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Mars Exploration Rovers Update - February 24, 2006

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Mars Exploration Rovers Update - February 24, 2006
« il: Lun 27/02/2006, 14:09 »

SPIRIT UPDATE: Spirit Races Against Time and Dwindling Sunlight - sol
758-763, Feb 24, 2006:

In a race to collect as much scientific data as possible before the
onset of Martian winter, Spirit climbed to the top of "Home Plate" and
acquired images of the surrounding terrain. Each day, Spirit logs a
reduction in the total amount of solar energy collected as the sun
lower on the planet's northern horizon.

The science team's objective is to do as much science as possible while
concentrating on a drive campaign that will move the rover to the
north-facing slopes of "McCool Hill." The team has already begun
routes to McCool, where Spirit will attempt to survive a second Martian
winter with its solar panels tilted toward the sun.

Sol-by-sol summaries:

Sol 758 (Feb. 19, 2006): Spirit conducted targeted remote sensing and
acquired 13-filter images of a target dubbed "Wilmington," as well as
mosaics of the surrounding terrain, with the panoramic camera.

Sol 759: Spirit edged closer to a rock nicknamed "James 'Cool Papa'

Sol 760: Spirit acquired images of its work area with the navigation
panoramic cameras. The rover also conducted atmospheric observations.

Sol 761: Spirit used the microscopic imager to acquire images of a rock
target called "Stars." Then the rover brushed that target with the rock
abrasion tool and examined it again with the microscopic imager after
the brushing. Spirit then began checking the mineral composition of the
Stars target with the Moessbauer spectrometer.

Sol 762 (Feb. 23): Spirit continued the Moessbauer study of Stars.
Following an overhead pass of the Odyssey orbiter, Spirit began an
analysis of Stars with the alpha particle X-ray spectrometer.
planned to have the rover continue collecting scientific data over the
weekend from another target, nicknamed "Crawfords."

As of sol 762 (Feb. 23, 2006), Spirit's total odometry was 6,589.83
meters (4.09 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).
Marco Zambianchi
ForumAstronautico Founder
Presidente Associazione ISAA