This story was updated at 5:00 p.m. EST
After six
weeks of waiting out globe-engulfing dust storms, NASA's Mars Exploration
Rovers have resumed driving across the planet's surface.
With the
improved energy supplies, mission managers said Spirit and Opportunity are back
on schedule to do
science. During the storm, both rovers stood still and cut back normal
communication to conserve energy.
"Weather
and power conditions continue to improve, although very slowly for both
rovers," said John Callas, project manager for the mission at NASA's Jet
Propulsion Laboratory in Pasadena, Calif.
Despite the
energetic progress, the rovers aren't out
of danger yet. Dust that was lifted into the air "could take months"
to clear, said rover Project Scientist Bruce Banerdt. "There is a lot of
very fine material suspended high in the atmosphere," Banerdt said, noting
that the dust is accumulating on the rovers' energy-gathering solar panels.
Rover panoramic camera scientists said that the sun was nearly blotted out during the peak of the dust storm, as shown in
an image released today.
Although 99 percent of direct sunlight never made it to the rovers' solar panels, indirect sunlight glowing through the dust charged the rovers'
batteries enough to warm and protect delicate circuits from snapping.
Scientific
schedule
Now that
the storm is clearing, rover scientists are eager to roll Opportunity inside
the 2,400-foot-wide (730-meter-wide) Victoria Crater
and scope out its inner slope.
"This
is a magnificent crater with a lot of exposed bedrocks and walls showing
geologic detail with extensive layering that makes the team geologist very
happy," said Thanasis Economou, a senior scientist at Chicago's Enrico
Fermi Institute. "What you can see is amazing."
Opportunity's descent was delayed when the
dust storms began in mid-June. Mission managers, however, are still
deciding when to continue the much-anticipated crater dive.
Meanwhile,
Spirit's microscopic imager has been sprayed with dust from the storm to
slightly reduce its image quality. The team is experimenting with ways to try
dislodging dust on the lens and is planning to drive the rover onto a platform
informally named "Home Plate."
Looking
up
Both rovers
will start a new atmosphere-monitoring project using their Alpha Particle X-ray
Spectrometer (APXS) instruments, which engineers initially designed to examine
rocks and boulders on the surface. The APXS instruments will measure argon,
which the orbiting Mars Odyssey spacecraft discovered is responsible for mixing
the thin martian air between summer and winter.
Scientists
hope the rover's finer measurements from the ground will reveal some
climatological secrets of Mars.
"It
gives you a way of inferring aspects of the Martian circulation that you can't
observe at all with any other instrument that's out there," said Ray Pierrehumbert,
a planetary geophysicist at the University of Chicago in Illinois.
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