Author Topic: Making a Lunar Ascent rocket fuel on the Moon  (Read 8787 times)

Offline A_M_Swallow

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Making a Lunar Ascent rocket fuel on the Moon
« on: 08/18/2007 12:52 AM »
Lunar Ascent stages that use fuels made from materials available on the Moon can produce major cost savings at the 1 lunar launch a month needed by a Moon Base containing 24 people.  Current rocket fuels are based on materials easily available on the Earth like hydrogen from water.

Two elements that the Moon has only tiny amounts of are carbon and hydrogen, so a Moon Base should avoid using them (except for food).  Rocket fuels that require carbon and hydrogen will have to be brought from the Earth and are on the wrong end of too many Delta_Vs.  

Can we devise a rocket fuel that can be made from the materials on the Moon's surface?
There are two main burns:
a.  Lunar surface to Lunar Orbit (and possibly the lunar landing).  This will require a chemical rocket.
b.  Lunar orbit to Earth Orbit (and possibly Earth Orbit to Moon Orbit).  This could be chemical or solar electric.

Moon's gravity = 1.622 m/s/s
Lunar escape velocity = 2.38 km/s
Moon to lunar orbit = 1.6 km/s
Lunar orbit to LEO = 4.1 km/s
http://en.wikipedia.org/wiki/Delta_V


Materials available on the Moon's surface:
Oxygen
Silicon
Iron
Calcium
Aluminium
Magnesium
http://en.wikipedia.org/wiki/Lunar_soil


Looking at the list of materials a hybrid engine that burns aluminium dust and liquid oxygen may be a possibility for Lunar Ascent journeys although there may be a better mixture.

There is no obvious element or compound for an ion thruster.

Andrew Swallow

Offline meiza

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Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #1 on: 08/18/2007 01:04 AM »
How about a monopropellant gel of aluminium dust in liquid oxygen? :)
*ducks*

Offline A_M_Swallow

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Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #2 on: 08/18/2007 01:20 AM »
Quote
meiza - 18/8/2007  2:04 AM

How about a monopropellant gel of aluminium dust in liquid oxygen? :)
*ducks*

That sounds like a good explosive if a little unstable.

Offline sfxtd

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Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #3 on: 08/18/2007 01:48 AM »
Monopropellant is probably not practical, but a LOX hybrid rocket might be possible using the metals for fuel and other elements for binders and fillers. It would really mess up the neighborhood spewing all of those oxides around the launch area.

As for other resources, I was wondering how much solar wind might be a source for useful elements and found this brief http://www.lpi.usra.edu/meetings/moon99/pdf/8040.pdf. it is interesting, but I do not know how it will relate to practicality.

Offline CuddlyRocket

Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #4 on: 08/18/2007 07:34 AM »
An aluminium/LOX monopropellant rocket has apparently already been successfully tested under a NASA contract, albeit on a small scale.

Offline A_M_Swallow

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Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #5 on: 08/18/2007 10:50 AM »
Quote
CuddlyRocket - 18/8/2007  8:34 AM

An aluminium/LOX monopropellant rocket has apparently already been successfully tested under a NASA contract, albeit on a small scale.

It sounds like the Lunar Lander Centennial Challenge could do with a third category in 2008 for a craft using a "Moon Manufacturable Fuel".  An extra $1 million in prise money could save a fortune down the road.
http://www.xprize.org/challenges/lunarlander/2007

Offline Jim

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Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #6 on: 08/18/2007 12:50 PM »
Quote
A_M_Swallow - 18/8/2007  6:50 AM

Quote
CuddlyRocket - 18/8/2007  8:34 AM

An aluminium/LOX monopropellant rocket has apparently already been successfully tested under a NASA contract, albeit on a small scale.

It sounds like the Lunar Lander Centennial Challenge could do with a third category in 2008 for a craft using a "Moon Manufacturable Fuel".  An extra $1 million in prise money could save a fortune down the road.
http://www.xprize.org/challenges/lunarlander/2007

Way too early for such a challenge.  There are no near term applications.   A 24 person moon base isn't going to happen in our lifetimes

Offline coach

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Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #7 on: 08/18/2007 03:30 PM »
"A 24 person moon base isn't going to happen in our lifetimes"

Jim, I'm holding you to this.  I'm 36 years old and the average lifespan of a human continues to grow.  I could easily live to 90.  A 24 person lunar base is more than possible in the next 50 - 60 years.  


Coach

Offline Tom Ligon

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Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #8 on: 08/21/2007 03:55 PM »
Yup, Coach, it is just a matter of will and money.  We'll do it if we really want to enough.

Landing is another question, but launching from the Moon with some form of catapult, not necessarily capable of reaching full orbital velocity, is a question for some fun calculation.  The idea here is to launch on a suborbital trajectory and then kick in an ion or arcjet propulsion system.  See if you can add enough delta V to make orbit before hitting the ground ... er, regiolith.

Ion propulsion systems currently make WAY too little thrust to make this viable.  Arcjets might be closer.  Either way, the power levels per kg of launch mass will have to be vastly higher than they are now.  

So here is the thought.  Is some other means of chemical energy storage than "combustion" a possibility?  Could the available elements be so combined as to produce sufficient electrical energy to power a hellish arcjet, which would, in turn, be used to spew the waste reactants out the backside?

My instinct tells me this is probably a fool's errand, a bit like using a fuel cell to make electricity to run a steam arcjet.  But the cost of the gedanken experiment, here on this forum, is pretty reasonable.

Offline Tom Ligon

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Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #9 on: 08/21/2007 04:02 PM »
Landing:  how shallow an orbital approach could one make to the surface?  

I realize this approch is fraught with problems, including the above-mentioned lunar dust abrasion mess (nobody mentioned its toxicity, either).  

Choosing some big, flat basin with no major peaks in the way, one could conceivably establish a very low orbit, possibly 10 miles or a little less, prior to landing, then do a very slight de-orbit burn that just grazes the surface at that basin.  The vertical component of the impact must be very gentle in order to maintain control and not injure the passengers.  The path must be clear of rocks, and consist of groomed dust or other surface that allows the craft to make a long skid to slow down.  What is lunar orbital velocity?  This would be another e-ticket ride!  

But relatively low-tech.

Big business after the landing in replacing the skids and selling the crew clean underwear.

Offline kraisee

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Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #10 on: 08/22/2007 08:47 PM »
Quote
A_M_Swallow - 18/8/2007  6:50 AM

It sounds like the Lunar Lander Centennial Challenge could do with a third category in 2008 for a craft using a "Moon Manufacturable Fuel".  An extra $1 million in prise money could save a fortune down the road.
http://www.xprize.org/challenges/lunarlander/2007

That sounds like a damn good idea to me.   How could we get such a suggestion considered for future challenges?

Ross.
"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

Offline wannamoonbase

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Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #11 on: 08/22/2007 09:40 PM »
Quote
kraisee - 22/8/2007  4:47 PM

Quote
A_M_Swallow - 18/8/2007  6:50 AM

It sounds like the Lunar Lander Centennial Challenge could do with a third category in 2008 for a craft using a "Moon Manufacturable Fuel".  An extra $1 million in prise money could save a fortune down the road.
http://www.xprize.org/challenges/lunarlander/2007

That sounds like a damn good idea to me.   How could we get such a suggestion considered for future challenges?

Ross.

I agree it sounds like a good idea and less far fetched than an elevator, which currently sounds like it contributes about as much real knowledge as those middle school toothpick bridge challenges.  Figuring out how to make LOx from lunar soil is far more beneficial.  I wouldn't even mind taking the LH2 if you can get the LOx its more of the weight.  

If you can get the fuel and oxidizer on the surface then you are really in business.  How much smaller is the descent stage if you don't have to take the ascent fuel?  

Could you have a single ascent/decent stage if you could just refuel it on the surface?  

What would be the weights savings there?
SpaceX, just a few things planned for 2018: FH, Starlink Prototypes, Block 5, Dragon 2, Increased launch rate.

Offline BarryKirk

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Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #12 on: 08/22/2007 09:47 PM »
Would that be a skid or a skid, bounce, skid, bounce.  Like skipping a stone on a pond...

Sadly that would really draw out the decel distance.

Unless the surface was a graduall uphill run.

Better to use a maglev rail system.

Offline A_M_Swallow

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Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #13 on: 08/22/2007 10:32 PM »
Quote
wannamoonbase - 22/8/2007  10:40 PM
{snip}
If you can get the fuel and oxidizer on the surface then you are really in business.  How much smaller is the descent stage if you don't have to take the ascent fuel?  

Could you have a single ascent/decent stage if you could just refuel it on the surface?  

What would be the weights savings there?

The answer to these questions changes depending on whether the Lunar Lander is reusable or use once and throw away.

If use once and throw away fuelling the Ascent Stage on the Moon will save a few tons.

Reuseable Lunar Lander.  Since
   refuel at L2, L2 to Moon, Moon to L2
and
   L2 to Moon, refuel on Moon, Moon to L2
have the same Delta_V there is probably not not much saving of mass.

The saving is that refuelling at L2 is using fuel brought from Earth.  This requires extra fuel Earth to LEO, LEO to L2 plus the throw away Ares V and EDS rockets.  The cost of the extra $1 billion Ares V rocket per Moon take off soon adds up.


Offline Tom Ligon

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Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #14 on: 08/23/2007 06:12 PM »
BarryKirk,

Yeah, I want to be sure the bounce-skip thing can be controlled or eliminated. The dynamics would be tricky.

If you touch down just before perigee, on skids with shock absorbers, there would be very little vertical velocity.  The surface would have to be soft, probably groomed dust, deep enough that the skids dig in and start to scrub off kinetic energy fairly quickly.  Turning uphill after perigee would tend to keep the thing in contact and maximize deceleration.

I picture this as a temporary measure that could bring down payloads (such as that LH2 needed for launch in a proposal above) with minimal use of resources.  Expended skids can be made up with lunar materials.  

Some form of magnetic capture is obviously more elegant long-term, but you need a presence on the Moon to be able to establish it.  In some basins, this trick might take only some bulldozer work.  It will, however, require frequent maintenance.  I image the dust would be sent flying for huge distances.

Early on, with more cargo coming down than going up, this might be a possibility for construction materials.  High mass, not life-critical, and rugged payload.

Offline A_M_Swallow

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Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #15 on: 08/23/2007 06:33 PM »
Quote
Tom Ligon - 23/8/2007  7:12 PM
{snip}Some form of magnetic capture is obviously more elegant long-term, but you need a presence on the Moon to be able to establish it.  In some basins, this trick might take only some bulldozer work.  It will, however, require frequent maintenance.  I image the dust would be sent flying for huge distances.

Early on, with more cargo coming down than going up, this might be a possibility for construction materials.  High mass, not life-critical, and rugged payload.

Even using radio controlled bulldozers a dirt runway will need someone to establish it.

For a magnetic landing, put the magnets on the spaceship.  Can you use a metal and glass fibre cable strung between two mountains as your runway?

Offline A_M_Swallow

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Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #16 on: 08/23/2007 07:09 PM »
Quote
kraisee - 22/8/2007  9:47 PM

Quote
A_M_Swallow - 18/8/2007  6:50 AM

It sounds like the Lunar Lander Centennial Challenge could do with a third category in 2008 for a craft using a "Moon Manufacturable Fuel".  An extra $1 million in prise money could save a fortune down the road.
http://www.xprize.org/challenges/lunarlander/2007

That sounds like a damn good idea to me.   How could we get such a suggestion considered for future challenges?

Ross.
This Lunar Lander game appears to be a competition won by the ship that does not crash.
http://space.newscientist.com/article/dn12109


The official way of sending a suggestion to the Centennial Challenge is to send an email to the address on this NASA webpage.
http://centennialchallenges.nasa.gov/cc_submit.htm

However getting someone to read the email is a different matter,  Advance internal notification from someone important appears to work in most organisations.

Offline simonbp

Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #17 on: 08/23/2007 11:46 PM »
The trick is getting the Al and O out of the surface, which is almost totally anorthosite, which is roughly the same chemically as portland cement. Meaning, in order to crack the regolith, no matter how you do it, you need lots and lots of energy, be it nuclear, solar electric, or solar thermal. Either way, you need quite an infrastructure to manufacture fuel on the Moon...

Simon ;)

Offline A_M_Swallow

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Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #18 on: 08/24/2007 12:50 AM »
Quote
simonbp - 24/8/2007  12:46 AM

The trick is getting the Al and O out of the surface, which is almost totally anorthosite, which is roughly the same chemically as portland cement. Meaning, in order to crack the regolith, no matter how you do it, you need lots and lots of energy, be it nuclear, solar electric, or solar thermal. Either way, you need quite an infrastructure to manufacture fuel on the Moon...

Simon ;)
Fortunately someone at NASA is already planning how to handle and reduce the regolith.
http://centennialchallenges.nasa.gov/

There is $1million price for getting the oxygen out.
http://www.californiaspaceauthority.org/moonrox/

I suspect that the first machine will have 6 months to produce sufficient oxygen and any materials like aluminium.  There is a lot of sun light in 6 months.  100kW solar panels should be available off the shelf by then.
6 months of power = 1/2 year in days * 24 hours * power / half night = 365/2 * 24 * 100kW / 2 = 219.000,000 W h

At 500 W/kg the array would weight 100,000 / 500 = 200 kg.  (Possibly twice that for the Moon.)

The machine could be sent up using J-120 (40mT) or Delta IV (23mT) including what ever takes it to the Moon and lands the machine.

Offline morganism

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Re: Making a Lunar Ascent rocket fuel on the Moon
« Reply #19 on: 03/16/2013 06:33 AM »
time for a re-exam with the volatiles turning up.

http://www.sciencedaily.com/releases/2009/10/
     091007161127.htm

and from the old moon miners manifesto MMM, a bunch of these are archived online now, try http://www.asi.org/adb/01/communicate.html

Moon Miners' Manifesto

#95 May 1996

Section 6.9.3.2.095.of the Artemis Data Book

Lunar Aluminum and Oxygen Propellants
LUNAR ALUMINUM and OXYGEN PROPELLANTS to SUPPORT LUNAR BASES and PLANETARY FLIGHT

by Larry Jay Friesen
MMM#95 - May, 1996


Introduction

It will greatly ease the long-term economics of supporting a lunar base to produce propellants at the Moon. These would be used for flights between the lunar surface and any near-Moon space stations, and from there back to Earth. It has even been proposed to supply lunar propellants to low Earth orbit (LEO) to be used for Moon-bound ships. This will come as no surprise to long-term students of lunar base proposals. The major reason is that traffic models for lunar base show that by far the largest budget item in mass being moved around between the Earth and Moon is rocket propellant.

Lunar propellant could also be used to launch inter-planetary space flights. This would be especially advantageous if those flights were launched from a near Moon staging base, such as the L1 Lagrange point space station proposed in the preceding article [MMM #94, April '96]. I am going to argue that the combination of an L1 base and lunar propellants would make a powerfully synergistic combination for suppor-ting both lunar and interplanetary ventures.

The most frequently proposed lunar-derived propellant is liquid oxygen extracted from the oxides and silicates that make up lunar rocks. This would be burned with hydrogen provided from Earth. One attraction of this is that the oxygen/ hydrogen combination provides one of the highest specific impulse values available from chemical propellants. Specific impulse is a performance measure for rockets somewhat analogous to miles per gallon. It is often given in units of seconds, meaning the number of seconds that one pound of propellant could produce one pound of thrust, before it is consumed. The few combinations known that produce higher specific impulse: (a) produce only slightly higher, not grossly higher, specific impulse; (b) are composed of more expensive materials; and (c) are more corrosive and difficult to handle.

One disadvantage of this, if one is trying to minimize mass lifted from Earth, is that the hydrogen will probably still have to be supplied from Earth. Hydrogen is extremely rare on the Moon [Ed. in general. We can hope that Lunar Prospector will confirm indirect indications from the Clementine mission that there is economically significant ice in the permashade areas at the lunar south pole. We should know by early '98, latest.] A minute amount is found implanted in lunar soil by the solar wind. It is conceivable that this can be extracted in amounts adequate for life support. However, the amounts of material that would have to be processed to extract enough hydrogen to support a reasonable amount of traffic to and from the Moon are far larger than I, for one, would find attractive.

Other propellant combinations based on lunar materials have been proposed. Silanes would stretch the terrestrial hydrogen by combining it with lunar silicon to make compounds analogous to methane and ethane. This would increase the proportion of the [total] propellant [combination] supplied from the Moon. However, it would also reduce specific impulse. Specific impulses of silanes burned with oxygen are roughly similar to those of hydrocarbons burned with oxygen, or in the range of 300+ seconds rather than the 400+ seconds of hydrogen and oxygen.

Advantages of Lunar Oxygen & Aluminum Together

A particularly appealing propellant combination is lunar oxygen plus lunar metals, especially lunar oxygen and lunar aluminum. Aluminum and oxygen alone will provide a specific impulse somewhat lower than most hydrocarbons. Brower et al. expect a value of 285 seconds [1]. However, this should be quite adequate for lunar landing, lunar liftoff, and departure for Earth from an L1 station using a lunar swingby trajectory. Lunar escape velocity is only 2.4 km/sec, so we don't need an enormous specific impulse for operations in the lunar vicinity. A big advantage of this propellant combination is that no terrestrial material at all is required. Keeping down the mass we have to lift from Earth is likely to be a major factor in keeping down the operational costs of our missions.

One means of enhancing the performance of lunar oxygen and aluminum could be to combine them with terrestrial hydrogen in a tripropellant engine. Andrew Hall Cutler [2] estimates that [with] an H:O:Al mass ratio of 1:3:3, such an engine would have a specific impulse exceeding 400 seconds - only slightly poorer than hydrogen and oxygen alone. This ratio also manages to decrease slightly the proportion of hydrogen that has to be brought from Earth, compared to the approximately 1:5 combustion mass ratio of H:O for Shuttle main engine technology. Brower et al. [1] expect that with an H:Al:O mass ratio of 1:2.5:2.75, a specific impulse of 475 seconds can be achieved. This would increase performance, but at the cost of bringing more hydrogen from Earth.

It might turn out that, for instance, lunar aluminum and oxygen alone would be best for a lunar lander flying back and forth between the lunar surface and an L1 staging base, while lunar aluminum and oxygen combined with terrestrial hydrogen would be more advantageous for a space-to-space lunar transfer vehicle (LTV) flying between the L1 station and LEO. Trade studies are needed to decide for what flight phases is is most advantageous (i.e. what minimizes mass launched from Earth) to use lunar aluminum and oxygen alone, and when it is best to add terrestrial hydrogen. How much hydrogen should be added to the propellant mix, weighing the cost of mass launch against performance gain?

It would also be worth doing trade studies to answer the question: would it be advantageous to ship lunar aluminum and oxygen propellants to LEO? When the overall mass flow in the system is considered, will that reduce mass launched from Earth? Further, would aerobraking for LTV return to LEO be useful in a transportation scheme making heavy use of lunar propellants? Or would the propellant used in hauling the aerobrake around exceed the propellant saved when braking into LEO?

If one wants to extract aluminum as well as oxygen from lunar materials, it means re-examining the extraction techniques. Reduction of ilmenite, for example, an often cited approach, will not do. Ilmenite reduction starts with a[n iron and] titanium-rich mineral found in lunar mare soil and produces oxygen, but no aluminum. Other oxygen extraction methods that do not produce aluminum will not do, either, at least not without steps added to get aluminum metal.

This also means carefully considering where on the Moon to go for raw material. Lunar maria are high in iron and titanium, but tend to run low in aluminum, only around 7%. The highlands, in contrast, are rich in an aluminum-rich material called anorthosite, and highland soil tends to be about 13% aluminum by weight [1]. If aluminum and oxygen are both target materials, the lunar highlands are the better place to go for feedstock. [Editor's qualifying comment follows article.]

Lunar Propellants for Interplanetary Flights

Lunar derived oxygen and aluminum propellants could also be used to aid the departure of interplanetary space flights, if those flights were launched from an L1 base on gravity slingshot trajectories as described in the preceding paper [3] [MMM # 94, April '96] If a "triple thrust" departure is used to go to Mars, for example, using both a lunar and an Earth flyby, the total velocity change or delta V (DV) needed to depart the lunar vicinity is only 350 meters [0.35 km] per second. DV gives a measure of the amount of energy and propellant needed to accomplish a maneuver, if you know the performance of the propellant combination your ship is using. The additional DV needed at perigee to place the ship in a Mars-bound trajectory is only 790 meters [0.79 km] per second.

It is quite conceivable that lunar settlers may one day produce oxygen and aluminum propellants for departure stages of planet-bound spacecraft, maybe with Earth-derived hydrogen added for extra performance. Lunar oxygen could well fill the oxidizer tanks of the interplanetary craft for the subsequent maneuvers in its itinerary. If the interplanetary ship designers select a tripropellant propulsion system, the ships may carry lunar aluminum as well, with only a small admixture of terrestrial hydrogen to boost specific impulse. Using lunar propellants combined with launching and retrieving interplanetary flights at L1 [3] could significantly reduce costs of interplanetary travel.

Ways to Implement Lunar Aluminum/Oxygen Propellant Usage

How are we to implement the use of lunar oxygen and aluminum propellants together?

One way would be to pump aluminum powder as we do fluids. In this case, it will probably be necessary to use a carrier gas along with the powder to keep the aluminum grains from vacuum welding or sticking together from electrostatic forces. Here we could use lunar hydrogen implanted in soil grains by solar wind, because only a small amount is needed. The hydrogen for this function does not have to be a significant fraction of the propellant.

Another technique is a hybrid rocket engine using solid aluminum and liquid oxygen. A conceptual design for such an engine was proposed by Brower et al. [1]. Their design calls for a hexagonal array of aluminum bars the length of the combustion chamber. Liquid oxygen would be fed down the bars for regenerative cooling before reaching the flame at the bar tips. The engine could use oxygen and aluminum only, or could use tripropellant operation with hydrogen.

References

[1] Brower, D., Adams, T. Kelly, C. Ewing, and T. Wiersema, "Conceptual Design of Hybrid Rocket Engines Utilizing Lunar-derived Propellant", AIAA paper 90-2114, delivered at AIAA/SAE/ASME/ASEE 26th Joint Propulsion Conference, Orlando, FL, (July 16-18, 1990).

[2] Cutler, Andrew Hall. "Aluminum Fuelled Space Engines for Economical Lunar Transportation". Lunar Bases and Space Activities of the 21st Century, W.W. Mendell, ed., Lunar and Planetary Institute, Houston, (1985) p. 61.

[3] Friesen, Larry Jay, "Lagrange Point Staging for Lunar and Planetary Flight", Moon Miners' Manifesto, issue # 94. April 1996, Milwaukee, WI.

LJF

[EDITOR'S COMMENT: MMM thanks Larry Jay Friesen for this excellent and enlightening pair of papers. However, his remarks on lunar base siting demand comment.

Those who do not foresee (or do not wish to speak to) the industrialization of the Moon, and are only trying to brainstorm the economics of renewed exploration activities, may indulge in the thought that efficient oxygen production is the only determinant of consequence when it comes to picking a site for a lunar base. But those of us who look forward to real, industrially self-supporting communities on the Moon must take a wider view. Lunar settlers will need access to all economically producible elements. From a lunar development point of view it is clear that we ought to put our outpost in a location from which both suites of materials (aluminum rich highlands, iron rich maria) can be accessed with equal ease - the highland-mare "coasts"! This solution is so self-manifest that the very continuance of this debate exasperates! Those who come from different disciplines must talk to one another!

PK

Contents of this issue of Moon Miners' Manifesto

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