[meteorite-list] Mars Exploration Rovers Update - December 17, 2007

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 17 Dec 2007 16:36:37 -0800 (PST)
Message-ID: <200712180036.QAA15125_at_zagami.jpl.nasa.gov>

http://marsrovers.jpl.nasa.gov/mission/status.html

SPIRIT UPDATE: Final Winter Haven Selection Near - sol 1398-1403,
December 17, 2007:

To make the most of waning sunlight during the approach of Martian
winter, Spirit's handlers have returned to "Mars time." This means their
working hours coincide with the Martian day, as they did for the first
three months after the rover landed on the red planet. Because a Martian
day is about 40 minutes longer than an Earth day, Mars time can coincide
with all hours of the day and night on Earth. The alarm might go off the
same time one day, 40 minutes later the next day, an hour and 20 minutes
later the next day, and so on.

Spirit's solar power levels continue to drop, with solar array energies
recently ranging from 293 watt-hours to 254 watt-hours, depending on the
vehicle's orientation relative to the Sun. (One hundred watt-hours is
the amount of energy needed to light a 100-watt bulb for one hour.)

All members of the rover science team -- drivers, engineers, and
scientists -- are evaluating data to select a place where the rover will
attempt to survive another Martian winter, focusing on areas that will
tilt the rover's solar panels to the north more than 25 degrees. They
will select a final location from a narrowed list of choices based on
proximity to the rover's current position and the characteristics of the
terrain, with an eye for accessibility as well as continued exploration
in the spring.

Spirit reached the northern edge of "Home Plate" after driving 13.24
meters (43.44 feet) on Martian day, or sol, 1397 (Dec. 8, 2007). Three
Martian days later, on sol 1400 (Dec. 11, 2007), Spirit finished
collecting reconnaissance images of the northern exposure of the
elevated plateau.

During the past week, rover planners got a special visit from two
Tuskegee Airmen, the first black pilots to serve in the U.S. military.
The pilots shared stories about serving in World War II while learning
about rover operations.

Sol-by-sol summary:

In addition to receiving morning instructions directly from Earth via
the high-gain antenna, sending evening data to Earth at UHF frequencies
via the Odyssey orbiter, and measuring atmospheric dust levels with the
panoramic camera, Spirit completed the following activities:

Sol 1398 (Dec. 9, 2007): Spirit drove 6.5 meters (21.3 feet) in a path
nearly parallel to the northern edge of Home Plate. The rover acquired
post-drive images with the hazard avoidance cameras and a mosaic of
images with the navigation camera.

Sol 1399: Spirit drove 7.19 meters (23.6 feet) toward a small promontory
to acquire images of the slopes below. The rover acquired post-drive
images with the hazard avoidance cameras and a mosaic of images with the
navigation camera. The following morning, Spirit acquired a series of
navigation camera images to complete a 360-degree view of the rover's
location after completing the drive.

Sol 1400: Spirit nudged 0.75 meter (2.5 feet) closer to the edge of Home
Plate for a better view of what lay below. The rover acquired post-drive
images with the hazard avoidance cameras and a mosaic of images with the
navigation camera.

Sol 1401: Spirit took a break from driving and acquired images with the
panoramic camera before turning around to back down the steep slope
where the rover will spend the winter. After turning, the rover's solar
arrays blocked the view of the slope by cameras on the rover mast
assembly. Following the maneuver, Spirit acquired two image mosaics with
the panoramic camera.

Sol 1402: Spirit acquired a pre-drive image of a pointy rock known as
"General B.O. Davis" before backing up 2.5 meters (8.2 feet) and turning
180 degrees. The rover acquired post-drive images using the hazard
avoidance cameras and a mosaic of images using the navigation camera.
The following morning, Spirit monitored dust on the panoramic camera
mast assembly and completed a systematic ground survey and a survey of
rock clasts with the panoramic camera.

Sol 1403 (Dec. 14, 2007): Plans called for Spirit to approach the edge
of Home Plate backward and acquire post-drive images with the hazard
avoidance cameras as well as an image mosaic with the panoramic camera.

Odometry:

As of sol 1402 (Dec. 13, 2007), Spirit's total odometry was 7523.31
meters (4.67 miles).

------------------------------------------------------------------------

OPPORTUNITY UPDATE: Opportunity Maneuvers Around Steeper Slopes in
"Victoria Crater" - sol 1375-1381, Dec 17, 2007:

Opportunity is now in the process of driving to the third band of
light-colored rocks that circumvent "Victoria Crater" beneath the rim.
Scientists had initially planned to have the rover head directly
downhill to a rock target nicknamed "Ronov," within the band known as
"Lyell." They selected an alternate rock exposure, dubbed "Newell," when
engineers determined that the original drive route would tilt the rover
25 degrees, somewhat higher than desired. The estimated tilt along the
new route is a much gentler 20 degrees but the drive is somewhat more
complex and required two days of planning.

During the past week, Opportunity completed scientific investigation of
the second band of rocks, known as "Smith," with an analysis of
elemental chemistry and iron-bearing minerals beneath the surface of a
rock exposure labeled "Smith2." To do this, the rover collected data
with the alpha-particle X-ray spectrometer Moessbauer spectrometer,
respectively.

If next week's planned drive goes as anticipated and closer inspection
of Newell deems it to be an acceptable target, Opportunity is likely to
stay at the new location for several weeks collecting data. Scientists
plan to have the rover conduct a complete campaign of studies with the
alpha-particle X-ray and Moessbauer spectrometers, microscopic imager,
rock abrasion tool, and on-board cameras.

During the planned drive, Opportunity will complete a "Get Quick Fine
Attitude," a procedure for determining the rover's position relative to
the changing position of the Sun. This activity recalibrates the
inertial measurement unit and eliminates tiny errors that accumulate
over time in pointing the antenna.

Opportunity is healthy and all subsystems are operating as expected. The
latest available power readings, taken on Martian day, or sol, 1379
(Dec. 10, 2007), show solar energy levels at a robust 601 watt-hours,
enough to light a 100-watt bulb for 6 hours.

Sol-by-sol summary:

In addition to morning uplinks directly from Earth via the rover's
high-gain antenna, evening downlinks to Earth via the Odyssey orbiter at
UHF frequencies, and standard measurements of atmospheric opacity caused
by dust using the panoramic camera, Opportunity completed the following
activities:

Sol 1375 (Dec. 6, 2007): Opportunity placed the alpha-particle X-ray
spectrometer on Smith2 and, after the overpass of the Odyssey orbiter,
collected data with the instrument. The next morning, when the Sun
powered the solar arrays, Opportunity scanned the sky for clouds with
the navigation camera.

Sol 1376: Opportunity conducted extensive measurements of atmospheric
dust and scanned the sky for clouds with the navigation camera.

Sol 1377: Opportunity placed the Moessbauer spectrometer on Smith 2 and
collected data with the instrument. Opportunity acquired calibration
images and part 1 of a panoramic view of the rover deck that involved 23
pointings with the panoramic camera. The rover surveyed the sky at high
sun with the panoramic camera and scanned the sky for clouds with the
navigation camera.

Sol 1378: Opportunity re-started the Moessbauer spectrometer and
continued data collection from Smith2. The rover acquired part 2 of a
panoramic view of the rover deck, completing 24 pointings of the
panoramic camera. Opportunity surveyed and took spot images of the sky
for calibration purposes using the panoramic camera.

Sol 1379: Opportunity re-started the Moessbauer spectrometer and resumed
data collection from Smith2. The rover then acquired part 3 of the
panoramic view of the spacecraft deck, a series that entailed 29
pointings of the panoramic camera. In the morning, Opportunity scanned
the sky for clouds with the navigation camera and monitored dust on the
rover mast assembly.

Sol 1380: Opportunity scanned the sky for clouds with the navigation
camera.

Sol 1381 (Dec. 12, 2007): Opportunity surveyed the sky at low sun with
the panoramic camera and measured argon gas in the Martian atmosphere
with the alpha-particle X-ray spectrometer. The rover searched for
clouds in the morning sky with the navigation camera.

Odometry:

As of sol 1379 (Dec. 5, 2007), Opportunity's total odometry remained at
11,584.32 meters (7.2 miles), where the rover has been stationed since
the last drive on Sol 1329 (Oct. 20, 2007).
Received on Mon 17 Dec 2007 07:36:37 PM PST