FYI,

"NASA Eyes Nuclear Power for Moon Base"
Space.com
http://www.space.com/businesstechnology/080917-tw-fission-moon.html

: Nuclear power could make a comeback beyond Earth if NASA goes
: forward with a proposed a fission reactor in its future moon base.

: A fission-powered system could generate up to 40 kilowatts and give
: any lunar outpost enough power to supply eight houses on Earth.
: More importantly, astronauts will require a reliable and steady
: energy source on the moon and Mars.

: "The problem with power on the moon is that, depending on where
: you're located, you may have 14 days of darkness," said Lee Mason,
: an engineer at NASA's Glenn Research Center in Cleveland, Ohio, who
: heads the project. "We think nuclear offers some advantages there
: in terms of a continuous power source in sun or darkness."

: Engineers envision a nuclear reactor buried under the surface of
: the moon so that lunar soil, known as regolith, can act as
: shielding against the reactor's radiation. Power converters would
: sit atop a tower jutting above the surface, changing the reactor's
: heat energy into electrical energy for astronauts to use.

: The tower would also boast two 50-foot (15-meter) panels made of
: polymer composite material that could give off excess heat from the
: nuclear reactor.

: Far-flung robotic missions, such as the Cassini orbiter currently
: orbiting Saturn, have relied on a different nuclear technology,
: Radioisotope Thermoelectric Generators (RTG), which draws on the
: energy from the natural decay of radioactive plutonium. Current
: RTGs produce roughly 100 watts of electricity, in comparison to
: tens of thousands of watts produced by nuclear fission reactors
: that split uranium atoms.

: NASA previously launched just one nuclear reactor into space in
: 1965, but the experimental SNAP-10A reactor shut down after just
: 43 days of operation. Nuclear power made a brief reappearance in
: the Jupiter Icy Moons Orbiter (JIMO) proposal, but the mission was
: scrapped in 2005 due to budget constraints.

: "JIMO was a little ahead of its time, a very ambitious program, and
: it didn't just quite fit in with the budget projections," Mason
: told SPACE.com.

: Now the moon base proposal offers a new possibility, but Mason's
: NASA Glenn team must first decide which power converter engine to
: use for any nuclear reactor.

: One design, a piston Stirling design from Sunpower Inc., of Athens,
: Ohio, uses two back-to-back piston engines that cancel out each
: other's mechanical vibration. The second design by Barber Nichols
: Inc. of Arvada, Colo., relies on a closed Brayton cycle engine that
: has a rotary system not unlike jet turbine engines. Both power
: converters can produce 12 kilowatts, or roughly 40 kilowatts in a
: pack of four.

: NASA engineers hope to test the efficiency of power converters
: without the nuclear reactor in 2012 or 2013. A non-nuclear reactor
: simulator would provide the heat source for the tech demonstration
: on Earth, courtesy of NASA's Marshall Space Flight Center in
: Huntsville, Ala.

: The space agency continues to ponder non-nuclear options such as
: solar power for a future lunar base. If NASA does use a nuclear
: reactor, it will resemble reactor technology that the U.S.
: Department of Energy (DOE) "has operated for many years," said John
: Warren, executive head of NASA's Space Power Systems Program in
: Washington, D.C.

: Mason said that the project should finish on schedule if it
: continues receiving the $10 million funding shared between NASA and
: the DOE.

: "We would like to design a system that can last eight years without
: any maintenance whatsoever," Mason said. "The technology is there
: to achieve that."

Mark Reiff