Inside a 'Clean Room': NASA Puts Mars Rover Together
The bodies of the flight model (left) and engineering model (right) of Curiosity. The flight model will be the rover launched into space, with the engineering model serving as a back-up.
Credit: Andrea Thompson

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.