Mars Rover Spirit Studies Geology
While Preparing for Martian Winter

NASA’s Mars Exploration Rover Spirit recorded this view while approaching the northwestern edge of "Home Plate." With Martian winter closing in, engineers and scientists working with NASA’s Mars Exploration Rover Spirit decided to play it safe for the time being rather than attempt to visit the far side of Home Plate in search of rock layers that might show evidence of a past watery environment. This feature has been one of the major milestones of the mission. Though it’s conceivable that rock layers might be exposed on the opposite side, sunlight is diminishing on the rover’s solar panels and team members chose not to travel in a counterclockwise direction that would take the rover to the west and south slopes of the plateau. Slopes in that direction are hidden from view and team members chose, following a long, thorough discussion, to have the rover travel clockwise and remain on north-facing slopes rather than risk sending the rover deeper into unknown terrain.
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Photo by NASA/JPL-Caltech/NMMNH

(NASA/JPL) Spirit successfully completed four Martian days, or sols, of driving clockwise around the rim of "Home Plate" toward the south and east. The rover is currently spending three sols studying a rock target called "Fuzzy Smith" using three instruments on the robotic arm: the microscopic imager, Mössbauer spectrometer, and alpha particle X-ray spectrometer. Spirit is currently racing against the clock to complete as many projects and observations as possible before the Martian season of winter arrives, in which solar energy is scarce. The NASA team is currently mapping out a route to McCool Hill which is the best location to wait out the winter.

During the coming week, Spirit will communicate with Earth in UHF-only mode while NASA’s Mars Reconnaissance Orbiter arrives at the red planet.

Sol-by-sol summaries:

Sol 763 (Feb. 25, 2006): Spirit completed scientific studies of a rock target called "Crawfords."

Sol 764: Spirit drove 22.7 meters (74.4 feet) and acquired post-drive images with the panoramic and navigation cameras.

Sol 765: Spirit acquired panoramic camera images of a transit of the Martian moon, Phobos, and recharged the batteries for the next day of driving.

Sol 766: Spirit drove 37 meters (121 feet), acquired post-drive images, and conducted atmospheric observations.

Sol 767: Spirit drove 29 meters (95 feet), acquired post-drive images, and conducted atmospheric observations.

Sol 768: Spirit drove 14.26 meters (47 feet) to the top of white outcrops on the rim of "Home Plate."

Sol 769: Plans are for Spirit to began a 3-day campaign of scientific observations on a rock target dubbed "Al ‘Fuzzy’ Smith," using instruments on the rover’s robotic arm, including the microscopic imager, alpha particle X-ray spectrometer, and Mössbauer spectrometer.

Sol 770 (March 3, 2006): Plans are for Spirit to continue scientific studies of "Al ‘Fuzzy’ Smith."

As of sol 770 (March 3, 2006), Spirit’s total odometry was 6,693 meters (4.16 miles).

Click Here for a previous update from Mars Spacecraft "Spirit" as it arrived at "Home Plate"

Mars Rover Opportunity Continues
to Skirt Erebus Crater

This image mosaic from the microscopic imager aboard NASA’s Mars Exploration Rover Opportunity shows detailed structure of a small fin-like structure dubbed "Roosevelt," which sticks out from the outcrop pavement at the edge of "Erebus Crater." Roosevelt lines a fracture in the local pavement and scientists hypothesize that it is a fracture fill, formed by water that percolated through the fracture. This would mean the feature is younger than surrounding rocks and, therefore, might provide evidence of water that was present some time after the formation of Meridiani Planum sedimentary rocks.

Photo by NASA/JPL/Cornell/USGS

(NASA/JPL) After completing work at the outcrop called "Olympia," Opportunity proceeded around the western edge of "Erebus Crater" toward an outcrop dubbed "Payson." After performing diagnostic tests on Martian day, or sol, 735 (Feb. 17, 2006), the rover team decided to increase rotor resistance from 65 ohms to 80 ohms for stowing and unstowing the robotic arm. Opportunity successfully stowed and unstowed the arm on both sols 740 and 741. As long as the robotic arm remains in calibration, the higher resistance value provides no additional risk.

Sol-by-sol summaries:

Sol 735 (Feb. 17, 2006): Opportunity conducted diagnostic activities on its robotic arm, making small movements of the shoulder joint with rotor resistance set at 75 ohms. If the arm were to fault out during any of the motions, the rover would clear the fault and re-set the resistance first to 80 ohms, and then to 85 ohms. However, the arm completed all motions successfully with rotor resistance set at 75 ohms.

Sol 736: The rover team attempted for a second time to send instructions via X-band frequencies for a drive to a target called "Zane Grey," but a Deep Space Network transmitter was down. The team did receive data from Opportunity over the same communications link.

Sol 737: Rover planners sent instructions to Opportunity for the second two days of the original three-day plan. Opportunity made atmospheric observations and measurements of the intensity of astronomical objects.

Sol 738: Opportunity continued to make remote atmospheric observations and photometric measurements.

Sol 739: Opportunity completed planned photometric measurements.

Sol 740: Opportunity began the planned drive to Zane Grey, stowing and unstowing the robotic arm with rotor resistance set at 80 ohms on the shoulder joint that controls compass direction. The rover halted after moving 21 centimeters (8 inches) when the right middle wheel reached the maximum current allowed. Motor currents on the other wheels remained nominal. Rover planners reduced the current limits after leaving "Purgatory Dune" to help prevent another imbedding event.

Sol 741: Opportunity drove 34.5 meters (113 feet) closer to the Payson outcrop after rover drivers set the current limits back to nominal values. Motor currents at the start of the drive were a bit higher than normal but dropped closer to normal values as the drive progressed.

Sol 742: Science team members planned to have Opportunity drive about 40 meters (130 feet) closer to "Payson" and acquire images from a distance of 20 meters (65 feet) over the weekend.

As of sol 742 (Feb. 24, 2006), Opportunity’s total odometry was 6553.93 meters (4.07 miles).

Click Here for a previous update from Mars Spacecraft "Opportunity" at "Olympia"