PASADENA, Calif.
— It may not look like much now, unassembled under silver tarps, but once it's completed
and launched, the Mars Science Laboratory will be the biggest, most powerful
vehicle ever sent to the red planet.
The
assembly of MSL (recently re-named
"Curiosity") here at NASA's Jet Propulsion Laboratory is moving
along slowly but surely — mission engineers are taking their time now that they
have two extra years to prepare after the mission's original 2009 launch date
was delayed
until 2011.
Once it is
completed, the rover will have a complex suite of instruments that can test the
Martian surface for signs of past potential habitability, including onboard chemistry
labs and a laser that can zap rocks to determine their composition.
There are
still a few kinks to work out, and mission planners want to make sure they
address every problem.
The rover
is "still a really big, complex thing," said Joy Crisp, a deputy
project scientist for MSL.
Clean
room and bunny suits
On the
floor of a "clean room" at JPL's Spacecraft Assembly Facility, the
metal body of the rover -- destined to be the size of a small car and weigh 2,040
pounds (925 kg) -- sits upside-down on a rack, none of its Mars-probing
instruments yet attached.
"We're
in the early stages of assembly," Crisp said.
The wheels
that will move the robot across the dusty Martian surface stand upright in
metal crates. Nearby, covered by a tarp, is the huge saucer-shaped heat shield
that will protect the craft as it plummets through the Martian atmosphere.
The
elaborate crane system that will lower the rover to the ground before flying
off and crashing is on the other side of the room, held up by a metal frame.
Men in
white "bunny suits" carefully vacuum the clean room floor to remove
any contaminating dust and slowly move an enormous overhead crane to lift and
shift parts around.
Testing,
testing
As the
spacecraft is assembled, engineers are testing out all of its components to
find any potential flaws and fix them before the rover is sent on its journey
to Mars.
The biggest
concern right now, Crisp said, is the actuators, the motors that control the
movements of the rover's wheels, mast and robotic arm. The problem is getting
the actuators to work at the cold temperatures of the region where Curiosity
will land. While the rover's landing site won't be as far north as was the
Phoenix Mars Lander's (which landed last summer in the arctic plains of Mars),
it will be further north of NASA's two rovers currently on the Martian surface,
Spirit
and Opportunity.
Curiosity
is also benefiting from the experience of its predecessors. Last summer, Phoenix had difficulty getting samples of dirt into its instruments because the dirt
would clump together. Curiosity's team is working on ways to get around
this problem should the new rover encounter sticky soil.
To prepare
for this issue, the team is testing Curiosity's instruments with more types of
soil-mimicking materials, Crisp said. They are also considering installing a
test funnel in the front of the rover where they could deposit soil samples
first and "see if it jams or goes through," Crisp said.
Another
idea is to use a device like a pipe cleaner that could clear out any clogs.
Essentially the team is looking at "things that could be added quite late
in the design," Crisp said.
Once the
design is finalized and Curiosity is fully equipped for its Martian mission, it
will be launched and eventually land at one of four sites that is yet to be
decided upon. Once the probe touches down, it will investigate the local
geology, chemistry and the potential for biology, including looking for an
answer to one of the biggest questions: "Are there organics on Mars?"
Crisp said.
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