[meteorite-list] Spirit Finishes Pre-Winter Drives

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri, 12 Feb 2010 13:00:21 -0800 (PST)
Message-ID: <201002122100.o1CL0Lm5005445_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2010-045

Spirit Finishes Pre-Winter Drives
Jet Propulsion Laboratory
February 11, 2010

NASA's Mars Exploration Rover Spirit is now parked for the winter. The
rover team is commanding Spirit this week to make additional
preparations for the Mars southern hemisphere winter season. The team
does not plan further motion of the wheels until spring comes to
Spirit's location beside the western edge of a low plateau called Home
Plate.

On Sol 2169 (Feb. 8, 2010), the rover's last drive before winter changed
the angles of its suspension system, but it did not produce a hoped-for
improvement to the overall tilt of the solar array for catching winter
sunshine. Drives since Sol 2145 (Jan. 15, 2010) moved Spirit 34
centimeters (13 inches) south-southeastward. However, a counterclockwise
yawing of the rover during the drives prevented it from reducing its
southerly tilt.

Spirit will spend the coming winter tilted 9 degrees toward the south,
an unfavorable attitude for the solar panels to catch rays from the sun
in the northern sky. Spirit's parking positions for its previous three
Martian winters tilted northward. Engineers anticipate that, due to the
unfavorable tilt for this fourth winter, Spirit will be out of
communication with Earth for several months.

Spirit may enter a low-power hibernation mode within a few weeks,
shutting down almost all functions except keeping a master clock running
and checking its power status periodically until it has enough power to
reawaken. It may go in and out of this mode a few times at the beginning
and at the end of an extended hibernation period.

This week the rover team is uploading schedules to Spirit for when to
communicate with Earth or with the orbiting Mars Odyssey during the rest
of this year and into 2011. Spirit will use these schedules whenever it
has adequate power to wake up. Spirit will take a set of "before" images
of surroundings from the parked position this week, for comparison with
images in the Martian spring to study effects of wind. Images toward the
south will also aid preparations for possible future drives, although,
with only four of its six wheels still working, the rover is not
expected to move farther than short repositioning drives. Other
preparations for winter will include putting the robotic arm into a
position for studies of atmospheric composition when power is available
and changing the stow positions of the high-gain antenna and panoramic
camera to minimize shadowing of the solar panels.

Spirit is more than six years into a mission originally planned for
three months on Mars. Its twin, Opportunity, is exploring an area
halfway around the planet and closer to the equator, where that rover
does not need to park for the winter.

Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster at jpl.nasa.gov

2010-045
Received on Fri 12 Feb 2010 04:00:21 PM PST