Ups And Downs for Spirit Rover
Recently, Spirit has had some very good news and some very bad news. The good news is that we just had a huge cleaning event, with high winds blowing the solar panels clean so that we are getting power levels that we haven’t seen in years!
The bad news is that this occurred as Spirit got stuck in deep, soft sand. Last week we were commanding drives of tens of meters and getting tens of millimeters of progress. Not a good situation. The extra power boost helps, but Spirit still needs to get out of the soft soil before winter sets in. We had an all-hands meeting yesterday to discuss the plan for the next few weeks. We will be doing tons of imaging and measurements on the soil surrounding the rover to figure out what its mechanical properties are, and the mock-up rover at JPL will be put into the testbed, stuck in similar piles of soil and the engineers on the team will figure out the best way to extract ourselves.
For more info, check out this NASA press release:
May 11, 2009
Mars Exploration Rover Mission Status Report
PASADENA, Calif. — The five wheels that still rotate on NASA’s Mars Exploration Rover Spirit have been slipping severely in soft soil during recent attempts to drive, sinking the wheels about halfway into the ground.
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.”
Both Spirit and Opportunity have operated more than five years longer than their originally planned missions of three months on Mars and have driven much farther than designed. The rover team has so far developed ways to cope with various symptoms of aging on both rovers.
Spirit has been driving counterclockwise from north to south around a low plateau called “Home Plate” for two months. The rover progressed 122 meters (400 feet) on that route before reaching its current position.
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.
JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA’s Science Mission Directorate, Washington.