Mars
Spacecraft Spirit
Reaches "Home Plate"
 |
Hardened Lava Meets Wind on Mars
NASA’s
Mars Exploration Rover Spirit captured this
spectacular, jagged mini-landscape
on a rock called "GongGong." GongGong formed
billions of years ago in a seething, stirring mass of
molten rock. It captured bubbles of gases that
were trapped at great depth but had separated from the
main body of lava as it rose to the surface. Like taffy
being stretched and tumbled, the molten rock was deformed
as it moved across an ancient Martian landscape. The
rock then withstood billions of years of pelting by small
sand grains carried
by Martian dust storms that sometimes blanketed the planet.
The sand wore away the surface until, little by little,
the delicate strands that enclosed the bubbles of gas
were breached and the spiny texture we see today emerged.
Photo
by NASA/JPL Caltech/Cornell/USGS |
(NASA/JPL) After
several months of driving, Spirit finally reached the semicircular
geologic feature dubbed "Home Plate" in Gusev Crater.
Spirit first got a good view of Home Plate in late
August, after cresting "Husband Hill." After
that, the rover made scientific observations near the summit before commencing
an ambitious drive of 848 meters (2,782 feet, a little more than half a
mile) in 94 Martian days, or sols, to get to Home Plate.
Spirit is now studying
a rock target called "Barnhill" just below the tabletop-like
surface of Home Plate using instruments on the rover’s robotic arm. Science
team
members have begun calling Home Plate the "Burns Cliff of Gusev" because
of its layered appearance and steep slopes, which is reminiscent of, but
smaller than, "Endurance Crater," explored by Spirit’s twin,
Opportunity, on the opposite side of Mars in 2004.
Sol-by-sol summaries:
Sol 743 (Feb. 4, 2006): Spirit performed untargeted remote sensing
and drove 45.7 meters (150 feet), navigating with the guidance
of engineers.
Sol 744: Spirit completed an autonomous drive of 17.5 meters
(57.4 feet), checked its orientation, and took post-drive images
of surrounding terrain.
Sol 745: Spirit completed light remote sensing and recharged
the battery for the coming week.
Sol 746:
Spirit moved 9 meters (29.5 feet) closer to the target nicknamed "Barnhill." Following
the approach, Spirit was perched at a tilt of 27 degrees.
Sol 747:
Spirit carefully unstowed the robotic arm, continuously checking
the rover’s own tilt, which changes
when the arm is
deployed. Engineers expected a change in tilt of less 0.3 degrees;
the actual change was minus 0.048 degrees. Spirit then performed
scientific analysis as planned with the microscopic imager and
Mössbauer spectrometer.
Sol 748:
Spirit continued conducting scientific studies using the Mössbauer
instrument and began acquiring a large mosaic of images with
the panoramic camera.
Sol 749: The team proceeded with plans to have the rover change
tools to the alpha particle X-ray spectrometer, continue to acquire
panoramic images, and conduct other remote sensing.
As of sol 749 (Feb. 11, 2006), Spirit’s total odometry was 6,589
meters (4.09 miles).
Mars
Spacecraft Opportunity Finishing
Up at ‘Olympia’
 |
Opportunity’s Arm in ‘Hover-Stow’ Position
In
January 2006, NASA’s Mars Exploration Rover team adopted
a new strategy for carrying Opportunity’s robotic arm (the
instrument deployment device with its turret of four tools
at the end) when the rover is driving due to problems with
the arm’s motor caused by a broken wire. The
motor still works when given extra current, but the change
in strategy for stowing the arm results from concern that,
if the motor were to completely fail with the arm in the
original stow position, the arm could no longer be unstowed
for use.
Photo by
NASA/JPL/Cornell
|
(NASA/JPL)
Opportunity
is healthy. The rover is in the midst of a robotic-arm and
remote-sensing campaign on a feature informally named "Roosevelt." Last
week Opportunity used its microscopic imager, Mössbauer
spectrometer and alpha particle X-ray spectrometer to examine "Overgaard."
The short-term
goal is to finish studying the "Olympia" outcrop
by mid next week. The final feature that will be characterized
in this location is called "Bellemont."
Sol-by-sol summaries:
Sol 723 (Feb. 4, 2006): Finished the microscopic-imager mosaic
on Overgaard.
Sol 724: Stowed the robotic arm in the hover position. Attempted
a short drive to Roosevelt, but the drive ended early due to
suspension limits.
Sol 725: Succeeded in short drive to Roosevelt.
Sol 726:
Used alpha particle X-ray spectrometer and Mössbauer
spectrometer on a target called "Rough Rider."
Sol 727: Used the microscopic imager for an image mosaic of
Roosevelt.
Sol 728:
Continued using the Mössbauer spectrometer
on Rough Rider.
Total odometry as of sol 728 (Feb. 9, 2006): 6,509.8 meters
(4.045 miles)