MininginSpace — AIAA and New York Academy of Sciences On December 10, 1986 the Greater New York Section of theAmerican Institute of Aeronautics and Astronautics (AIAA) andthe engineering section of the New York Academy of Sciencesjointly presented a program on mining the planets. Speakers wereGreg Maryniak of the Space Studies Institute (SSI) and Dr.CarlPeterson of the Mining and Excavation Research Institute ofM.
I.T.Maryniak spoke first and began by commenting that thequintessential predicament of space flight is that everythinglaunched from Earth must be accelerated to orbital velocity.Related to this is that the traditional way to create things inspace has been to manufacture them on Earth and then launch theminto orbit aboard large rockets.
The difficulty with thisapproach is the huge cost-per-pound of boosting anything out ofthis planet’s gravity well. Furthermore, Maryniak noted, since(at least in the near to medium term) the space program mustdepend upon the government for most of its funding,for thiseconomic drawback necessarily translates intoapoliticalproblem.Maryniak continued by noting that the early settlers inNorth America did not attempt to transport across the Atlanticeverything then needed to sustain them in the New World.Ratherthey brought their tools with them and constructedtheirhabitats from local materials.Order now
Hence,he suggested that thesolution to the dilemma to which he referred required not somuch a shift in technology as a shift in thinking.Space,heargued, should be considered not as a vacuum, totally devoid ofeverything. Rather, it should be regarded as an ocean, that is,a hostile environment but one having resources.Among theresources of space, he suggested, are readily available solarpower and potential surface mines on the Moon and later othercelestial bodies as well.
The Moon, Maryniak stated, contains many useful materials.Moreover, it is twenty-two times easier to accelerate a payloadto lunar escape velocity than it is to accelerate the identicalmass out of the EarthUs gravity well. As a practical matter theadvantage in terms of the energy required is even greaterbecause of the absence of a lunar atmosphere. Among other thingsthis permits the use of devices suchaselectromagneticaccelerators (mass drivers) to launch payloads from the MoonUssurface.
Even raw Lunar soil is useful as shielding for spacestations and other space habitats.At present,he noted,exposure to radiation will prevent anyone for spending a totalof more than six months out of his or her entire lifetime on thespace station. At the other end of the scale, Lunar soil can beprocessed into its constituent materials. In between steps arealso of great interest.
For example, the MoonUs soil is rich inoxygen, which makes up most of the mass of water and rocketpropellant. This oxygen could be RcookedS out of the Lunar soil.Since most of the mass of the equipment which would be necessaryto accomplish this would consist of relatively low technologyhardware, Maryniak suggested the possibility that at least inthe longer term theextractionplantitselfcouldbemanufactured largely on the Moon. Another possibility currentlybeing examined is the manufacture of glass from Lunar soil andusing it as construction material.
The techniques involved,according to Maryniak, are crude but effective. (In answer to aquestion posed by a member of the audience after the formalpresentation, Maryniak stated that he believed the brittleproperties of glass could be overcome by using glass-glasscomposites. He also suggested yet another possibility, that ofusing Lunar soil as a basis of concrete.)One possible application of such Moon-made glass would bein glass-glass composite beams.
Among other things, these couldbe employed as structural elements in a solar power satellite(SPS). While interest in the SPS has waned in this country,atleast temporarily, it is a major focus of attention in theU.S.S.
R. , Western Europe and Japan. In particular, the Sovietshave stated that they will build an SPS by the year 2000(although they plan on using Earth launched materials. Similarlythe Japanese are conducting SPS related sounding rocket tests.
SSI studies have suggested that more than 90%,and perhaps asmuch as 99% of the mass of an SPS can be constructed out ofLunar materials.According to Maryniak, a fair amount of work has alreadybeen performed on the layout of Lunar mines and how to separatematerials on the Moon. Different techniques from those employedon Earth must be used because of the absence of water on theMoon. On the other hand, Lunar materials processing can involvethe use of self-replicating factories.
Such a procedure may beable to produce a so-called Rmass payback ratioS of 500 to 1.That is, the mass of the manufactories which can be establishedby this method will equal 500 times the mass of the originalRseedS plant emplaced on the Moon.Maryniak also discussed the mining of asteroids usingmass-driver engines, a technique which SSI has long advocated.Essentially this would entail a spacecraft capturing either asizable fragment of a large asteroid or preferably an entiresmall asteroid.
The spacecraft would be equipped with machineryto extract minerals and other useful materialsfromtheasteroidal mass. The slag or other waste products generated inthis process would be reduced to finely pulverized form andaccelerated by a mass driver in order to propel the capturedasteroid into an orbit around Earth. If the Earth has so-calledTrojan asteroids, as does Jupiter, the energy required to bringmaterials from them to low Earth orbit (LEO) would be only 1% asgreat as that required to launch the same amount of mass fromEarth. (Once again, moreover, the fact that more economicalmeans of propulsion can be used for orbital transfers than foraccelerating material to orbital velocity would likely make thepractical advantages even greater.
) However, Maryniak noted thatobservations already performed have ruled out any Earth-Trojanbodies larger than one mile in diameter.In addition to the previously mentioned SPS,anotherpossible use for materials mined from planets would be in theconstruction of space colonies.In this connection Maryniaknoted that a so-called biosphere was presently being constructedoutside of Tucson, Arizona. When it is completed eight peoplewill inhabit it for two years entirely sealed off from theoutside world.
One of the objectives of this experiment will beto prove the concept of long-duration closed cycle life supportsystems.As the foregoing illustrates, MaryniakUs primary focus wasupon mining the planets as a source for materials to use inspace. Dr. PetersonUs principal interest, on the other hand, wasthe potential application of techniques and equipment developedfor use on the Moon and the asteroids to the mining industryhere on Earth.
Dr Peterson began his presentation by noting thatthe U. S. mining industry was in very poor condition.Inparticular, it has been criticized for using what has beendescribed as Rneanderthal technology.
S Dr.Peterson clearlyimplied that such criticism is justified, noting that the sooneror later the philosophy of not doing what you canUt make moneyon today will come back to haunt people. A possible solution tothis problem, Dr. Peterson, suggested, is a marriage betweenmining and aerospace.
(As an aside, Dr. PetersonUs admonition would appear to beas applicable to the space program as it is to the miningindustry,and especially to the reluctance ofboththegovernment and the private sector to fund long-lead time spaceprojects. The current problems NASA is having getting fundingfor the space station approved by Congress and the failure beginnow to implement the recommendations of the National Commissionon Space particularly come to mind.)Part of the mining industryUs difficulty, according to Dr.
Peterson is that is represents a rather small market. This tendsto discourage long range research. The result is to produce onthe one hand brilliant solutions to individual,immediateproblems, but on the other hand overall systems of incrediblecomplexity. This complexity, which according to Dr.
Peterson hasnow reached intolerable levels,results from the fact thatmining machinery evolves one step at a time and thus is subjectto the restriction that each new subsystem has to be compatiblewith all of the other parts of the system that have not changed.Using slides to illustrate his point, Dr. Peterson noted thatso-called RcontinuousS coal mining machines can in fact operateonly 50% of the time. The machine must stop when the shuttlecar, which removes the coal,is full.
The shuttle cars,moreover, have to stay out of each others way. Furthermore, notonly are Earthbound mining machines too heavy to take intospace, they are rapidly becoming too heavy to take into mines onEarth.When humanity begins to colonize the Moon,Dr.Petersonasserted, it will eventually prove necessary to go below thesurface for the construction of habitats, even if the extractionof Lunar materials can be restrictedtosurfaceminingoperations.
As a result, the same problems currently plaguingEarthbound mining will be encountered. This is where Earth andMoon mining can converge. Since Moon mining will start fromsquare one, Dr. Peterson implied, systems can be designed as awhole rather than piecemeal.
By the same token, for the reasonsmentioned there is a need in the case of Earthbound miningmachinery to back up and look at systems as a whole.What isrequired, therefore, is a research program aimed at developingtechnology that will be useful on the Moonbutpendingdevelopment of Lunar mining operations can also be used downhere on Earth.In particular, the mining industry on Earth is inhibitedby overly complex equipment unsuited to todayUs opportunities inremote control and automation. It needs machines simple enoughto take advantage of tele-operation and automation.
The sameneeds exist with respect to the Moon.Therefore the mininginstitute hopes to raise enough funds for sustained research inmining techniques useful both on Earth and on other celestialbodies as well. In this last connection, Dr. Peterson noted thatthe mining industry is subject to the same problem as theaerospace industry: Congress is reluctant to fund long rangeresearch.
In addition, the mining industry has a problem of itsown in that because individual companies are highly competitiveresearch results are generally not shared.Dr.Peterson acknowledged,however,that there aredifferences between mining on Earth and miningonotherplanetary bodies.The most important is the onealreadymentioned-heavy equipment cannot be used in space.
This willmean additional problems for space miners. Unlike space vacuum,rock does not provide a predictable environment.Furthermore,the constraint in mining is not energy requirements,but forcerequirements. Rock requires heavy forces to move.
In otherwords, one reason earthbound mining equipment is heavy is thatit breaks. This brute force method, however, cannot be used inspace. Entirely aside from weight limitations,heavy forcescannot be generated on the Moon and especially on asteroids,because lower gravity means less traction. NASA has done someresearch on certain details of this problem, but there is a needfor fundamental thinking about how to avoid using big forces.
One solution, although it would be limited to surfacemining, is the slusher-scoop. This device scoops up material ina bucket dragged across the surface by cables and a winch.Oneobvious advantage of this method is that it by passes lowgravity traction problems. Slushers are already in use here onEarth.
According to Peterson, the device was invented by aperson named Pat Farell. Farell was, Peterson stated,a veryinnovative mining engineer partly because be did not attendcollege and therefore did not learn what couldnUt be done.Some possible alternatives to the use of big forces werediscussed during the question period that followed the formalpresentations. One was the so called laser cutter.
This,Peterson indicated, is a potential solution if power problemscan be overcome.It does a good job and leaves behind avitrified tube in the rock.Another possibility is fusionpellets, which create shock waves by impact. On the other hand,nuclear charges are not practical.Aside from considerationsgenerated by treaties banning the presence of nuclear weapons inspace, they would throw material too far in a low gravityenvironment.