If you think the Mars rovers are interesting, wait until you see a
mini-van clambering over the planet’s red rocks and dusty lake beds.

The two golf-cart size rovers that are mesmerizing the country now are
preparing the way for a 2009 mission to Mars called the Mars Scientific
Laboratory, says William Hiscock, head of the physics department and
director of the Montana Space Grant Consortium based at Montana State
University-Bozeman. The 2009 mission will involve a rover, too, but that
vehicle will be the size of a mini-van.

Lest anyone picture adventurous soccer parents doubling as astronauts,
Hiscock said the upcoming rover, like the Spirit and Opportunity rovers,
will be remotely controlled. It will be nuclear powered instead of solar
powered.

Nuclear power is a good thing, because it means the rover won’t be
disabled by dust covering the power source, Hiscock said. The current
rovers are expected to run 90 days before they’re done in by conditions
like dust or extreme temperature changes.

"Dust builds up on solar panels, decreasing the light getting in. The
power fades away because of it," Hiscock explained.

Roving around Mars is like being 100,000 feet above sea level on Earth,
Hiscock added. So when day turns into night, temperatures can drop up to
200 degrees, only to surge again the next day.

"That puts a lot of thermal stress on electronics and wiring," Hiscock
said. "Eventually probably, something just breaks after going through so
many cycles."

The Sojourner rover that landed on Mars in 1997 and still sets on the
planet was disabled by dust and extreme temperatures, Hiscock said. It
weighed 23 pounds, which means the Spirit and Opportunity are almost big
enough to roll over it. The two rovers each weigh about 400 pounds.

Michelle Larson, deputy director of the Montana Space Grant Consortium,
said the larger size of the 2009 rover will give it the ability to
survive longer than current and past rovers.

"Therefore, science experiments performed on the 2009 rover will be able
to make long duration measurements to see how the environment changes in
time," Larson said. "The intent is to have the science instruments on the
rover operating for an entire Martian year (which is approximately two
Earth years)."

The 2009 mission will investigate the capacity of the Mars environment to
sustain life, Larson said. Among other things, the mission will look for
organic carbon compounds and features that might have resulted from
biological processes. The mission will look at the geology and
geochemistry of the landing area, investigate the role of water and other
processes that may have been relevant to past living conditions. The
mission will look at the effects of cosmic and solar radiation on the
Martian surface.