|| Tech || Culture || Activities || Resources || Links || Weblogs || Features ||
Site Info
Space Tech
Near Space
Satellite Building
Satellite Observing
Space Science
Space Simulators
Space Culture
Solar Sci-Fi
TV Space
More Activities
Space Camping
Space Tourism
Books & Magazines
Eyes in the Sky
Future Space
Multiple Media
Software Offline
Software Online
Link Lists
News, Blogs, Forums
General Space
Science & Technology
Space For All
NewSpace Watch
Experimental Rocketry
In Space Now
Special Topics
Shopping Guide
Site Info
About HS
Advertise at HS
What's New






Toroidal Colony - by Don Davis

A Space Roadmap: Mine the Sky,
Defend the Earth, Settle the Universe

by Dr. Lee Valentine

Space for All Blog
Space Transport News blog
Space Activism
Life in Space, Space Settlements

Lee Valentine is a physician, a long time space advocate, and a director of the Space Studies Institute. This article came from a briefing he gave to the Aerospace Technology Working Group (ATWG) at the Space Infrastructure Development: Near Earth meeting in Phoeniz, AZ, May 2002.

[Update: Here are two interviews with Dr. Valentine on the SpaceShow:


Abstract: Preservation and prosperity of humanity on the Earth and human settlement of circumsolar space is the goal, we must concentrate on a commercial path to get there. NASA must enable new markets, not compete in them. Nonterrestrial materials are the key to opening the space frontier and should be the focus of new NASA initiatives. NEO mining serves two purposes, defense and material supply. Scientific missions must be undertaken to assay resources and plan NEO diversion. Use the advantages of space: manufacture and assemble in space.

Space solar power is a trillion dollar market and should be fully explored, and NASA is crucial to this effort, platinum group metals will eventually be important. Obtaining economic benefits from commercial space including tourism and space solar power and platinum group metals as well as traditional markets should be the major thrust of our space enterprise.

Man to Mars is a diversion we can't afford. Human settlement of the space frontier is an end in itself but will follow naturally large-scale extraction of nonterrestrial resources and construction of space solar power stations, either on the moon or in orbit. Space tourism is a real market and the necessary evolution from small stations like Mir and ISS to real space hotels will necessitate the incorporation of fully closed life-support systems. These could be considered the first space colonies. The likelihood is that space tourism will greatly drive down the cost of space access over the next two decades. Space tourism may even provide a relatively near term market for lunar or asteroidal water.

New deep space transportation modes are needed, NASA has a clear role here. Mining and fabricating technologies need development. Advanced robotics and telepresence will allow orders of magnitude improvement in human productivity, but humans will be required for the next two decades in supervisory roles, most particularly, in an unstructured environment such as an asteroid mine. We see a path that requires much less capital investment than Gerard O'Neill's original plan to mine the moon and build both large space colonies and power satellites in tandem. Furthermore, this new roadmap will allow evolutionary improvements in technologies for building both power satellites and space colonies and protecting the earth from NEO impact.

I would like to discuss what I think we should be doing in space and why we should be doing it.I would like to talk about things that might be done in the next 20 years. I would like to talk about an evolutionary roadmap that will enable us step-by-step to defend the earth, to mine the sky and to settle the universe. I would like to talk about things that can be done with near-term technology but emphatically I would like to talk about space.

Space is not Mars. Mars is a planet with planetary disadvantages. The moon is a little closer to space, and the asteroids are convenient mines already in space. Free space is where the energy is and where we should settle, and that is what I would like to talk about.

In the immortal words of Dennis Tito, "I love space."

The existence of the Space Studies Institute is predicated on the idea that free space is a natural home for an advanced technological species and that in the not too distant future most human beings will not live on the surface of the earth but rather will inhabit free space colonies in orbit about the sun.

The idea is technically feasible. The early designs required techniques no more advanced than those standard in bridge and shipbuilding three decades ago. The great difficulty it seems, is making the transition from a government run space program, designed to defeat our political rivals, with handcrafted machines, whose cost is equivalent to their weight in precious metal, to a scenario in which machines are built from non-terrestrial materials for commercial purposes using automatic construction machines: the economically driven settlement of circumsolar space.

Why economically driven?Well, most of us here would like to see another space macro engineering project like Apollo. Many would like to see a manned mission to Mars and, at the Space Studies Institute, 20 years ago we were very much hoping to see a fast-paced macroengineering project begun to mine the moon and build solar power satellites and large space colonies, all at the same time. We worked as hard as we could for some years to try to bring that about. The advocates for manned Mars missions have done the same.

Neil Tyson points out that there are three historic rationales for macroengineering projects. And some macroengineering projects have as reasons a combination of them. The first rationale is warfare.The Great Wall of China falls into this category.

The second is as a monument to power. The Egyptian pyramids and St. Peter's Cathedral fall squarely into this one.

"Colony construction crew at work" (large)
Don Davis - NASA Space Colony Artwork

The third reason is to make a big pile of money. Canals and railroads and communications satellites are examples. The development of the vast civil infrastructure of the United States logically falls into this third category. Of course, like Roman roads, some projects may have both military and commercial use. The pyramids now earn valuable foreign exchange for Egypt as tourist attractions.

The motivation for Apollo was partly warfare aimed to defeat the Soviet Union and partly a monument to power. In a paragraph of his famous Rice speech, rarely quoted, John Kennedy refers to the moon race with the Soviet Union as a battle in a war. It is clear from Kennedy's subsequent conversations with James Webb that Kennedy saw no other purpose in space development. There was no thought of economic return.

The United States is now the world's only military and economic superpower, and we have no need for further monuments to our prowess. There is a military need for low orbit application satellites to prosecute our war against a dispersed enemy, but that does not take us necessarily where we want to be in terms of space colonization and development.

A manned Mars mission in the near-term would be a monument to power. In the present political climate, the American public will not support that and neither will its elected representatives in Congress. A manned Mars mission, furthermore, holds promise only of large negative economic return. Indeed, my old colleague Tom Paine estimated that colonizing Mars would consume one trillion dollars big fat 1979 dollars in tax money over a century.

We should take a somewhat longer term view. Is there any particular reason to expend significant national resources now to send a small crew of humans to Mars while stretching technology to the limit?There isn't one that I can see.

That leaves us with only the third option of finding some way of making a large pile of money in the space business if we are to hope to realize the dreams that we all share. In this decade, the petroleum industry will spend one trillion dollars on infrastructure development and the electric power industry will spend several hundred billion dollars annually building base load power plants. It is difficult to predict the market for platinum group metals, but should satisfactory mining of asteroids take place for other purposes it appears likely to me that platinum group metals will be an important byproduct. The exploration and development of space is going to be increasingly dependent on economic criteria.

I will talk very briefly about space science and would like to point out something and that is the enormous amount of geological knowledge that has resulted from road cuts, railroad cuts and quarries in the developed world. Our scientific colleagues have got to realize that with space development comes the potential for much greater scientific return than they could ever justify based on peer reviewed curiosity. Pure science in many ways is a misnomer; science has always advanced in leapfrog fashion with improving technology and economic development.

A similar argument can be made for exploration. James Cook's ship Endeavor was a converted Whitby collier. I would pose the question this way: would it have made sense for James Cook to attempt exploration of Antarctica in the 1700s? He plainly had the sea faring prowess to do it. It is equally plain that his best hope might have been to merely make land fall on its shores and dally for a moment in summer before sailing north again. We should explore Mars firsthand when the National Geographic Society can pay for it. So let's see how commercial space development plans and technologies can make our scientific colleagues and would-be Mars explorers happy, too.

The human enterprise in space really does need to orient itself to the needs of a community larger than the space science fraternity and when it does so effectively, piles of money and perhaps more importantly a fund of new technology will become available to accomplish those objectives that are now enormously expensive yet greatly desired on the part of space scientists. That is certainly not to disparage the value of the scientific community in opening the space frontier, I will mention the value of the forthcoming European Gaia probe and other probes such as Near Shoemaker and Deep Space One have been invaluable. It appears plain that a large number of near earth objects will have to be sampled and assayed and physical characteristics measured in order to provide necessary planetary defense, too.

I'm not a big genius so I will not describe for you how to grow space colonies from seeds, that is Freeman Dyson's purview. I do not doubt that this is possible at sometime in the future but I do not know when that future will be.What I would like to discuss is how to build an evolutionary space program that can potentially be made profitable every step of the way and allow the gradual settlement of that new frontier. This is the way our country was built and provides a distinctly different model from the construction of the pyramids. I would like to discuss the vast materials and energy resources available to human race in orbit and some of the reasons that it made the concept of free space colonies so congenial to brilliant minds in the past.

Almost a hundred years ago, in 1903, Tsiolkowskii wrote "Beyond the Planet Earth". Living through the cold dark Russian winter gave him perspective on the value of full-time unimpeded sunlight for raising crops and powering industry. Interestingly, in that book he describes returning gold and precious stones from asteroids to make his scheme of space settlement economically viable.

In those far off days, he was searching for an economic driver just as we are today. It seems unlikely that we will find gem quality diamonds on asteroids in quantities to sufficient to pay for a space settlement scheme. We do know now, however, that there are materials of enormous economic interest available in space. Those materials are the platinum group metals. Any near earth object has a platinum group metals concentration greater than the best terrestrial ores.

There is energy, too. Since you are engineers I thought you would naturally like to have some equations, so here are some beautiful equations.

The formula for the surface area of a sphere is 4pi*r^2. The great thing about this equation is that it allows us to calculate the sun's power output from knowledge of the solar flux and our mean distance from the sun and we find that it is an enormous number.

The formula for the lateral area of a cylinder is 2pi*rh. This equation allows us to calculate how much of that solar energy might be available to large power satellites in geostationary orbit.

So from these two nice equations it's possible to see that we have, if we're clever, a great energy future in space. The energy output of the sun is about 3 times 10 ^14 terawatts so you can see there's plenty of energy to power a much expanded human population provided we go where the energy is. The energy falling on a 15 km wide band of geostationary orbit is about 2500 terawatts. That is a much smaller number but still very large compared to our present rate of energy use. World energy consumption last year was 11 terawatts. We would need only 20 terawatts to give everyone living in 2050 the current US per capita energy consumption.

It is plain to see that there is energy to spare even in geostationary orbit. There are plenty of terawatts even if power satellite conversion and transmission efficiency from geostationary orbit is only 25 percent, a number easily achievable with present-day technology.

Well, where should we obtain materials to build these power satellites? The argument that I would like to make is that the best source for raw materials for building power satellites is not mines on the Earth but rather it is the moon or near Earth objects.

Engineers also like data. Here are a few: 1 in 10^-6, 1 in 10^-3, 1 in 10^-2. The first number refers to the likelihood of a mass extinction impact per century from asteroid or comet impact, the second is the rough likelihood per century of a NEO impact sufficient to ruin civilization and kill a billion people, the third is the likelihood over the next century that an impact generated tsunami will destroy the East or West coast. Those numbers should worry all of us.Our children and grandchildren will be alive throughout most of the century.

What has become plain from the scientific results of Apollo and Mariner and Spacewatch is that the one thing that the human race must learn how to do in space is to defend our planet from catastrophic impacts with near earth objects. This idea appears to be something so new that it has not yet penetrated the popular consciousness fully, despite Hollywood movies about the topic. It certainly has not yet fully penetrated the consciousness of the decision-makers in Washington. There is a great need for targeted reconnaissance of representative spectral types of asteroids and comets. That means at least twenty rendezvous missions. Many more landings on those bodies and their physical characterization will be necessary to plan for their deflection or utilization.

Deflection technology is not the sole purview of the Defense Department, most particularly since their preferred solution appears to be the use of nuclear explosives. The political realities of this are that deployment of such explosives is now illegal under international law and there is widespread popular feeling in the advanced countries that such techniques should be a last resort. Should a threatening object be discovered tomorrow to impact in a few weeks time, civil defense would be the only option.

Other options exist like mass drivers and solar thermal rockets and solar sails, things that improve deep space transportation and transportation to geostationary orbit and things that are specifically mentioned in the NRC report evaluating NASA's satellite solar power effort. Mass drivers, indeed, may turn out to be the best option for moving some asteroids. Development and testing of mass drivers, advanced solar sails, and other advanced propulsion technologies for the purpose of NEO deflection is something that NASA should have on the front burner.

These technologies are dual use. They work equally well to return NEO's to earth orbit to supply materials to construct satellite solar power stations or to construct or provision space hotels, or provide platinum group metals to the terrestrial fuel cell market as they do to deflect threatening near earth objects. Another key enabling technology might be the use of laser launching for access to orbit.

Curiosity driven science for the primary benefit of academics is likely to continue its slow and steady decline in importance to the man in the street and his elected representatives in Washington. Improvements in capabilities in the private sector should allow NASA's scientific missions to be conducted more cheaply. Generally, the figure of merit for engineering purposes is dollars per unit of some service. Because launch cost dominates the price of machines on orbit we have become irrationally fixated on their MASS per unit service rather than COST per unit service. Neither watts per kilogram radiated nor mass payback ratio nor hours of flight per man hour of maintenance nor any metric other than cost per unit service should be our figure of merit.

Let's see what might happen if we ignore mass and use cost per kWh as our figure of merit, assume we have an adequate quantity of nonterrestrial material available and are able to do design and construction for cost rather than for mass considerations.

What happens to the price of electricity from a power satellites if 95 percent of the mass is constructed from nickel steel alloy and rock obtained from an asteroid? Well, if you assume a Brayton cycle turbine, state-of-the-art 1995 at 20 watts/ kg output, and assume construction cost similar to machinery of similar complexity you have a nice installation with no fuel cost and an installed cost of about a thousand dollars per kilowatt, very competitive with terrestrial base load power. You produce 8760 kWh the first year. Not bad. You should be able to make nice money that way even with a hefty discount rate. Of course, this assumes a space manufacturing facility capable of marginal production costs similar to terrestrial industries.

The cost of satellite solar power is now dominated by the launch cost; this gives us reason to pursue sources of material that do not require launching. This brings us naturally to lunar or asteroidal resources. It is impossible today to decide which of these two would be the better. One thing is certain, however; we do not have processes already developed to get all the materials that we are sure we'll need to construct our satellite. We need to develop those processes and it is the proper purview of NASA to fund that development.

While it seems likely that nearly all the mass of a solar photovoltaic power satellite can be constructed of lunar derived material,that is not to say that this design solution is optimal. It may be that a Brayton cycle turbine powered satellite constructed of asteroidal material would be cheaper. That is particularly true if metallic asteroids were to be found in the earth sun Lagrange orbits. Furthermore, the lunar power system described by David Criswell has several advantages over Peter Glaser's classic geostationary solar power satellite. It does not require the launch of large masses of material to a precise point in space. On the other hand it does require precise pointing of a power beam over an order of magnitude larger distance. The lunar power system also suffers the disadvantage of an annual power outage lasting a lengthy three hours.

We can imagine a point, sometime in the future, where the manufacturing cost per unit mass is as low in space as it is on the surface of the Earth. Well before that time, however, space manufacturing will have an advantage in the construction of plants for base load power. At some time, slightly more distant, we can imagine that the manufacturing cost of space derived materials will be cheaper than those produced on the surface of the earth for the simple reason that one of the primary inputs, energy, will always be much cheaper in space.

The question, though, is complicated and David Criswell is one of the few making a determined effort now to give some answer to part of the question. The National Research Council specifically stated, twice, in "Laying the Foundation for Space Solar Power" that its review was of the existing NASA effort and they explicitly did not consider nonterrestrial materials scenarios.

We should not assume that launching a power satellite from the earth is necessarily the best way to build the first commercial power satellites. A design study baselining nonterrestrial materials for power satellite construction is something that should logically be done. If such a study were well and carefully performed, it might prevent power satellite advocates from heading down the wrong path for a decade or two.

It is useful to remember that the infrastructure of our mighty nation was built bit by bit and I am suggesting that that is the way we must develop space. The era of Apollo projects and manned missions to Mars, for no economic purpose, appears to be long gone.The ISS now serves as a monument to power, if it is to serve as our beachhead on the space frontier, we've got to find ways for it to enable things that people will ultimately be willing to pay for.

Can we discover a path that allows us to defend the Earth, as we must do, against asteroid and comet impacts and allows us to provide unlimited clean energy to improve our quality of life and the environment of our planet and also allows us to settle the solar system and begin our exploration of the rest of the universe? Can we find a path that allows us to make a profit and improve our technologies step-by-step? I think that there is. The technology for deflecting asteroids is also the technology for returning them for mining purposes. With a cheap source of materials power satellites, broadly understood, may be more than cost-effective, they may provide the cheapest possible electrical power. We need to do the things that enable us to stay on that righteous path.It is possible to envision an energy regime in the next 40 or 50 years that is almost completely powered from space and that furthermore uses platinum group metals largely derived from asteroids to enable a cheap, hydrogen mediated energy sector.

We should be thinking about the advantage of constructing things in space well away from planetary shadows.

Space has enormous advantages over planetary surfaces for construction of large structures. The full-time solar energy for electricity and thermal process heat is readily at hand. A hard vacuum makes possible processes that are extremely expensive to use on the earth. For example, very high-performance solar sails can be constructed by vapor deposition of aluminum, allowing performances orders of magnitude better than deployable solar sails, such devices are too fragile to deploy. The perfection of such devices should open up the entire inner solar system to commerce.

Now, application satellites are limited in their performance by costs which are driven by the necessity that they survive the rigors of launch and that they self-deploy. If large application satellites were to be constructed in space from components, larger more capable and rugged, and hence more valuable, satellites might be built for less money. Think about a growth path for satellites constructed on orbit and how that might compare to self-deployed satellites. Which way will be easier to eventually produce large, high-powered, low earth orbit communications relays or large high-powered geostationary platforms, for that matter. Assembling such large communication satellites will give us valuable practice in assembling even larger structures that will eventually become power satellites and furthermore that it may soon be beneficial to incorporate materials mined from the asteroids or the surface of the moon in such spacecraft. An early use of this technique that would be particularly applicable to manned space missions would be the use of water obtained from the moon or from a burnt out comet core for shielding and reaction mass. This is the same kind of evolutionary path followed by the United States as it made the transition from cow paths to dirt roads to early turnpikes then to modern superhighways.

In the past 20 years it has become apparent that we need not go to the asteroid belt to search for easily accessible resources. This idea is based on science that was unknown at the conclusion of the Apollo program 30 years ago. The near earth asteroids were discovered in the middle of the last century, but no one had any good idea of their quantity available until the last two decades.

A trickle of discoveries came after the establishment of Spacewatch, a development supported financially by the Space Studies Institute. The Alvarez discovery of the impact demise of the dinosaurs added further urgency to the discovery and accurate characterization of the size and numbers of near earth objects.SSI supported the Ph.D. thesis of the young physicist, who following a suggestion of Hannes Alfven, showed that there could be objects in reasonably stable orbits about the L4 and L5 Lagrange points in the earth sun system.

When the European probe Gaia is launched at the end of this decade, we will be able to discover asteroids in those most accessible orbits, one asteroid already has been discovered in an analogous orbit about a Mars Lagrange point and there are suggestions of material in one of the earth's Lagrange points.

Professor Ed Belbruno of Princeton has discovered a clever technique to return mass from these locations to geostationary orbit for a nominal change in delta V using a lunar resonance capture orbit. Many bodies in these highly accessible earth-crossing orbits will also be easily returnable to geostationary earth orbit. Ed Belbruno has done detailed calculations showing that this is so.NEO's in halo orbits about the Lagrange points in the Earth sun system are still hypothetical. Nonetheless, if a concerted effort is made to find them, even small ones of the proper composition could be enormously valuable. A metallic asteroid 100 meters in diameter has a mass of roughly eight million tons, this would be sufficient to construct most of the mass of 80 five Gigawatt satellite solar power stations.

The research needs here are obvious, how does one move such an asteroid? How does one cut up and maneuver the fragments of metal? How does one formulate the alloys and fabricate the structures? Although there is a large body metallurgical knowledge on hand that has been developed for terrestrial purposes, that knowledge may not be directly translatable to the space environment. We need experiments and we need prototypes, in that order.

As an aside, asteroidal metal was instrumental in opening the mines of Sudbury, but that is another story. With perhaps 5000 metallic asteroids like this in earth crossing orbits there will be no need to go to the main belt for longtime to come. That, of course, is not to say that the other classes of asteroid not be even more valuable.

The question then becomes how to leverage NASA's resources to enable the near-term use of space resources and at the same time enable a broad commercial sector to grow up in space. Fostering of new markets would include three things that are relatively easy to understand. The first is space tourism. It may seem unreasonable to include space tourism as something that would enable broader use of space by NASA but there are several ways in which this might come about. The first, and seemingly, most obvious one is to bring launch costs down through greater flight rates and market competition. We have seen at least some competition related cost reduction occur in the worldwide geostationary launch market over the last decade. That market is too small to give the impetus that a robust space tourism market would provide.

NASA may have work to do on propulsion and thermal protection in support of this new industry.

The next way that space tourism may benefit far frontier exploration is in the development of robust biologically based closed environment life-support systems to provide consumables for the visitors at a space hotel. Studies conducted by Boeing two decades ago showed that the crossover for a fully closed life-support systems occurred with a mission duration of somewhat less than five years. Well, I don't know of any hotel that is built with less than a five-year lifetime, so would make economic sense to incorporate a fully regenerative life-support system in the baseline design of such a facility. The trouble is, no one has yet built a completely close system with the robust functionality that would be necessary to serve this purpose. We all understand that closed ecologies are a critical technology for space settlement, but they are vital not just for permanent settlement. Until transportation costs to earth orbit are in the range of dollars per pound they will be economically important for any human space enterprise lasting longer than a few years. Space hotels and NEO mining and planetary missions are examples. These offer other routes to space colonization.

The failure to develop this critical spacefaring technology is an indictment of our national space enterprise.

We have had small-scale examples of materially closed systems that function reliably indefinitely. Their only requirement is an adequate supply of light. Over the past two decades, agricultural engineering has produced a number of functional modules for waste reprocessing that would form building blocks of a complete system. We have ideas about how the various functional modules might be integrated.

We've had some false starts and some bad ideas have been shaken out. The Biosphere 2 project gave rise to a new myth. Because of this well-publicized fiasco, many people, including very clever people with Ph.D.'s in physics, concluded that it is terribly expensive to construct a closed environment life-support system and despite the expenditure of hundreds of millions of dollars they don't work very well. The Biosphereans achieved the exact opposite of their stated goal of opening the space frontier. They have convinced people that closed ecologies are dangerous, fragile and expensive and, therefore, that space settlement is pseudoscience. That is why is so important to produce a functioning robust closed ecosystem, just to show that it can be done. A single functional system will provide a takeoff point for evolutionary improvements.

It is not important to understand the behavior of plants and animals in microgravity to construct closed ecologies for use in space. Most of the difficulty in designing a closed environment system for zero gravity is the handling of liquids.It is very difficult to handle liquids, especially unconstrained ones, not to mention waste matter, in microgravity. It is vastly simpler to provide rotational artificial gravity that allows plants to grow in the normal fashion and allows normal handling of liquids.Because it is a fifteen year project, the ISS would benefit enormously from a CELSS. The lack of artificial gravity, however, makes the construction of one there infeasible.

Similarly, manned Mars missions are designed to be multiyear affairs and since a cycling spaceship is a long duration facility with a lifetime of many years it would logically also have a fully closed life-support system. Space settlements, that is to say, space colonies of the O'Neill type located in full sunshine have significant advantages over facilities in low Earth orbit but they do share the commonality of need for biological closed environment life-support. We have shown in the work at Cornell quite plainly what should be intuitively obvious to any agricultural engineer and that is that free access to the proper spectrum of sunlight 24 hours a day vastly simplifies the design of such a closed environment life-support system.

Despite the crying need for such a system, and despite the demonstration that such systems are possible, none yet suitable for space settlements or indeed more modest missions has been developed. Such development is clearly within the purview of NASA's mission and should be undertaken with the idea that the survival and prosperity of the human race may depend on it.

Later on, genetically engineered plants adapted to full-time sunlight should theoretically allow you to decrease by half the mass of your plant material. You might also design the plants for production of more nutritious foods with a better nutrient balance. Beta-carotene has been engineered into rice to alleviate vitamin A deficiency, a common problem in the poorer rice dependent countries. This yellow rice has led to a lot of trouble with the screwball fringe of the environmentalist movement, but there's no question in my mind that the production of other such new plants could be a great boon to the poorer fraction of humanity as well as a benefit to space settlers.

An argument often made against the use of nonterrestrial resources for things like power satellite is that the required industrial infrastructure would cost one trillion dollars. I think that number is grossly mistaken. According to Mark Sonter, sending a few tons of equipment to a suitable core might return hundreds of times its weight in water, which could comprise most of the mass of a Mars bound spaceship with a CELSS. That would certainly appear to be true in the case of these easy Lagrange orbits.

A similar scenario can be devised for lunar polar ice. If you choose the lunar option you may teleoperate from Earth. It's hard to imagine a few tons of equipment costing a trillion dollars.

Here is a scenario for using easily extracted material to enable a manned Mars expedition that would also open the resources of the moon for use. The idea is to construct a large transit vehicle fueled with water from the moon and using lunar water as shielding and to supply the closed environment life-support system. The ship could be propelled by a relatively high thrust mass driver, a device not particularly sensitive to the source of its reaction mass.

Much is been made of the dangerous radiation environment faced by human explorers in transit to Mars. There are two general solutions to this problem. One is to make the transit time short, which could be achieved using nuclear propulsion. A longer transit time could be accepted if the crew were adequately shielded. Unfortunately adequate shielding requires meters thick walls. The thin aluminum shell of a spacecraft like Apollo emits secondaries exacerbating the radiation problem. One answer to the radiation problem is the development of a cycling spaceship most of whose mass is derived from lunar or asteroidal sources and for which reaction mass has also been derived from those sources.

There's no pressing need to get to Mars. We should wait until the resource base on the moon or asteroids has been developed to allow scientific research to be conducted in a sensible and cost-effective manner. At enormous cost, it would've been possible to maintain a tiny base at the South Pole in the early part of the last century but in fact, such a base did not become a reality until commercial air transportation was available to supply it.

The idea of the flags and footprints mission to Mars in the next 15 years does not resonate with the American public nor indeed would I endorse it. I would strongly argue that the way to explore Mars is firstly to establish a resource base that would be piggybacked off commercial enterprises, build a cycling spaceship largely from nonterrestrial materials, and conduct exploration using maximal telepresence robotics from the safety of Deimos or Phobos.

After a robotic beachhead is established on the surface of Mars and propellant factories established and shelters constructed, then would be the time to explore our sister planet firsthand in detail. The idea of expending several billion dollars in the meantime on a robotic mission to pick up a few Martian rocks and return them to Earth strikes me as entirely nutty. If Mars rocks have such great allure, we should study the ones that we have our possession already. At the price of Mars sample returns the extant Mars rocks should be worth more than a million dollars per gram when in point of fact anyone can buy them for vastly less than that on the open market.

In light of all of this, I would recommend the following for research topics that will help enable humankind to explore and settle circumsolar space and to defend this planet from the danger of asteroid and comet impacts.

  1. Construct and demonstrate a totally closed environment life-support system
  2. Evaluate nonterrestrial resources for SSP construction
  3. Investigate the use of teleoperated robots in NEO-mining and space construction
  4. Search for NEO's and design a program to assay their mineral resources
  5. Advance technology readiness level of mass driver and high performance solar sail technology and
  6. Vigorously pursue laser launch technology.

Finally, here is a suggested motto: Mine the Sky, Defend the Earth, Settle the Universe

The author is indebted to Eric Anderson, Ed Belbruno, James Burke, Eric Drexler, Freeman Dyson, George Friedman, Tom Gehrels, Peter Glaser, William Jewell, John S. Lewis, Les Snively, Neil DeGrasse Tyson, William “Red” Whittaker, and Gordon Woodcock for discussion of the ideasexpressed in this paper. Any fault of interpretation rests with the author.

Copyright 2002 Space Studies Institute, Princeton

Space for All Blog
Space Transport News blog
Space Activism
Life in Space, Space Settlements


Photo To Space
The Art of C. Sergent Lindsey
XCOR Aerospace
New Space Watch

Planet Globes at Spacetoys
, the Moon & other celestial globes at

The Nerds Coupons



Home  |  Directory  |  Advertising  |  About  |  Contact  |  Disclaimer
1999-2013 HobbySpace, All Rights Reserved.
HobbySpace is a part of Space-H Services.