ARCADIA, Calif. -- Engineers and scientists working on the NASA Mars Exploration Rover (MER) project are in the final stages of readying the twin robots for launch and picking safe and scientifically rewarding landing sites on the red planet.

The road to Mars for the MER program has not been easy. A number of technical challenges -- such as designing, testing and qualifying airbag and parachute systems, in particular -- dogged the project, requiring extra time, money and talent.