NASA's Mars rover Opportunity has sucessfully reached out toward a Martian rock with its robotic arm, overcoming a motor glitch that prevented deployment last month.
Opportunity unstowed its instrument-laden robotic arm Tuesday, aiming the multi-jointed
appendage straight ahead towards a rock outcrop jutting from a crater at its
Meridiani Planum landing site, the mission's project manager said.
"It went
fine...we successfully put an instrument on the rock," Jim Erickson, project
manager for the Mars Exploration
Rover mission at NASA's Jet Propulsion Laboratory (JPL), told SPACE.com.
"The team did a great job but we've got more work to do."
Stalled
science
Opportunity's
robotic
arm - which carries four instruments designed to photograph, brush, grind
and determine the composition of Martian rocks - stalled in its stowed position
on Nov. 25, preventing active study of the nearby outcrop at its Erebus Crater
location. A problematic shoulder joint motor, which swings the arm out from its
stowed position tucked under the rover, appeared to be the cause.
"We were
fearful for a time that the motor may have failed permanently," said Steve
Squyres, principal investigator for the rover mission at Cornell University,
during a Dec. 12 discussion at the American Museum of Natural History in New
York City. "If that were the case, we'd never be able to use the arm again."
But on Dec.
8, rover engineers managed to move the
arm slightly. The motor glitch appears to be the result of a broken wire in one
of nine windings - or coils - inside the shoulder joint, Erickson said. By applying
a higher voltage than normal to the windings, the joint moved, he added.
"We're
developing a mode for keeping the arm out in front," Erickson said, adding that
engineers are now studying various positions in which to stow the arm and
ensure its continued use as a science tool. "We'll essentially stow it now by
putting the instrument pack up over the rover's deck."
Erickson
said more analysis and arm motor tests are planned in order to determine the
best configuration for the arm during drives.
Martian
year milestone
Like its
robotic twin Spirit,
which is currently descending Husband Hill in Mars' Gusev Crater and heading
toward a target dubbed "Home Plate," Opportunity has spent more than one
entire Martian year - about 687 Earth days, or 670 Martian sols - exploring
the red planet. Opportunity's red planet anniversary occurred on Dec. 12 and
set a new milestone for the Mars rover expedition, which had a primary mission
that originally spanned just 90 Martian days.
"I used to
think that dust on our solar arrays was going to be the limit for these rovers,
I don't think that anymore," Squyres said. "I think, instead, that something is
going to break. We have a lot of moving parts and electrical parts on these
rovers."
Squyres
added that the success of Spirit and Opportunity has changed the way he looks
at Mars.
"[Before
launch] it just seemed impossibly far away, it seemed unreachable," Squyres
said of the red planet. "Tonight, I go out knowing our rovers have been there a
whole Martian year...it's a much more familiar planet. We know the place."
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