Rover 'Vulnerable' From Low Power State
After nearly five years of yeoman service, one of NASA's Mars
rovers may be nearing its end. A dust storm on Mars has cut into
the amount of sunlight reaching the solar array on NASA's Mars
Exploration Rover Spirit, leaving the rover in a vulnerable
Spirit's solar array produced only 89 watt hours of energy
during the rover's 1,725th Martian day, which ended on November 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, CA project manager for Spirit and
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.
Another dust storm -- this one near the Northern pole of Mars --
is to blame for the loss of signal from NASA's Mars Phoenix Lander,
As ANN reported, NASA lost contact with the
five-month-old lander November 2.
Phoenix wasn't expected to survive the Martian winter, though
NASA lost the signal from the lander sooner than anticipated.