Mars Exploration Rovers Update - March 3, 2006

SPIRIT UPDATE: Spirit Studies Geology While Preparing for Martian

  • sol 763-770, Mar 03, 2006:

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, Moessbauer spectrometer, and alpha particle X-ray

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

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

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 Moessbauer 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).

OPPORTUNITY UPDATE: Opportunity Continues to Skirt Erebus Crater - sol
735-743, Feb 24, 2006:

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
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
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
via X-band frequencies for a drive to a target called “Zane Grey,” but
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
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
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).