Houston We Have a Problem - I'm Stuck In The Mud

NASA's Mars Exploration Rover, Spirit, has been slipping around in soft osil for a few days in an attempt to drive the martian rover. The wheels are now sunk halfway into the ground, making every action NASA makes to free the rover from the loose soil, critical.

The rover team of engineers and scientists has suspended driving Spirit temporarily while studying the ground around the rover and planning simulation tests of driving options with a test rover at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

"Spirit is in a very difficult situation," JPL's John Callas, project manager for Spirit and its twin rover, Opportunity, said Monday. "We are proceeding methodically and cautiously. It may be weeks before we try moving Spirit again. Meanwhile, we are using Spirit's scientific instruments to learn more about the physical properties of the soil that is giving us trouble."

Today makes the 1900th Martian Day that the Spirit has been on Mars. Both rovers, Spirit and Opportunity have operated on the Mars surface five years longer than originally planned.

To make matters worse for the stuck Spirit rover, the rover only has five operational wheels out of the six. One of the wheels had stopped operating very early in the mission.

In the past week, the digging-in of Spirit's wheels has raised concerns that the rover's belly pan could now be low enough to contact rocks underneath the chassis, which would make getting out of the situation more difficult. The right-front wheel on Spirit stopped working three years ago. Driving with just five powered wheels while dragging or pushing an immobile wheel adds to the challenge of the situation.

Favorably, three times in the past month, wind has removed some of the dust accumulated on Spirit's solar panels. This increases the rover's capability for generating electricity. "The improved power situation buys us time," Callas said. "We will use that time to plan the next steps carefully. We know that dust storms could return at any time, although the skies are currently clear."

Behavioral problems that Spirit exhibited in early April -- episodes of amnesia, computer resets and failure to wake for communications sessions -- have not recurred in the past three weeks, though investigations have yet to diagnose the root causes.