Two University of Arizona planetary scientists will testify this week before
the House Subcommittee on Space and Aeronautics. The subcommittee is
studying the feasibility of lunar-based scientific and commercial
activities.
UA Professors Timothy D. Swindle and John S. Lewis are among five scientists
who will testify in Washington, D.C. on April 1 during the subcommittee
hearing on “Lunar Science & Resources: Future Options.”
The subcommittee wants to learn about the problems and benefits associated
with an extended, or possibly permanent, human presence for scientific
exploration and mining, according to information Lewis and Swindle received
from Rep. Dana Rohrabacher (R-Calif.). Rohrabacher is chairman of the
subcommittee, which is part of the House Committee on Science.
The 1 p.m. session will be webcast at http://www.house.gov/science. Click on
the bar at the left, “webcast.” The webcast starts when the chairman hammers
the gavel, which is usually 5 or 10 minutes after the hour.
Swindle, a cosmochemist, specializes in measuring noble gases in
extraterrestrial materials, such as lunar samples and meteorites. His work
focuses on developing a better understanding of the solar system’s
chronology. He’s been asked to explain how material from the moon can
provide an insight into the Earth’s early history.
“Studying the moon is a good way to discover more about the early history of
Earth, and perhaps even how life formed on Earth,” Swindle said. “If you
have people on the moon, you have access to lots of material and can learn
much faster.”
The subcommittee also asked Swindle to testify about the feasibility of
mining helium-3. Helium-3 could be used to fuel fusion reactors on Earth.
In the past, Swindle has estimated how much helium might be found on the
moon. “I’ll point out what we would need to learn to make those estimates
more reliable,” he said. Swindle also noted that several technical problems
must be solved before helium mining will become economically feasible.
Lewis, a cosmochemist and noted authority on material and energy resources
of near-Earth space, will discuss where water is found on the moon and how
it could be exploited for use at a lunar base.
“We could take ice from the lunar poles for use as a propellant,” Lewis
said. “But ice from the lunar poles is a very poor gift. It’s stored under
abysmally difficult conditions, as permafrost at 100 degrees above absolute
zero. Ice at that temperature has roughly the strength of steel. At the same
time the metal excavating equipment needed to retrieve it would be brittle
as glass.”
Still, if the technical challenges can be met, water is one of the lunar
resources vital to supporting human activities, Lewis added.
“We can use water to manufacture propellants for hopping about the surface
of the moon,” he said. It also can be used to produce liquid oxygen for life
support and for fueling return trips to Earth.
Loose regolith (dirt and rocks) is a useful byproduct of mining, Lewis said.
It could be piled up to create radiation shielding.
The biggest problem, however, is that lunar ice is in the wrong place.
Future bases are likely to be close to the equator because it is easier to
land there, Lewis said. “So much of the lunar water mined as propellant
would have to be used just to make the long trip between the ice caps and
the lunar base,” he said.
Dan Lester of the University of Texas, Donald Campbell of Cornell
University, and Paul Spudis of the Johns Hopkins University Applied Physics
Laboratory in Baltimore, Md, will also testify at the hearing.
