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
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
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
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
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
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,
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
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
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
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
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
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
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
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
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
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
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
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
- Construct and demonstrate a totally closed environment
- Evaluate nonterrestrial resources for SSP construction
- Investigate the use of teleoperated robots in NEO-mining
and space construction
- Search for NEO's and design a program to assay their
- Advance technology readiness level of mass driver
and high performance solar sail technology and
- 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,