Transportation Economics of Extraterrestrial Resource Utilization
By Andrew Hall Cutler and Mari Leilani Hughes
It is assumed that the utilization of space shuttle
external tanks as an extraterrestrial resource is
economical, as it would be ridiculous to discuss the
use of lunar or asteroidal resources if this were not
true.
[Gramlich
Disagrees --
`Shuttle is Uneconomical']
Due to the restricted composition and limited nature of
this resource, the exploitation of lunar and asteroidal
resources is worthy of consideration. Several conclusions
can be drawn from a consideration of the economics of
mining the moon and asteroids. It is shown that production
of lunar oxygen or steel for use in LEO is economically
justified in the near future, and is superior to the use
of asteroidal resources. Production of lunar hydrogen,
if feasible, is not desirable from an economic standpoint
until a lunar oxygen producing facility is on line and
delivering oxygen to LEO. In determining economic
feasibility high mass payback ratios are not particularly
important. Low initial capital investment is more
important. Thus steel for uses such as SDI is a more
economical product than oxygen for propulsive or other
uses. It is found that optimizing and comparing
selected physical parameters such a delta V or
Isp does not in general lead to the most
economical system. Two major questions are identified
which have a major impact on extraterrestrial materials
utilization economics. These are minimum achievable
ratios of dry mass to loaded mass for the transport
vehicles, and the ability to manufacture at the mine
mouth. Dry to fully loaded vehicle mass ratios must
be less than 6% or so if there is any hope for economical
transportation. The ability to perform manufacturing at
the mine mouth is probably dependent on human presence
for repair.
Introduction
{Typing in much more of the Cutler and Hughes paper
is not needed for this example --
Wayne Gramlich}