PART 1 -- Exploring, Evaluating, and Mining
Nonterrestrial Resources
Richard E. Gertsch
The earliest writings on space industrialization recognized
the
need for materials to feed factories in orbit (O'Neill 1974; Johnson and Holbrow
1977; Billingham,
Gilbreath, and O'Leary 1979). Transportation economics dictated (and still dictate)
that the Earth
cannot be the source of these materials. Recent writings (such as O'Leary 1983)
have backed away
from the concept of many large factories in orbit and concentrated instead on
small, specific projects
involving nonterrestrial materials.
Early large-scale thinking indicated that space manufacturing
was economically favorable and could
be a source of exciting new technologies. Space as a source of new wealth inspired
dreams of capturing
large asteroids, building Lagrangian industrial parks, and supplying cheap,
plentiful products to a needy
Earth. But industrial space parks represent a mature system and beg the question
of how we get there.
Given the expense of current space missions and our lack 9f deep space experience,
moving directly to a
mature system is not practical. A more circumSpect scenario is needed. The early
writers were not wrong,
just premature; the question is, "What can we do tomorrow?"
While that question has not yet been answered, it has at least
been formulated. One approach that
has been suggested is to extract liquid oxygen from lunar materials and supply
it to low Earth orbit
(LOX to LEO) for use as spacecraft propellant (Davis 1983). Even if the idea
never matures, it is an
excellent starting point. In its mining and manufacturing activities, the project
is modest, although it
requires a significant jump in space transportation capability. It's specific,
and it promises a return
on investment. Much of this workshop's attention was focused on the LOX-to-LEO
idea, although
participants also recommended beginning an asteroid exploration program. The
authors of the
papers that follow concentrate on key practical problems in finding and exploiting
the necessary raw
materials, and they recommend solutions to these problems.
The members of our workshop group also considered some more
advanced projects, such as a larger
scale lunar base, capable of providing additional products. But, in the advanced
scenarios, the group
felt hampered by lack of problem definition. There was simply too little direction
on types
of products and project size. Terrestrial mining operations are driven by the
market price of the product.
Without such basic definitions, the group decided to concentrate on the LOX-to-LEO
plan.
We discussed missions to retrieve material from asteroids that
pass close to or cross the Earth's orbit.
Although the difficulties in an asteroid mission appeared to be greater
than those in a lunar mission,
there also seemed to be no compelling reason why a modest mission could not
qualify as a beginning
effort in space resource exploitation. The sheer diversity of materials available
from a single, small, Earth-
approaching asteroid, along with the low A V required to retrieve such materials,
warrants their consideration.
The right asteroid could, in theory, supply most of the materials for a semi-closed
space habitat, in addition
to filling other industrial needs.
Comparing the LOX-to-LEO plan to the asteroid mission
pointed up a basic dichotomy
within our workshop group-a dichotomy of opinion as to what that first mission
should be.
Those experienced in the high-risk terrestrial mineral extraction business tend
to favor the
modest, specific LOX-to-LEO-type mission, arguing that risk should be
minimized while we
learn from and build on the first-small- lunar mining project. Those experienced
in the basic
sciences tend to favor the asteroid retrieval mission, arguing that the orbital
mechanics to reach
some asteroids are favorable and that the array of asteroidal materials is impressive.
They admit,
however, a current lack of information on specific asteroid targets, which must
be addressed.
Another good example of the Moon-asteroid dichotomy is the
question of the time value of money.
The scientists in our group rightly pointed out that the transportation
costs to the Moon and to
the near-Earth asteroids are nearly equal, because the needed energy expenditures
are similar.
The mining industry representatives were concerned with the large time difference
between the
two missions; the round trip to the Moon takes about 2 weeks; to an asteroid,
about 2 years.
A lunar mine could begin producing almost immediately; an asteroid mine could
not. This difference
in time- to-production means that the capital amortization
costs for a lunar mine would be much lower
than those for an asteroidal mine. The time factor is a real and significant
cost that must be repaid before
a return on investment is realized. We note that an asteroid materials "pipeline"
would overcome this
problem, but such a pipeline is a part of a mature system, not of a startup
enterprise. On the other hand,
there may be compelling noneconomic reasons to ignore the time value of money
(or other factors).
Mineral operations on the Earth are occasionally operated at a loss in order
to attain energy independence
(Japan) or tqobtain hard currency (Chile).
While our report on space mining and resource extraction favors
the LOX-to-LEO or a similar lunar
mission, we recommend that asteroid resource research be continued.
Lunar exploitation may
lead to exploitation of the asteroids from a cislunar staging area, using space
manufacturing
equipment and methods developed on the Moon. The Moon would then become a learning
ground as well as a materials source. Or subsequent study of the lunar mining
plan may show
that asteroid retrieval is a superior mission, because particular resources
are needed or a very favorable
asteroid is found. In any case, projects like Earth-based asteroid watches and
sample retrieval missions
are justifiable on scientific grounds and are being included in NASA advanced
planning scenarios. The
data to be collected from these projects must be reviewed to ensure that they
are appropriate to support
mining enterprises.