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#1 2003-11-30 23:20:25

RobS
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From: South Bend, IN
Registered: 2002-01-15
Posts: 1,701
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Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]I just discovered a new report on the web about Using Lunar Ice for making LOX/LH2 fuel. The plan is by Brad Blair, Javier Diaz, Michael Duke, and several other people, two at the Jet Propulsion Lab and two at a business planning company. The report proposes a commercial system to mine lunar ice and bring water to LEO (low earth orbit) for the purpose of propelling satellites from there to geosynchronous orbit. They calculate that it is possible to set up such a system and actually make a profit, though it is risky and difficult.

The plan involves placing a 13.8 tonne fuel making unit on the moon, which would include a 3.4 tonne, 100 kilowatt nuclear reactor. The wheeled plant would scoop up lunar regolith, heat it from 60K to 200K, capture the vaporized water, electrolyze some of it, and store the rest. The system assumes regolith is only 1% ice, though it works better if the regolith is 2% ice. They also say the current data suggests the regolith in permanently shaded areas is 1.6% ice, so their system is based on the best information currently available.

A lunar water tanker would carry 23.9 tonnes of water to the L1 lagrange point between the Earth and moon. It would make 4.5 flights per year. From there, there are two options, and they work out to be about the same. In Architecture 1, 3.3 times per year a cargo shuttle aerobrakes 20 tonnes of water to LEO (the other 4 tonnes is used to return the tanker to the lunar surface). In LEO the water is converted into LH2 and LOX. Three times a year an OTV (orbital transfer vehicle) would stop by, pick up 11.3 tonnes of propellant, carry a 5 tonne satellite to geostationary orbit, and return to LEO. The excess water would be used to return the L1 shuttle back to L1. There would also be excess oxygen produced at all the steps because water is 8:1 oxygen to hydrogen, but optimal performance is achieved by engines using 6.5:1 oxygen to hydrogen. Such engines require burning extra hydrogen, which means oxygen is "thrown away" (though it could be breathed or otherwise sold).

Architecture 2 eliminates the LEO refueling station. OTVs refuel at L1, aerobrake to LEO with their fuel load, dock with a satellite, boost it to GEO, then return to L1 to refuel. Advantages of this system: fewer vehicles to develop and fly; if you want to launch satellites into orbits other than equatorial, L1 is more flexible (because the LEO refueling station would be in an equatorial orbit).

The development cost of the entire system is estimated to be about 7 billion bucks, $5 billion being for the lunar propellant plant. The L1 and LEO refueling plants would be small and not very expensive. Profit is possible over ten years if one makes a lot of assumptions; one must ultimately capture the business of lifting 30 satellites to GEO per year, at a cost of $25,000 per kilogram each (at 5 tonnes each satellite, this is $125 million per satellite of income). It is assumed it will already cost $10,000 per kilogram to get them to LEO. Only 1 lunar plant is needed. The vehicles are able to fly once a month for a total of 120 flights before replacement (which is a lot!).

The report notes that this system would be an immense help for manned flights to the moon and Mars because it would lower the costs of fuel. At $10,000 per kg to LEO, it costs $90,000/kg to land stuff on the moon when the fuel is hauled from Earth. The cost to Mars is not stated, but should be similar. This system would lower the cost for transMars injection to about $20,000/kg from LEO and probably to about $40,000/kg to the Martian surface.

It occurs to me that if a 13 tonne system can be developed for extracting water from 1% lunar regolith, a system of similar mass (though different design) should be able to extract water from Martian regolith as well. The Martian regolith is several percent water, though higher temperatures might be needed to liberate it (except in the polar regions, of course). This might eliminate the need to fly hydrogen to Mars, which could save quite a bit of mass. It would also mean an outpost would have all the water it needs for plants, oxygen, showers, etc. This could be immensely valuable. Each plant costs $916 million to produce; 2 of them could be very useful. A similar plant on Phobos or Deimos could produce fuel there as well.

I'll try to give a more detailed summary in another few days, after I can print out and read the entire 78 page report.

         -- RobS[/color:post_uid0]

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#2 2003-12-01 12:39:53

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]Hmmmm when I read this idea while pretending to be a commertial space insurance agent, my first thought is "Eeeek!"

But, for a government-funded mission which is not bound on pain of death to all-important profit, somthing like this makes sense for a sustained presence on the Moon and the potential to make trips to the rest of the inner solar system much easier, or at the very least be able to launch larger ships & probes if they can be launched dry from Earth.

I still would like to see an operation on a larger scale though... 25 ton payload LBV, a stationary water cracking plant with multiple 100KWe reactors that makes fuel fed Lunar soil by robot diggers, perhaps ferrying the soil to the plant on "roads" made of glass, which is easy to make on the Moon just by irradiating the soil with microwaves. Could the roads also have imbeded wires to power the Lunar dump trucks via induction?

Anyway, getting water on the Moon would be almost a nessesity for a large Moon base, though I guess it is possible to ferry up enough LH to suffice. Still, it would reduce how much trouble it would be to live on the Moon or Mars greatly. The same for Mars, hauling water to Mars with any expedition weighs alot I imagine, and you could ditch the hydrogen handing equipment too, especially nice since LH boils at a far lower temp than LOX or liquid Methane.

Nasa ought to make it a top priority to develop a mass-production 100KWe rector and to hurry up with their HiPEP "mega ion engine" with ferrying large (25 ton) payloads from LEO to Lunar orbit or L1 in mind. Hopefully this ion transfer vehicle could make the trip with less fuel?[/color:post_uid0]


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#3 2003-12-01 12:56:22

clark
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Registered: 2001-09-20
Posts: 6,275

Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]I posted this bit of rumor in my moonbase thread in the free chat section:

http://www.spaceref.com/news/viewnews.html?id=902

Frank Sietzen, Jr.
Sunday, November 30, 2003

Bush to Charge NASA with Implementing Broad Space Vision to Dominate Cislunar Space

WASHINGTON - President George W. Bush will propose a sweeping new vision of U.S. space leadership that will call for use of the Moon for technology development and partnerships between NASA and the Defense Department to make maximum use of existing or planned U.S. space systems, this column has learned from informed sources.

NASA administrator Sean O'Keefe will be tasked with leading the effort, aimed at presenting Vice President Dick Cheney and the president with a roadmap to what some are calling "renewed U.S. space dominance" during 2004.

Following a year-long review of U.S. space objectives, programs, and assets, the Bush administration was presented with a broad set of options during the summer's deliberations, a source indicated.
[/quote:post_uid0]

interesting, no?  big_smile[/color:post_uid0]

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#4 2003-12-01 14:28:34

Tyr
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Registered: 2002-09-14
Posts: 83

Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]I 've always liked the simplicity of water/NTR  Here's a great site: http://www.neofuel.com  Water presents no boil off problem.  It can be stored in a plastic bladder rather than a heavy fuel tank and this makes very high mass ratios possible, so high that water actually gives better performance than LH2 does despite the lower ISP.  Using water straight in a NTR elimates the need for electrolysis and cryogenic equipment and associated power supplies.  Less mass, less cost, simplicity=reliability The only problem is getting around those who will forbid the launching of anything nuclear.  I've tried to say for a long time that if a nuclear reactor crashed on land it would bury itself in a crater under 30 feet of dirt and anybody close enough to be exposed to radiation will be close enough to be killed by the impact, so why worry??  If we don't use nuclear power to get a foot hold in space and tap energy in the form of 3he and SPS or LPS, we will be forced to use nuclear power on EArth longer and that will entail more risk.[/color:post_uid0]

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#5 2003-12-01 14:32:30

Tyr
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Registered: 2002-09-14
Posts: 83

Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]don't miss this page   http://www.neofuel.com/space98/[/color:post_uid0]

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#6 2003-12-01 21:39:11

GCNRevenger
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From: Earth
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Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]I'm still convinced that chemical ISPP and the use of LOX/LH for Lunar travel and perhaps LOX/Methane or LH on Mars is preferred. Nasa's even got a itty bitty ISPP + model rocket motor to test on Mars I think... Such a device need not be very complex; only electric solenoid gas valves, rotary motion compressors, and mechanical switches asside from the reactor... the big issue I think would be how to keep the reactor cool; maybe suppliment rollable sheets of radiators with intentional boiloff of excess LOX?

The major showstopper achillies heel of using Lunar water as reaction mass in a NTR engine though is how to get enough water to use it straight as reaction mass for these massive "water bag" orbital transfer vehicles... it will be trouble enough to make fuel to operate an LBV and a manned Moon/LEO shuttle. I am also concerned about the water freezing; keeping it warm inside a big bag might be problematic, even if using a reactor waste heat. Hydrogen bubbles could at least be centrally collected and condenced. Also keep in mind that a nuclear engine doesn't have [b:post_uid0]unlimited[/b:post_uid0] fuel, a very-long-burn NTR will nessesarrily have to operate at lower temperatures to preserve fuel payload of a reasonable mass that can be launched from Earth.

Another big issue is getting water [b:post_uid0]off[/b:post_uid0] the moon "en masse," so to speak. The water-fueled NTR engine won't be enough to get off the ground with any substantial payload without operating at hydrogen-fuel temperature levels, which will cut the engine's life short. The source page at Neofuels suggests a operating temperature of only 1100C, a far cry from the 3000C needed to reach par with chemical fuel. Even if this temperature is reached, having to ground-launch lugging the weight of a nuclear reactor would take a bite out of payload mass I think: the production Nerva engine weighed around 11 tons for 75,000lbs which would be cutting it a little too close for comfort with sub-500sec Isp water fuel. The RS-24 SSME on Shuttle, the best and biggest reuseable chemical engine ever makes about half a million pounds, but weigh around 3.5 tons each. The RL-10 varient on the DC-X (which I think would make a dandy rocket to base LBV on) make 15,000lbs of thrust, yet only weigh 300lbs each... As with any rocket, you have to get out of the gravity well fast!

The LBV must be lightweight, yet even then, it will not haul anywhere near enough water to fill a "steam bag" rocket, and even with the high-nuclear-burnup ~400-500sec Isp possible, is not competitive with LOX/LH chemical engines due to their light weight and no need for radiation shielding. A chemical engine might actually last longer! Hydrogen tankage, the cheif cited advantage of water+NTR, also need not be all that sturdy since it won't be launched from Earth loaded. Shuttle's main hydrogen tank, which I think is a fuel-to-tank weight goal to aim for with (solid like DC-X, not honeycomb like X-33) composit instead of Al/Li alloy, lugs about eight pounds of hydrogen per pound of tank.[/color:post_uid0]


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#7 2003-12-02 10:15:23

Tyr
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Registered: 2002-09-14
Posts: 83

Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]However, the Moon's gravity is low enough for Anthony's rocket to work, even at a low ISP.   It won't be hard to mine up the ice if it exists at suspected concentrations, and it will be much easier to tap plain water than hydrogen which would also require ice mining.  I feel that a higher ISP for the Steam/NTR is desirable for the sake of efficiency.  This might demand a rocket motor with a longer lifetime, but I am sure one is possible.  A chemical rocket motor might be more light wieght, but the added mass of electrolysis cells, refrigeration equipment, heavy insulated storage tanks, powerplants to run all this and assorted hardware is not worth it when simple water/NTR can be used.[/color:post_uid0]

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#8 2003-12-02 10:21:37

Tyr
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Registered: 2002-09-14
Posts: 83

Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]Also, the Shuttle's fuel tank can only keep LH2 cold for hours, not days or weeks as would be necessary with a spaceship or fuel storage depot.  LH2 is very difficult stuff.  TAnks have to be pre-cooled before LH2 is pumped into them or it will flash into gaseous hydrogen.  Some LH2 is sprayed into the tank to cool it and the gasified hydrogen is collected and reliquified, thereby complicating and adding expense to the whole thing. Then the LH2 is pumped in.  Special plumbing and fitting are required.  Simple plastic hoses will work with water.  I say- SAY NO TO LH2 WHENEVER YOU CAN.[/color:post_uid0]

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#9 2003-12-02 16:13:44

GCNRevenger
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Posts: 6,056

Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]Although hydrogen tankage would be bigger than a water tank, it need not be that heavy. Keep in mind that the Shuttle main tank must be insulated against [i:post_uid0]Floridian air[/i:post_uid0], not the vacuum of space. The only heat sources in space I can think of are from the ship, which could be isolated with spacers at the attach points, and the sunlight which could be reflected with a mylar-style shiney skin. Also keep in mind that a space rated hydrogen tank does not have to hold a 100 ton airplane or resist the torque of several million pounds of rocket thrust... only enough to resist its loaded weight at launch and air resistance. It need not even be made of metal, it could be made of solid composit DC-X style.

Furthermore, I suspect running "simple" heating lines from the NTR or NEP reactor to keep water warm will be a bigger issue than it may first seem, with all the fragile plumbing - which must be launch hardend - and having to run coolant lines into your source of power and thrust. Having a centrally located hydrogen condenser would at least be easier to integrate.

About Mr. Anthony's water truck, I think it assumes an almost comedic amount of reliability... three flights a day... that would lead to its destruction rapidly. Also, I think that his estimate of reactor mass is somewhat, well, optimistic and that he has neglected to take into account that a reactor with that level of fuel burnup efficency is hard or impossible to create.

Lastly, on the Moon you could simply put the LH tanks in the shadows of craters and ridges and suspend them off the ground with pointed low-conductance "feet" to eliminate much of the headache of keeping the stuff cool, which ought not be a problem anyway with a hydrogen condenser powerd by a nuclear reactor and a plentiful supply of LOX for coolant. I wonder if a sealed glass blanket filled with oxygen would make good indigenous insulation.[/color:post_uid0]


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#10 2003-12-02 16:33:17

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]And if IR energy from the Moon itself is a problem, either surround the tanks & lines with "walls" made with IR-reflecting substances or cover the tanks themselves with them. Gold or metal vapor deposited on plastic sheeting would be extremely light and offer good protection on the order of 99% reflectance.

Oh, and guess which fuel will [b:post_uid0]NOT[/b:post_uid0] work in a GCNR or VaSIMR engine?[/color:post_uid0]


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#11 2003-12-02 18:40:47

Tyr
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Registered: 2002-09-14
Posts: 83

Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]Furthermore, I suspect running a hydrogen condensor powered by the NTR or NEP reactor to keep LH2 cold will be a bigger issue than it may first seem, with all the fragile plumbing - which must be launch hardend - and having to run turbine working fluid lines into your source of power and thrust. Having a centrally located heat pipe system would at least be easier to integrate. And heat pipes have no moving parts, unlike a hydrogen condensor with its compressor, turbine, and radiator powered by the reactor.[/color:post_uid0]

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#12 2003-12-02 18:44:02

Tyr
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Registered: 2002-09-14
Posts: 83

Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]The Mark-Maxwell tanker, using a simple Kevlar bladder and a NTR.  http://www.neofuel.com/markmaxwell/maxw … tanker.jpg[/color:post_uid0]

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#13 2003-12-02 20:45:35

GCNRevenger
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Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]Even if the outlandish reliability requirements could be met on this "non user serviceable" nuclear rocket, there is no lake of ice to load it with. I think the any early base will be doing quite well to harvest two or three hundred tons of water a year. Clearly insufficent to power the water truck and give it enough fuel to lift to the transfer stage to compete with LH.

The rocket cannot be serviced because of its NTR engine, which produces substantial radiation even when shut down (after its initial startup), and would be deadly to aproach for weeks, if not months at least while the short-lived nuclides decayed. Shielding is too heavy, and a chemical engine need not carry a reactor or shielding.

The hydrogen condenser will not be a large device because it will not have to liquify much hydrogen, given a reasonably low boil off rate achieved through thermal isolation and solar shielding. It will not have lengthy plumbing, because it will be mounted near the reactor which powers it which is naturally near the fuel tanks in an NTR system, nor will it need the pipes to run far in/around the fuel tank. I propose that the compressor could be connected to the same turbine shaft that will provide electrical power to the engine, but electrical supply should not be an issue with a nuclear reactor if this is impractical.

A heat pipe system would require some plumbing to distribute the heat to the rather large water bag to prevent freezing if required which will be connected to a reactor coolant line, which reduces the modular construction of the reactor and simply makes me nervous. This plumbing must be able to survive Earth launch at 3-4G and the earthquake of launch vibration.[/color:post_uid0]


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#14 2003-12-03 01:57:59

RobS
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From: South Bend, IN
Registered: 2002-01-15
Posts: 1,701
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Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]The other significant limitation to keep in mind is cost. The plan I was reading indicated that the robotic system would cost $7 billion to design and set up, which included $1 billion to design and build one nuclear reactor for surface power. The chemically fueled transportation system cost less than a billion to design and build; $4 billion was to design the rest of the robotic mining unit and acquire the information about the moon needed to design it. Adding a nuclear steam rocket in the place of the chemically fueled tanker vehicles adds at least a billion dollars to the costs, probably more; furthermore, because it uses water much less efficiently because of the lower Isp, you may need to add a second $900 million robotic ice mining unit with a second reactor. The $7 billion plan was profitable only if the water could be sold as hydrogen/oxygen fuel in low earth orbit for about $10,000 per kilogram, and in a large quantity (about 500 tonnes per year). It is hard to make that system competitive against Russian rockets. One could always assume that the government might step in and build all or part of the system as an investment in the future; but why should taxpayer dollars be wasted building a system to import water from the moon more expensively than a system using Russian rockets? Adding the uncertainty of the cost estimates and demand estimates, and you see how dicey the entire plan is. Replacing the surface nuclear reactor with solar power, the report says, makes the costs less and makes the system more competitive, but adds the complication that solar power has to be imported from mountain peaks in near-perpetual sunlight into permanent shadow. If the cost of launching stuff into low earth orbit decreases significantly--and let's hope it does!--it makes the cost of launching the lunar ice making system less, but decreases its overall profitability even more.

The main advantage of the system is derived from adding a few pieces the report does not detail: sending humans back to the moon and eventually to Mars. These activities require a lot of fuel and make the fuel-making system more profitable.

If I get the chance, in the next few days I'll add more information from the "business" side of the report. It's amazing how much taxes, insurance, and interest payments add to the overall costs, for example; they assumed that the tax rate on the profits would be 40%! I would have never assumed something like that!

       -- RobS[/color:post_uid0]

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#15 2003-12-03 11:01:13

GCNRevenger
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Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]Although the idea sounds nice in theory, I have strong doubts about the economics when faced with cheap Russian, Indian, and Chinese satelite launchers. In order for America to regain marketshare, a Lunar fuel operation is not the answer, but rather to develop reuseable launchers. The only way to compete with inexpensive Russian/Indian/etc labor and hardware is to not have to throw the more expensive American hardware away. The RS-84 engine should be rushed to prototype stage and design work should begin for a small single-engine LOX/RP1 flyback booster able to mate in pairs or trios with a variety of ELVs for heavy loads or directly to ELV second stages for smaller ones in single or paired configuration.

Another possible means to save on getting sats up to GEO, is for Nasa to hurry up and build their ion powerd tug that was shelved long ago. No more waiting, heel dragging, or "technology development"! If solar pannels will work, use solar pannels, if a reactor would work better then put more effort into Prometheous. Hauling a small tank of ion engine fuel and a docking beacon would surely be better than having to bring a 3rd stage booster or useing a bigger LV.

This same tug could perhaps be scaled up, with the use of nuclear power if nessesarry, to support cargo transfers to the Moon for our seemingly impending return.

Frankly, considering that the water on the Moon is not all that easily accessable, where harvesting a few hundred tons a year will be "a big deal," then mining the fuel only makes sense for returning rockets to and from the Earth or for fueling ships heading outide of Lunar orbit. If the manned Lunar transfer shuttle is going to only have 4-6 seats, I think plans ought to be made for 3-6 flights a year from Earth to the Moon and back.[/color:post_uid0]


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#16 2003-12-03 17:58:40

RobS
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From: South Bend, IN
Registered: 2002-01-15
Posts: 1,701
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Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]I largely agree with you. It is interesting to note the report does not mention ion propulsion at all. There is already a commercial plan to build an ion tug that would be launched on each Ariane; it would go up to GEO, latch onto existing satellites there, deorbit them, or provide station keeping when their supply of fuel is exhausted, or bring them to LEO for refurbishment. I don't think a lunar water system can compete with that.

      -- RobS[/color:post_uid0]

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#17 2003-12-04 21:38:54

GCNRevenger
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Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]Nasa's work on really big ion engines paired with Prometheous is starting to look pretty attractive for sending large payloads to the Moon or for small payload orbit change.

http://www.spacedaily.com/news/nuclearspace-03q.html

Four of these engines, or a pair of their larger siblings, paired to a 100KWe reactor (the first product of Prometheous probobly), would be great for pushing satelites from LEO to GEO and back. For sending payloads and fuel to the Moon, build a bigger tug with a 400KWe reactor, a LH/LOX condenser, and clusters of theses or their larger siblings... I am especially interested in their fuel efficency; double that of previous engines?

Hows about this for a slow ramp-up to a Lunar base? A twist on the Drake plan, optimised to start putting hardware and people on the Moon without signifigant orbital infrastructure but with the capacity for larger loads later when a Moon base is built while retaining the ability to land small payloads anywhere on the Moon likewise without orbital infrastructure.

-Lift body OSP is built to ferry six to and from orbit cheap and 5-ton expendable AAS tug built to get small to medium (20 ton) cargoes from an EELV to the ISS or a cargo LBV. In the waning days or following ISS, OSP will be used as the crew taxi to Lunar Shuttles.

-Dedicated manned Lunar Shuttle built that can make the trip from LEO to the Moon and back to LEO without refueling with six passengers, and preferably without staging. Return stage must be LOX/LH powerd, and light enough to fly on an EELV HLV dry with transfer stage and would not be launched manned unless an emergency OSP flight could be sent to retrieve a stranded crew.

-Dedicated cargo LBV built able to carry small (8 ton) payloads from Lunar orbit to the Lunar surface and back without refueling or staging and be light enough to fly to LEO dry but with payload on a EELV HLV. Also must be LOX/LH powerd and capable of performing docking maneuvers.

-Heavy nuclear ion tug built for orbital transfer, must be able to reach LEO dry on one EELV HLV or wet on two, carry a loaded small cargo LBV to Lunar orbit and back to LEO (empty) without refueling and must carry a small fuel condenser if the long flight will cause signifigant boiloff of any ferried LOX/LH fuel. Since all cargoes would be brought to it by LBV or AAS tug flights, it does not require fine velocity control or self-docking capability

-Launch an orbital platform into LEO if nessesarry early on to serve as a fuel depot. Just a solar powerd truss with a fuel condenser and docking beacons, perhaps some fuel tanks, must also be EELV HLV capable dry.

-Also, build a reuseable AAS-derrived LEO orbital tug, LOX/LH fueled and stationed at the fuel depot, capable of capturing large payloads from EELV HLV launch and bring them to the ion tug or the fuel depot rapidly. Since future EELV HLV or equivelent rockets won't need to carry an expendable AAS tug, they could instead carry extra ion tug fuel, eliminating the need for seperate ion tug fuel launches.

-When Lunar LOX/LH becomes practical to extract, fuel is launched by the cargo LBV to Lunar orbit to a similar unmanned orbital depot flown from LEO by the ion tug. From then on, the ion tug will mated by an AAS tug in LEO with 20 ton cargo modules that have ~5 tons of ion fuel for the round trip, staying under the 25 ton EELV limit. Then its on to Lunar orbit to hand off the cargo to an LBV stationed and refueled in Lunar orbit, and then down the Moon. The ion tug would haul a Lunar fuel tank back to Earth, mated by a second AAS tug stationed in Lunar orbit, to power manned Lunar Shuttles parked in LEO.

After that, just add more ships and Lunar fuel plants to the system as needed, and build a real base (i.e., with more than one Lunar shuttle worth of fuel.)[/color:post_uid0]


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#18 2003-12-04 21:48:57

GCNRevenger
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From: Earth
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Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]Oh yeah, and once fuel is available on the Moon reliably, the Lunar Shuttles would be sent with no staging to the Lunar surface, refueled there, and return to LEO.[/color:post_uid0]


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#19 2003-12-04 22:04:30

GCNRevenger
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Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]Further, the LBV cargo lander would not initially have to reach Lunar orbit with any payload until Lunar fuel were produced in quantity, only getting itself back to the ion tug.[/color:post_uid0]


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#20 2003-12-05 01:28:26

RobS
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From: South Bend, IN
Registered: 2002-01-15
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Re: The Moon as Fuel Source - New plan for making fuel at Moon's poles

[color=#000000:post_uid0]It may be a few days before I can read this carefully; I have to give a weekend course in a few hours. But yes, I think this is the basic idea of the Duke plan, of the NExT people (NASA Exploration Team) and some others. Have you looked at my Mars 24 plan? It's basically an extension of the same plan to Mars. The two Mars Direct vehicles are very close to 25 tonnes; the ERV is 28 tonnes, and that includes a few tonnes of consumables that could be flown up separately later. So the two Mars Direct vehicles could be launched via EELVs (though they would have to be redesigned to fit the smaller fairings, and I think a bigger six-meter fairing would be a wise addition to the EELVs for the Mars project). A third EELV with xenon fuel could see the vehicles safely to lagrange 1, where a lunar-based vehicle with lunar fuel would push them back to Earth, then on to Mars. My plan is a bit more complicated than this because I incorporated a few other changes; an interplanetary hab based on Robert Dyck's suggestion; and a reusable Mars shuttle in place of the ERV. But the basic idea was the same.

Of course, a heavy-lift vehicle would be better. But who knows whether we will ever see one built. EELVs may be endangered species if ion engines improve the efficiency of launches to GEO, because 10 tonnes to LEO may be enough instead of 24 tonnes for commercial launches.

        -- RobS[/color:post_uid0]

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