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It really is ideal stuff for a novel. Failing that, there are several thousand utopian communes scattered across the United States, and I am sure one could find a dozen or so people willing to create such a commune/colony, although I doubt they will be found here, and it sounds like there are few in the Mars Society as a whole.
-- RobS
The October 2002 issue of Scientific American has a mini-article about deflecting asteroids using x-rays, which cause the surface layer of the asteroid to vaporize and explode off the surface. They are testing the mechanism with a giant xray machine and tiny meteorite shards, down in New Mexico. The actual mechanism would use x-ray producing nuclear bombs.
-- RobS
I've been thinking about your idea in and around office work, a committee meeting, and a noisy four year old most of yesterday and today, and I have come up with a simple strategy for figuring out what masses we need. This is very rough, but it seems to work reasonably well. I have tried calculating masses needed to launch a certain amount of payload to Mars and the numbers I come up with never match those of the professionals. Usually my numbers come up too optimistic; the launch rockets end up being smaller than the numvers the professionals arrive at. So, instead of taking the problem as a physics problem to solve, I've taken the approach that it is a numbers game that has to reach the same results as the professionals. So, here's a "formula" that roughly does this:
#A. Payload to the Martian surface. Mass = 1 unit
#B. Landing legs, engine, parachute, fuel, aeroshell.
Mass = 1/2 unit
#C. LOX/LH2 propellant, tanks, engine to accelerate #A and #B from near escape to 3.8 km/sec (Hohmann transfer plus midcourse correction). Mass = 1/2 unit
#D. LOX/LH2 propellant, tanks, engine to accelerate #A and #B from near escape to 4.4 km/sec (fast transfer for crew plus midcourse correction). Mass = 1 unit
Note that if you just want to put a payload in Martian orbit, it is equal to #A plus part of #B (about 1.3 units)
Propulsion systems to get A, B, and C to escape velocity OR to get A, B, and D almost to escape:
#E. Solar Electric (solar panels, tanks, propellant). Mass = 1 unit
#F. Solar or Nuclear Thermal (solar panels and solar engine or nuclear engine, tanks, hydrogen propellant). Mass = 2 units
#G. Chemical (LOX/LH2) (fuel, tanks, engine). Mass = 3 units
EXAMPLES:
1. Placing a 25.2 tonne hab plus 4 crew on the Martian surface using chemical propulsion: #A + #B + #D + #G = 5.5 units; 25.2 x 5.5 = 138.6 tonnes. This is very good agreement with Mars Direct, where 25.2 tonnes is thrown to Mars by a 140-tonne to LEO booster.
2. Placing a 28.6 tonne ERV on the Martian surface using chemical propulsion (via Hohmann trajectory): #A + #B + #C + #G = 5 units; 28.6 X 5 = 143 tonnes. Again, in good agreement with Mars Direct, where 28.6 tonnes is thrown to Mars by a 140-tonne to LEO booster.
3. Throwing 46.2 tonnes to Mars (Hohmann trajectory). This is equal to #A and #B and requires #C plus #G. Cargo is 1.5 units, propulsion is 3.5 units. A unit thus is 46.2/1.5 = 30.8 tonnes, 30.8 X 5 = 154 tonnes. For Mars Direct, this requires a 140 tonne to LEO booster, so the calculation comes out somewhat high.
4. Throwing 40.6 tonnes to Mars (fast trajectory). Again, 40.6 tonnes is 1.5 units, so a unit is 27 tonnes; throwing it requires #D plus #G or 4 more units, Thus the total mass to LEO is 5.5 units x 27 = 149 tonnes, a bit high, but close.
5. Placing a 25.2 tonne hab on the Martian surface using solar-electric propulsion and fast transfer : #A + #B + #D + #E = 3.5 units; 25.2 x 3.5 = 88.2 tonnes. Energia! Of course, this does not get the crew on board; they’ll have to be flown up after the solar electric engine has done its work, and before the chemical engine in #D kicks the complex to Mars.
6. Placing a 28.6 tonne ERV on the Martian surface using solar-electric propulsion (via Hohmann trajectory): #A + #B + #C + #E = 3 units; 28.6 X 3 = 85.8 tonnes. Energia again!
Anyway, you get the idea. This seems to work pretty well; it’s at least in the right ballpark.
If the payload we want to land on Mars is in the 25-30 tonne range, we will need a launcher capable of putting at least half that into orbit; say, 17.5 to 20 tonnes. But even then, we would have to split the ultimate cargo in half, which would be very inconvenient and might require assembly in low earth orbit; and we would have to split the solar-electric vehicle in half, which raises the problem of launching liquid hydrogen into orbit and not using it right away. So I think we need a launcher able to launch 1 unit of Mars cargo to low earth orbit, which would also be able to launch the solar-electric vehicle intact.
Robert Dyke seems to be our expert about launchers; Robert, what are the real choices? Energia is best, but if it is unavailable, then what?
The other question to consider: can we make the hab and ERV lighter in mass than Mars Direct does? If we use an inflatable hab, a Mars Ascent Vehicle, and an Earth Return Vehicle (from 1-sol elliptical Martian orbit), we can probably reduce the 1 unit of surface cargo to 18-20 tonnes. But now we are sending three complexes to Mars instead of 2, each requiring at least three units of mass, so that’s a minimum of 9 launches instead of 6.
-- RobS
Actually, Robert, it occurs to me that the question "how few launches can we reduce it to?" has already been answered (though I am in favor of thinking about the question anyway). The NASA Reference Mission's solar-electric variant can be done using three Magnums, and the Magnum has a slightly smaller throw weight than an Energia (85 tonnes versus 88), so we know three Energias can do it.
Zubrin, in *Mars Direct,* page 105, says that nuclear-thermal rocketry can throw 60-70% more to Mars than hydrogen-oxygen, and solar-thermal can throw 40-50% more. If you want to keep the throw weight constant, this translates into smaller launchers: thus a 140-tonne launcher for hydrogen-oxygen can be replaced by (roughly) an 84-tonne launcher using nuclear thermal and a 97-tonne launcher using solar-thermal. Solar-electric should be somewhere between the two at worst, and more likely it is closer to nuclear-thermal. So an Energia, with an 88-tonne throw weight, is about right.
If the Michael Duke et al model for lunar transportation is assumed, a 29-tonne solar thermal unit can push 58 tonnes to the Lagrange point, where a small chemical stage can push something like 42 tonnes to trans-Mars injection (this is rough and off the top of my head). Zubrin's chemical booster pushes 46.2 tonnes of cargo and 40.6 tonnes of manned vehicle to Mars (less for people because they have to go faster).
So again, an Energia is about right.
Then there's another trick to remember: Mars Direct presupposes one launch the first opposition and two the second and each subsequent opposition. If we presuppose two launches during the first (unmanned) opposition, we can land a cargo pallet on Mars in the 15-25 tonne range, in addition to an ERV. Even if the throw weights to Mars were somewhat less with Energia/solar electric, that extra launch makes a big difference. Subsequently two launches are more likely to be enough because (1) after the first crew arrives, you already have two reactors and don't need more; (2) you probably have access to water, and thus do not need to import hydrogen feedstock; (3) you already have a hab and lots of stuff; etc.
-- RobS
Actually, Robert, I think we agree. You have convinced me that Energia is the best choice (barring political issues, which unfortunately will affect the choice). I would like to work on a redesign with you; it would be fun. I suppose we would want to start with the NASA reference mission? The problems is that I am no expert on figuring out masses; I have to rely on existing guesses and make extrapolations from them.
Here's a question for you: if a nuclear reactor will be needed on the Martian surface, would it make sense to use that same reactor to power a nuclear-electric (rather than a solar electric) vehicle? Unfortunately, I am uncertain how one would go about figuring out the answer. One would have to consider the masses of heat radiators (which may have to work differently on the surface than in space) and the problem of moving around something that, once it is turned on, has become radioactive. Reactors are not particularly radioactive before being activated, I gather.
Another, important question: are we talking about electric drive to, say, a Lagrange point (delta-vee, 3.1 km/sec), and then chemical propulsion thereafter? This is reasonably fast and mass-efficient.
-- RobS
Regarding having children on Mars, here's some new research about fertilization of embryos in low gravity:
http://www.space.com/news/space_pregnan … 18_wg.html
The Japanese researchers say mice embryos can be fertilized and will implant in zero gee, though the spontaneous abortion rate may be higher.
Space.com also has a nice article about the Mars Bio satellite to be launched in 2005.
-- RobS
Don't forget that every time a rocket is launched from Baikonur, first stages are dropped on someone's house. No one has been killed yet; no houses have been squashed yet; but livestock have been killed. It is a lousy choice, launching from the desert center of the world's largest continent, and too far north to get into an equatorial orbit as well.
--RobS
It sounds like the obvious thing to do would be to build a new Energia facility at Kourou and launch from close to the equator, which would probably boost the throw weight to LEO significantly (10%?). Energias launched from Kourou and the current NASA reference mission (designed for an 80-85 tonne Magnum, so the Energia makes a good substitute) sound like the perfect elements for an international mission to Mars. Maybe too perfect, since NASA will probably want to use American rockets and Kennedy!
-- RobS
I could easily see a Martian settlement, as it gets larger, building some sort of aesthetic meeting place, where interfaith services could be held, where different religious groups (they'd all be small at first) could hold their services, and where concerts and other cultural events could be held. Most likely, these would be held in the cafeteria at first, but once one can build out of brick or steel, the urge to produce a cultural and religious gathering place will manifest itself. There are two different approaches to take: (1) an enclosed approach that reduces radiation exposure, thermal loss, etc., and gives one lots of walls and a ceiling to decorate; (2) an "open" approach with as many windows as possible so that one can see Mars from inside and obtain lots of natural light (and Martian natural light will be pinker or more golden than on Earth, so it will have an aesthetic value itself). If the settlement were expanding every few years, they'd probably wait and build something large when resources are larger and construction experience greater. If the settlement were small and staying small, maybe they'd turn to an aesthetic construction sooner.
There are also specifically Martian things one could do to decorate a structure: (1) use ventifacts, strangely-shaped rocks as a result of wind erosion, as natural art; (2) make mosaics from a wide range of local materials (black basalt, whitish evaporites, sandstones in a range of colors from gray to red, orange, and yellow, dark carbonaceous rocks if they exist, fossiliferous rocks, etc.). The low gravity will also allow higher, wider interior spaces. I suspect local ingenuity could produce a unique structure highly suited for Mars or even for a particular location on Mars.
-- RobS
Robert, is there any price estimate for each Energia launch, and how much is it dependent on the assembly facility at Baikonur whose roof collapsed? Maybe you already answered these questions; if so, I apologize.
88 tonnes to LEO is quite significant. Three such launches equals 264 tonnes, which is equal to two 135-tonne to LEO launches that Zubrin advocates. Or, using solar-electric propulsion as advocated by Michael Duke et al., the 88 tonnes could be divided into a 30-tonne solar electric vehicle and 50 tonnes of payload, and the latter could be lifted to the lagrange point by the former. Two Energias would get 100 tonnes to L1, where the payloads could be mated. Then a third Energia with a chemical third stage could push a small (10 tonne?) capsule with the crew to L1 with about 30 tonnes to spare, which would be enough oxygen-hydrogen fuel to accelerate the whole thing to a delta-vee of 0.9 km/sec; added to 3.1, that's 4.0 km/sec, about enough for a seven month cruise to Mars. So three Energias could easily send Mars Direct on its way.
-- RobS
The article said some of the researchers want to examine scoops of moon particles, as they could include tiny fragments of Earth in them. A lot of the lunar samples still have not been examined in detail.
-- RobS
Space.com has an interesting article about the conference that is now ending in New Mexico about returning to the moon. Quite a few very capable scientists were there.
One article I found on space.com from June or July of this year, I think, made the interesting point that the lunar surface should be littered with rocks and dust blasted off the Earth. They even gave an estimate of 11,000 pounds per square mile (!) of terrestrial material. And almost all that material comes from the Earth's first billion years. It may very well be that the earliest terrestrial rocks with microfossils may be on the moon, since all the pieces of the Earth from that era were recycled here by plate tectonics long ago. Fascinating to think that there is terrestrial geology to recover from the moon.
-- RobS
It may very well be that an early piece of equipment to take to Mars will be a paper recycling unit, capable of chopping up old paper and making new paper from it! Paper is indeed pretty valuable. Computers have increased demand for it, not decreased demand. Indeed, a PBS special said the World Trade Center towers fell because of the fires the jet fuel started--the jet fuel all burned up in a few minutes--and that the fire was mostly office furniture and paper! If there had been truly paperless offices, the towers might still be there!
-- RobS
Regarding the Energia, I quite agree that it is a more practical way to get a Mars expedition on the way than using 24 tonne launches. But the 80-tonne Energia has never been built or launched. There is demand for commercial launches in the 20 tonne range and thus those rockets are mass produced and launched quite often. The point of my posting is that it may very well be that it is easier to go with existing launch equipment, and that it is possible to do so (though not convenient). If an Energia is built for Mars and moon launches, it probably will not be used for anything else, because right now there is simply no demand for launches in the 80 tonne range. Consequently, it may not be a cheap solution to the launching problem.
-- RobS
I'm afraid I am not tuned into their research. I read a summary on "Romance to Reality," David Portree's incredible website about exploration of the moon and Mars. I hope they publish something kore and we hear about it.
-- RobS
"At some point in the future, the Mars Society will build a prototype Martian settlement."
Actually, I rather doubt the Mars Society will do this. It seems to me the strategy is to go from habs to the translife experiment, then to a larger space-oriented project to demonstrate the Society's financial responsibility and scientific capabilities. A "prototype Mars settlement" would involve the Society in all the negative publicity that Biosphere 2 got: that its science is poorly thought through, its goals are driven by "dreams" and "emotion" rather than by reason, etc.
No one can predict the social structure that might arise on Mars through a small prototype here on Earth. An attempt will drive away many sober-minded people and it could look premature. The best "settlement" to aim for is the one on Mars.
-- RobS
I think the "greenhouse" was supposed to be a slice through a long cylinder that someone proposed for Mars. I don't think it resembled the Arthur C. Clarke Greenhouse being taken to Devon Island. The literature explained it had a very practical purpose for the Devon and Utah sites; processing gray water. Sewage treatment would be an ecological problem at the Devon Island site, so it makes sense.
-- RobS
I think there are several "obvious" reasons why a plan like this isn't being implemented yet:
1. NASA is committed to completing the International Space Station, and it has to do that first. Low earth orbit stuff is perceived by the vast majority of the people in NASA and probably by the pub;ic as well as more relevant than the moon or Mars.
2. If this were done using the space shuttle, it would be much more expensive--about four or five times as expensive--and the shuttle is no longer allowed to lift cryogenics in its cargo bay (this was a rule implemented after the Challenger explosion). NASA wants to build a second generation shuttle, anyway, so any plans like this have to wait for that second generation shuttlle.
3. Relevance. We may think humans to Mars is essential, but the general public is lukewarm.
4. Lobbying. Within NASA, is moon people versus Mars people, nuclear versus chemical, weigtlessness versus artificial gravity. Outside NASA, there is the need to make this an international effort.
5. NASA must design with more safety than Mars Direct, and in consequence NASA missions are always heavier than Mars Direct is. NASA missions would require more launches than what I have counted above. This should not be viewed as a criticism of NASA; it's unavoidable. When the Challenger blew up, there was some danger the entire manned spaceflight program would be canceled. If it had been, the Soviets would have scaled back and the Russians (after the fall of the USSR) would have dropped manned spaceflight. If that had happened, we'd be even more frustrated than we are now.
6. Some of this work IS being done at NASA; the Michael Duke et al paper was done by people employed in Houston. It strikes me as the cleverest piece of thinking I've seen, beyond Mars Direct. It's a simple system and uses insitu resource utilization on the moon. That work is still going on.
-- RobS
If you had an ephemeris on your rover's computer giving Phobos rise and set times--and it rises and sets about three times a day--then you could determine where you are, in that when Phobos rose or set you'd have to be in a narrow band running along the Martian surface. You'd need to time sunrise or sunset, or a star, or Deimos, to triangulate your position more exactly.
But the easier solution for navigation would be to place about six GPS (global positioning system) satellites in Mars orbit. By the time people get to Mars, such a system could pinpoint your location with a centimeter or two. It would probably be accurate enough to allow automated driving, where the rover's computer would have an exact terrain map of the route (preferrably one that has already been bulldozed and photographed from a vehicle) and would use GPS to determine exactly where it was on the route. The vehicle would not have to worry about tumbleweeds, deer, or stray children running in front of it, so it probably could trundle on autonomously while the "driver" and passenger watched television or played cards (or did something useful).
--RobS
I've developed my pictures of the Euro-Hab floor designs and can now describe the first and second floors.
The first floor really requires no description because it is identical to the floor plan someone posted a link to a few weeks ago. It has a large lab/work space that includes a medical area, an EVA prep room, and two airlocks. In terms of pie slices, the lab/workspace is about 2/3 of the pie and the EVA prep room 1/3. On either side of the EVA prep room is an airlock for exiting, a total of two. They are circular. The smaller one is probably the size of a phone booth; big enough for one person only. The larger one can probably accommodate two people in suits. The stairs to the second floor are located on one side of the lab/workspace.
The second floor can be described using "pie slices" as follows. Half the pie is a "living room" which includes six comfortable seats that can be pushed together to form a long couch, an oval table to seat six, and six chairs. The other half of the pie is harder to describe. It has a central circular area, but some of the slices open to the living room and not to the central core. Part of the core area serves as a kitchen. Another part is separated off with a wall that makes a rectangular room running all the way to the outer wall. That rectangular room, which opens onto the kitchen, is the bathroom. Almost a third of the half-pie is a "cockpit/shelter" with its door opening onto the living room. Another room--about a sixth of the half-pie--is a "fitness room" and it also opens onto the living room. The remaining space that is not kitchen, bathroom, cockpit, or fitness, is labeled "storage" and opens onto the kitchen with a door near the bathroom door. So we have this:
Top half of the pie: living room
Bottom half of the pie:
Left 1/3: cockpit
Middle half: kitchen in the "core", with bathroom between it and cockpit and storage "below" it, between it and the outer wall
Right 1/6: Fitness room
Like I said, it's hard to describe!
Driving home today, I looked at Adler Planetarium and I think I saw that the Hab was gone. There was still something there, but it was smaller and I finally concluded that it probably was the slice of greenhouse that had been next to the hab. The greenhouse "slice" had been a cylinder about 10-12 feet in diameter, but it was only about four feet long. I guess the hab is now making its journey to Iceland.
-- RobS
I have been thinking more about the problem of the lack of a suitable launch vehicle for human expeditions to Mars. As Robert has noted, developing a booster able to put 50-100 tonnes into low earth orbit is expensive, especially since manned flights to the moon and Mars are the only need for such a vehicle. Is it possible to use existing boosters?
ONE SCENARIO
I think it is. Here is an example of how it would work. I am assuming here a 24 tonnes to LEO (low earth orbit) capability. The space shuttle can put that much in a low orbit of moderate inclination (though NOT to the International Space Station; it?s inclination to the equator is too high). The Proton can put 21 tonnes into a high inclination orbit, so if it were launched from Kourou or Christmas Island it should be able to lift 24 tonnes into a low inclination orbit. The Atlas V and new Delta IV and the big Ariane can put about 18-21 tonnes into similar orbits. Proton may be best, as it costs $85 million per launch; for 24 tonnes, that?s only $3,300 per kilogram. But I don?t know what its availability is.
Michael Duke et al proposed (details are at ?Romance to Reality?) launching 24 tonnes into LEO divided into an 8-tonne solar-electric booster, an 8-tonne ?lunar based vehicle,? and an 8-tonne regolith processing unit. The solar-electric booster would push the other two to the Lagrange point beyond the moon, where the lunar-based vehicle would carry the regolith processing unit to Aitken or possibly to the lunar north pole.
They also note that the model they propose is about one fourth the size necessary for a Mars expedition.
Applied to Mars, one could try this scenario:
Launch 1: 24 tonnes of Hab structure to LEO.
Launch 2: 24 tonnes of part of the ERV to LEO. #1 and #2 dock under remote control.
Launch 3: A 24-tonne Solar Electric Vehicle is lifted to LEO. It docks to the first two and pushes them to Lagrange 1 or 2, which takes six months.
Launch 4: 24 tonnes of other payload (consumables, suits, scientific equipment, etc.).
Launch 5: 24-tonne trans-Mars injection stage (two tonnes of structure and 23 tonnes of liquid oxygen and hydrogen). It docks to #4.
Launch 6: A 24-tonne Solar Electric Vehicle is lifted to LEO. It docks to #4 and #5 and pushes them to Lagrange 1 or 2, which takes six months. The launching of #5 and #6 are the most time sensitive; they have to be separated by a few weeks. Otherwise, the fuel in #5 begins to boil off. Once #5 is docked to #6, the large electrical output of the latter can be used to re-liquefy the fuel in #5.
Launch #7: Four astronauts are launched to LEO in the ERV cabin with a chemical booster able to send them quickly to the Lagrange point. Of the 24 tonnes, 14 tonnes would have to be fuel plus tanks; ten tonnes would be payload. The ERV cabin in Mars Direct has a mass of 11.5 tonnes, plus a 1.8 tonne aeroshell and probably some additional mass in the form of parachutes. But the mass also includes 3.4 tonnes of consumables, most of which could be part of launch # 4 instead, lowering the total mass of the ERV cabin to ten tonnes.
Once #7 arrives at the Lagrange point?preferably a matter of days after #4 and #5 arrive?it docks with the rest of the ERV. We then have 82 tonnes of useful payload at the Lagrange point, plus a booster with 22 tonnes of propellant. The Mars Direct scenario (*Case for Mars,* page 92) figures that two 140-tonne boosters can toss 86.8 tonnes to Mars, so we have achieved almost the same throw weight. Yet we have used seven 24-tonne boosters instead, costing a total of about $600 million (if the $85 million per Proton launch is correct). The Ariane 5 can launch 18 tonnes to LEO for $120 million; the Delta IV heavy, 20.5 tonnes for $140 million. It would probably be best to use several different launch vehicles from several different spaceports so that a disaster at any one would not stop the program. Even at the higher launch costs of the American and European boosters, the total launch cost would be around $1 billion.
I should add parenthetically that if 82 tonnes to the Lagrange point is still not quite enough for the expedition, an eighth launch, bearing an 8-tonne solar electric vehicle and 16 tonnes of cargo, would raise the total of usable payload at the Lagrange point to 98 tonnes, which is quite a bit more than Mars Direct. This would be the ?luxury option? if you want a heavier vehicle bearing a greenhouse, a larger pressurized rover, or whatever.
It is also worth noting that we have also brought to the Lagrange point two very large solar power arrays for the solar-electric vehicles, either one of which could make the cruise to Mars an energy-rich experience, allowing more power-hungry but efficient life support systems, for example.
ASSEMBLY AT LAGRANGE
Once the astronauts arrive at the Lagrange point, they would dock the ERV cabin and aeroshell that bore them to the lower half of the ERV already waiting for them. They would turn around and dock the fully assembled ERV to the cargo module (#4), and shift some of the cargo into the ERV. Then they would pull away and dock the hab (#1) to the cargo module and shift cargo into it. The cargo module?s flimsy structure (1 tonne?) could then be discarded and the ERV docked directly to the Hab. The two loaded vehicles would dock to the trans-Mars injection stage and the latter would fire briefly to send the complex toward Earth. At a few hundred kilometers above the surface, when the complex was moving the fastest, the TMI would fire to push everything to Mars. If the ERV/Hab complex at that point had a mass of 81 tonnes and the TMI stage a dry mass of two tonnes more, its 22 tonnes of fuel could give the complex a delta-vee of 1.06 km/sec; not quite enough for a six month trip to Mars, but probably enough for a seven-month trip.
The ERV and Hab would travel to Mars in tandem, allowing the ERV to serve as an emergency lifeboat if trouble developed on the Hab. One could even run a cable between them and rotate the complex, with each serving as the counterweight to the other for artificial gravity (though under such circumstances, one could not travel from one to the other without stopping the rotation and winding up the cable). As they approached Mars the vehicles would separate and aerobrake separately, then land a few days apart at the same spot. It is conceivable the crew could even split between the two vehicles and land in both, guaranteeing that someone makes it to the surface.
THE LUNAR EXPLORATION VARIANT
There are some obvious variants to this plan worth mentioning. In one, a 24-tonne version of the Hab and a 24-tonne lunar landing vehicle are launched to the Lagrange point by a 24-tonne solar-electric vehicle, then the lunar landing vehicle deposits the hab on the moon. Note that the Mars Direct hab weighs 25.2 tonnes, but that includes 7 tonnes of consumables; a 24-tonne version would have 5.8 tonnes of consumables instead, enough for a lunar exploration crew for quite a long time.
A fourth launch could carry an eight-tonne solar electric vehicle, an eight-tonne lunar lander, and an 8-tonne regolith processing unit able to make 32 tonnes of liquid oxygen and hydrogen a year from lunar ice (this is the Michael Duke proposal). The eight-tonne lunar lander is capable of being refueled on the lunar surface, holding a total of sixteen tonnes, which the regolith processing unit can make (robotically) in six months. Once the lander is fully fueled, it could be launched to the Lagrange point, arriving there with nine tonnes of its original sixteen tonnes of fuel left.
Then a 24-tonne launch from Earth (#5) could lift a ten-tonne cabin (based on the ERV) with four astronauts and a fourteen tonne rocket to LEO. The fourteen tonne stage hurls the ten tonne ERV cabin to the Lagrange point, where it docks to the lunar lander, which uses its nine tonnes of fuel to land it on the moon. While the astronauts explore, the lunar lander is refueled and it can then launch the ERV cabin back on a trajectory that will take it to Earth, where its heat shield brakes it into LEO. Thus, a five-rocket version of the same plan returns people to the moon. This five-rocket version, if done first, could be used to check out the hab and ERV systems.
TO MARS USING LUNAR FUEL
Even better, if a sixth launch carried a second lander and a second regolith processing unit to the moon, when the Mars mission arrived at the Lagrange point it could be ?greeted? by two lunar landers bearing ten tonnes of lunar fuel each. If the landers were docked and used as TMI stages, one could get more payload to Mars with the seven launches necessary to send people to Mars. If techniques for transferring cryogenic fuel between vehicles are developed?perhaps one should say ?when? because the process, while complicated, seems solvable, especially if the two vehicles dock and spin at a very low speed to give them a little bit of gravity?then lunar landers could carry fuel to the Lagrange point and deposit it, and a fuel transport vehicle (basically a big heat shield with tanks) could carry it to low earth orbit. Every six months two lunar vehicles could carry ten tonnes each up to the Lagrange point, deposit nine tonnes each, and use the remaining tonne to return to the moon for more. The eighteen tonnes could be flown to LEO in a four-ton heat-shielded tanker; six tonnes would be needed to push the tanker back to Lagrange for another load. Thus every six months, two regolith processing units and two lunar vehicles could fly twelve tonnes of fuel to LEO. To push 72 tonnes of Mars mission from LEO to the Lagrange point requires about 180 tonnes of fuel. If two regolith processors can move 12 tonnes to LEO every six months, then they can produce 48 tonnes for LEO in two years, and eight regolith processing units can produce 192 tonnes. Thus for four launches of 24 tonnes to LEO (bearing a solar electric vehicle and two regolith processing units each, which are landed on the moon using lunar fuel from the two processors already there), we can fuel a Martian transportation system for many years, and subsequently we would only need three 24-tonne launches (at $85 million each, that?s only $255 million!) to send people to Mars.
Of course, the nuclear reactors being hauled to the moon are pretty expensive, so the fuel produced there is not much cheaper than launching fuel from the earth?s surface. If, instead, astronauts go to the moon regularly and set up solar power arrays on any peaks in perpetual sunlight, nukes would not be necessary and the system would be cheaper than lots of launches from the Earth.
Regarding the question of using up the supplies that also provide radiation shielding, the Hab carries all the supplies for the 6-month flight AND the 18 month stay on Mars, and shielding is only needed on the flight, so there should be plenty. Once they're on Mars, thr Mars atmosphere plus sandbags will serve quite well.
I may have more descriptions to offer of the Euro-hab. Thursday I stopped there and took 24 photographs, which I just developed. I photographed the blueprints of the three-level hab for Iceland and the pictures are nicer and clear. Using them, I'll try to post a description of the other two floors.
-- RobS
*Case for Mars* gives lots of information about making chemicals (methane is an important starting material), bricks, and glass. Mars will be littered with meteoric iron that can be collected by electromagnet; it can be converted into iron carbonyl using heat and carbon monoxide (whicg can be made from carbon dioxide with electricity). Iron carbonyl is a liquid at room temperature and can be poured into molds, then the carbonyl can be baked out pretty easily.
-- RobS
Regarding a few other points:
I am no so sure that the moon is valuable only scientifically. There is an Artemis Society, just as there is a Mars Society. It is the object of the dreams of some people as well. I think it is the object of less dreaming than Mars, but the dreaming is not zero.
(By the way, "dreaming" is not meant to minimize the importance of nonscientific reasons for doing something. Human beings will return to the moon some day, and will go to Mars some day. Those decisions will not be purely scientific; they will be political, social, and popular as well. There is an excellent article on the SpaceToday website comparing Mars novels and movies to westerns, and it underlines the nature and changing forms of the dreams about Mars.)
Regarding equipment left on the moon, some probably can be reused and perhaps should. Some probably should be left alone; some will be utterly unusable. I wonder whether the Apollo 11 site should remain untouched, with no footprints ever placed there, other than those of the first arrivals. It will be a lot of work retriving equipment; it takes a lot of fuel to fly around the moon, and it will be some time before we have the technology for long surface trips. Certainly, let's put that golf ball in a future lunar museum!
Regarding flybys, Zubrin himself has proposed the idea in print; you can read it at the "Romance to Reality" website (which is really incredible; if you haven't looked at it, you should). Phobos landings are also proposed there. One of my first postings to this Board, in the spring, was about the value of such a mission. Russian scientists are keen to do a Phobos mission in a few years and have already tried one (which failed). For some reason, NASA is uninterested.
-- RobS
As Merp quite rightly notes, the environment of Mars and the moon are not the same; just similar. The biggest difference probably is gravity. A -100 Centigrade wind blowing on Mars may be colder than a vacuum above -150 Centigrade regolith. Suits cannot be designed to protect significantly against radiation in either place. But overlaps do exist. Moon vehicles need heatshields if they fly to Earth orbit, as most would. If they only fly on the moon, it is easy enough to remove the heat shield, if it is so designed.
There is a site I mentioned about a week ago where an astronautical society studied three options: moon alone, Mars alone, and both. Both did not cost twice as much as either; it was something like 25-50% cheaper than the two separately.
-- RobS