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)