Looking for Info on Propulsion Concepts using Lunar Mat'ls

[skywalker01]

Since part of our reason for returning to the Moon is to make use of Lunar materials both for going to Mars and to make manned space exploration affordable and sustainable, I was wondering about past work that has been done on propulsion systems that make use of Lunar materials.<br /><br />Obviously if water ice is available at the Lunar poles in quanity then LOX/LH2 rockets will be possible. But what if it isn't, or if the quanities are too small for a sustained program?<br /><br />There is also a limited body of work that has been done on LOX/Alum rocket motors (Isp approx 267 sec), two materials that were found in quanity at all the Apollo landing sites. But with performance that low is this propellant combination suitable for going to Mars?<br /><br />Then there is the idea of bringing up LH2 or some form of hydrocarbon from Earth and using that in combination with Lunar LOX.<br /><br />But what about some of the higher performance options?<br />Is there a material on the Moon besides LH2 or water in the unproven polar ice that would work with a nuclear thermal rocket or a solar thermal rocket?<br /><br />And is there some propellant combination available on the Moon that could have its performance improved via the addition of thermal, electric, or microwave energy that would make it a better choice than LOX/LH2?<br /><br />And then there is the issue of which idea is most cost effective in terms of both performance, and cost to extract and use. <br />Does anyone know of any work that has been done in this area?<br /><br />Thoughts, ideas, and information welcome.

 

[quasar2]

i`ve heard of using Lunar Regolith as fuel. if feasable, this would be easier than refining anything else. if i`m recalling this correctly, Regolith is heated & propelled to the rear of a vehicle. & i`m not sure of the efficiency of this. but certainly there`s alot of it. about the only thing which would worry me about this would be if something were scooped up accidentally. this being an important scientific discovery. so i`d recommend analyzing it first. hope this helps. <div class="Discussion_UserSignature"> </div>

 

[lunatio_gordin]

I believe that's in zubrin's "Entering Space", but i'm not entirely sure. they were baking some gas out of the regolith.

 

[ehs40]

well i bet there is something on the moon that we can use for fuel

 

[spacester]

I wonder if lunar water may turn out to be too precious to fritter away as rocket fuel.<br /><br />I think the propellant for Lunar operations comes from the Asteroids, just one good NEA is all we need. Now most people think that Asteroid mining is in the far future so they prolly think that's crazy talk.<br /><br />I have yet to have anybody show me why an icy NEA isn't the best choice for a Cis-Lunar propellant source and why we can't make that happen right away.<br /><br />Until we get water and propellant from NEAs, it'll mostly come from Earth like most everything else. If we do get water from the lunar poles, IMO it should be for local use and recycled. <br /><br />Ooops, sorry, that wasn't a great answer to your question. LUNOX is totally doable, so you're looking for fuel only . . . and um I once heard about a nuke engine that would use ground up regolith as propellant . . . <div class="Discussion_UserSignature"> </div>

 

[le3119]

We should be able to "bake" the hydrogen out of lunar soil, just as we would do for oxygen. Over four billion years of exposure to the solar wind, the lunar regolith has accumulated considerable amounts of hydrogen ions, which could be a fuel source.<br /><br />Go to: http://dept.physics.upenn.edu/nineplanets/luna.html<br />for a discussion on lunar hydrogen

 

[skywalker01]

Quasar<br /><br />I spent the evening searching my memory and then finally remembered O'Neil's mass driver propulsion system. I am sure there is a web site on it and I will be looking for it.<br />The idea of being able to go to Mars using unrefined Lunar regolith for reaction mass and then get the reaction mass for the return from one of the Martian Moons is very interesting.<br />I suspect the performance of the concept will depend on the amount of power used to accelerate the reaction mass, combined with the mass of the accelerator and the mass of the power system.<br /><br />Thank you for the reminder.

 

[skywalker01]

I think you might be right. If the amount of Lunar water turns out to be too small then the idea of getting water ice from a near Earth asteroid becomes very attractive.<br />And just think what great precursor missions they would make for going to Mars.<br /><br />But my guess is that the 'Mars or Bust' people will not want to wait for that and they will fall back on the LUNOX plan of Earth supplied LH2 if Lunar hydrogen is not available.

 

[skywalker01]

Interesting idea and interesting links.<br />You've given me plenty of interesting reading material and food for thought. At first blush I think it will depend on the level of concentration of the hydrogen ions. If it is as low as the concentration of He3 then it probably won't be economic -- but more to read.<br /><br />Thank you

 

[nexium]

My guess is everything that can be mined on Earth is found in luner/asteroid regolith = soil. The problem is homogenized instead of concentrated into rich ores. If we process a million tons of regolith we will recover a gram or more of almost everything. So we can likely get enough graphite and Uranium to build thermo nucliar motors on the moon, if we process huge quantities of luner regolith. Neil<br /> I agree we should make a human colony on a near Earth asteroid = NEA before we visit either the Moon or Mars. The only disadvantage is a tiny asteroid does not have the PR glamor of going to the Moon or Mars. Neil

 

[frodo1008]

I really don't like to be the spoiler here as you seem to get angry with me when I am. But there is at least one little problem with using Near Earth Objects for mining. Unlike the relativaly slow moving moon, these objects pass through the Earth/moon system at very high velocities. Otherwise they would become moons of the earth themselves. Matching these velocities is going to be very, very difficult for any mining concern. <br /><br />However, if you have legitimate answers to this problem I am all ears! There are indeed some slowly moving asteroids. Unfortunately they are in the asteroid belt which is about half the way between Mars and Jupiter!<br /><br />If we had the space technology and infrastucture to mine in the asteroid belt, we would have long since solved the problem of using the moons materials!