[cdn-nucl-l] nuke power or not: " NASA Weighs Power-Source Options for Mars Rover "

["Jaro" <jaro-10kbq@sympatico.ca>]

http://www.space.com/spacenews/businessmonday_061016.html
NASA Weighs Power-Source Options for Mars Rover
Oct 16 2006
By Brian Berger, Staff Writer

NASA expects to decide by the end of the year whether to use conventional
solar arrays or a nuclear battery to power the 2009 Mars Science Laboratory
rover.

NASA clearly would prefer to use a so-called multi-mission radioisotope
thermoelectric generator, or MMRTG, a device that converts heat from
decaying Plutonium-238 into electricity.
<SNIP>

Mark Dahl, NASA’s Mars Science Laboratory program executive, said the agency
could use conventional solar arrays for the duration of the rover’s nominal
687-day mission, which spans one martian year. But Dahl said a solar-powered
rover would be more limited in where it could land. Because of sunlight
considerations, Dahl said, NASA would have to pick a landing spot within 15
degrees north or south of Mars’ equator. A nuclear-powered rover, on the
other hand, could operate anywhere within 60 degrees north or south of the
equator.
<SNIP>

In addition to giving NASA a wider choice of landing sites, a
nuclear-powered rover could operate for far longer than a similar vehicle
powered by solar arrays. The MMRTG that NASA is designing with the U.S.
Department of Energy for the Mars Science Laboratory, sized to generate
110-120 watts of power at the time of landing, could still be cranking out
90 watts of useable electricity 14 years later, according to Dahl. Solar
arrays, in contrast, degrade much faster and would not be expected to last
more than a few years once exposed to the dust and radiation on Mars.

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