Since May 6, the Mars rover Spirit has been trapped in Troy, a patch of loosely bound soil on the surface of the Red Planet. Engineers at the Jet Propulsion Laboratory (JPL), in Pasadena, California, who manage the robot, say that, over the past few months, a number of drive tests has been conducted with two test rovers in a sandbox at the lab that mimics the exact conditions in which Spirit is trapped. Now, they are ready to move to the next stage, in which they will conduct an operational readiness test for the MER component.

This means that they will essentially exit the building, and then begin to maneuver the test rover based solely on the video feedback they receive from it. This is nothing but a test for the real action, which will see them trying to move Spirit from millions of miles away. When they contact the rover, they will experience a ten-minute delay between the time when the signal is emitted from the Earth and the time it actually reaches Mars. The mission managers need to take this into account. Otherwise, they only risk making things worse.

“We conducted this round of testing under more flight-like conditions to test the team's ability to make very complex extraction driving decisions using only the data sent back from the rover,” JPL Mars Exploration Rover (MER) Project Manager John Callas explains. The tests began on October 12, and went on for about five days. In addition to taking care of the test rover, the team also had to take care of Spirit and its twin, Opportunity. The second exploration robot is currently heading for the Endeavor crater, having already reached the ten-mile marker on the planet a few months ago.

Later this month, an independent panel will review the options JPL has elaborated for removing Spirit out of Troy. The panel will also take into account the results the team has obtained from the operational readiness test, and will then make a decision on the appropriate course of action. If all goes according to plan, commands ordering Spirit to move for the first time in five months could be issued in mid-November, the JPL experts add.