Dust storm cuts Spirit's energy supply

Spirit's solar array produced only 89 watt hours of energy during the rover's 1,725th Martian day, which ended on Nov. 9. This is the lowest output by either Spirit or its twin, Opportunity, in their nearly five years on Mars, and much less energy than Spirit needs each day. The charge level of Spirit's batteries is dropping so low, it risks triggering an automated response of the rover trying to protect itself.

"The best chance for survival for Spirit is for us to maintain sequence control of the rover, as opposed to it going into automated fault protection," said John Callas of NASA's Jet Propulsion Laboratory, Pasadena, Calif., project manager for Spirit and Opportunity.

Mission controllers are commanding Spirit to turn off some heaters, including one that protects a science instrument, the miniature thermal emission spectrometer, and take other measures to reduce energy consumption. The commands will tell Spirit not to try communicating again until Thursday. While pursuing that strategy the team also plans to listen to Spirit frequently during the next few days to detect signals the rover might send if it does go into a low-energy fault protection mode.

Mars weather forecasts suggest the dust storm may be clearing now or in the next few days. However, the dust falling from the sky onto Spirit's solar array panels also could leave a lingering reduction in the amount of electricity the rover can produce.

Credit: NASA/JPL-Caltech/Cornell.
High resolution image (1.5 MB)

The deck of NASA's Mars Exploration Rover Spirit is so dusty that the rover almost blends into the dusty background in this image assembled from frames taken by the panoramic camera (Pancam) during the period from Spirit's Sol 1,355 through Sol 1,358 (Oct. 26-29, 2007).

Dust on the solar panels reduces the amount of electrical power the rover can generate from sunlight each sol.

The vertical projection used here produces the best view of the rover deck, though it distorts the ground and antennas somewhat. The eight-pointed star shape near the front of the rover (bottom of the image) marks the location of the camera mast, which is out of view of the Pancam atop the mast.

This mosaic view in approximate true color is a composite of frames taken through the Pancam's filters centered on wavelengths of 600 nanometers, 530 nanometers and 480 nanometers.

Source: Jet Propulsion Laboratory
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