a spacecraft to Earth, after a Mars fly-by without propulsive engine burns.
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A http://news.uns.purdue.edu/UNS/html4eve … .html]2014 Mars free return trajectory that assumes main engine failure, thus very little propulsion is needed so that attitude control thrusters are sufficient.
Longuski and graduate student Masataka Okutsu discovered that the safest route to take would be one that permitted a quick return trip, via Venus, in case of an accident that forced the Mars landing to be aborted. The Martian gravity would bend the spacecraft's trajectory, hurtling it toward Venus, where another gravity assist would guide the ship to Earth. Because of the gravity-assisted trajectories, the spacecraft could make the return trip with only minor attitude adjustments from small thrusters, even if its main engine were disabled, Longuski says.
Using solar thermal, doing continuing burns between Earth & Mars, fuel consumption would be miniscule.
Edited By BWhite on 1117607050
Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]
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Perhaps the mother ship alters its course to stop at an Earth-Moon LaGrange point for another set of colonists. This way, tiny capsules (t/Space sized) can carry settlers from Earth to LEO/L1 and the colony ship and those same capsules are used to land on Mars while the six month journey is made feasible by living on board a larger ship
That is as long as you don't have to overhaul the larger ship, when a few small capsules of replacement parts might not be enough. It could still be effective if it could go for several trips without need for larger maintenance work, but having an engine to get into Earth orbit would make that one easier.
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