In the Payload Hazardous Servicing Facility, an overhead crane lowers the Mars Exploration Rover (MER) aeroshell toward a rotation stand.

The Mars Exploration Rover-2 is moved to a workstand in the Payload Hazardous Servicing Facility.

Rover team members with rover.

Two generations of Rovers.

One of two Mars Exploration Rovers sits inside its cruise stage waitingto undergo environmental testing at NASA's Jet PropulsionLaboratory.

Members of the Mars Exploration Rovers Assembly, Test and Launch Operations team gather around Rover 2 and its predecessor, a flight spare of the P...

Rover 2 is driven over staggered ramps to test the suspension's range of motion.

Environmental testing

NASA's twin robot geologists, the Mars Exploration Rovers, will launch toward Mars in 2003 in search of answers about the history of water on Mars....

Artist's concept of controlling the rover from Earth, scientists drive the rover along Mars' surface inspecting geological features.

An artist's concept portrays a NASA Mars Exploration Rover on the surface of Mars.

Stowed in the nose cone of this Delta II rocket, the Mars Exploration Rover blasts off from the Kennedy Space Center in Florida. It's destination: ...

NASA's twin robot geologists, the Mars Exploration Rovers, will launch toward Mars in 2003 in search of answers about the history of water on Mars.

Protected by large airbags, the lander falls away from the parachute, landing safely on Mars.

The nose cone of the rocket separates during the launch phase and the Mars Exploration Rover is sent on a seven-month journey to Mars.

The aeroshell protects the rover from fiery temperatures as it enters the Martian atmosphere in January, 2004.

After bouncing to a stop, the lander's petals unfold and the Mars Exploration Rover drives onto the surface of Mars.

With the parachute deployed, three retrorockets fire their engines, suspending the lander 30 - 50 feet above the Martian surface.

Artist's concept of rover using the rock abrasion tool (RAT) on the robotic arm grinds away the rock's surface, allowing scientific instruments to ...

In this photo, engineers are preparing the rover for vibration testing to ensure that it can undergo the rigors of launch and entry into the martia...

The cruise stage provides power, communication and propulsion for the rover and lander within its cocoon made up of the heatshield and backshell fo...

Mars Exploration Rover parachute deployment testing in the world's largest wind tunnel at NASA's Ames Research Center, Moffet Field, Calif.

Rover 1 sits atop the deployed lander with its solar arrays and wheels stowed.

Rover 2 equipment deck, with solar arrays partially deployed, in JPL's Spacecraft Assembly Facility's cleanroom.

A "Martian mechanic" checks beneath the completely deployed Rover 1 lander. Atop the lander is Rover 1 with its wheels and solar arrays in ...