Mars Exploration Rover Update - July 16, 2007

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

SPIRIT UPDATE: Spirit Examines Rocks Possibly Formed In Volcanic Gases
or Hot Springs - sol 1247-1252, July 16, 2007:

Spirit is healthy after driving to a cluster of rock fragments known
as
"Innocent Bystander" (so named because Spirit accidentally ran over it
when another rock, "Virginia Bell," was the intended target. The aim
had
been to crush Virginia Bell to expose a fresh surface for
examination).

It was a fortuitous encounter, though, because indications are that
Innocent Bystander may have been formed by either a fumarole or hot
spring. A fumarole is a vent in the Earth's surface that emits steam
and
volcanic gases. Volcanic gases leach the original rock and leave
silica-rich rock behind. If Innocent Bystander was created in a hot
spring environment, then it could be siliceous sinter, a kind of
silica-rich rock that precipitates directly from water.

Spirit had a solar-array dust-cleaning event on the rover's 1,252nd
day,
or sol, of Martian exploration (July 12, 2007). Even though Tau, a
measurement of atmospheric opacity caused by dust, has been trending
upward for the past several days, Spirit's solar power levels have
risen
slightly due to wind-related cleaning of the solar panels.

Sol-by-sol summary:

In addition to daily remote science observations of the atmosphere and
terrain using the panoramic camera and the miniature thermal emission
spectrometer, and communication activities including morning
direct-from-Earth uplinks via the rover's high-gain antenna and
evening
downlinks at UHF frequencies via the Mars Odyssey orbiter, Spirit
completed the following activities:

Sol 1247 (July 6, 2007): Spirit monitored atmospheric dust with the
panoramic camera, scanned the sky and ground with the miniature
thermal
emission spectrometer, stowed the robotic arm, and drove to Innocent
Bystander. Along the way, Spirit acquired mid-drive, full-color images
of the work volume using all 13 filters of the panoramic camera as
well
as images with the hazard avoidance cameras. After transmitting data
to
the Odyssey orbiter, Spirit again measured atmospheric dust and took
images of the sun with the navigation camera.

Sol 1248: In the morning, Spirit monitored atmospheric dust and
surveyed
the horizon with the panoramic camera, monitored dust on the rover
mast,
and acquired thumbnail images of the sky. Spirit then continued to
measure atmospheric dust and scan the sky and ground with the
miniature
thermal emission spectrometer. The rover completed a calibration of
the
miniature thermal emission spectrometer as well as a survey of the sky
and ground with the instrument. Spirit completed a survey at high Sun
with the panoramic camera. After communicating with the Odyssey
spacecraft, Spirit measured atmospheric dust.

Sol 1249: In the morning, Spirit monitored atmospheric dust with the
panoramic camera, watched for dust devils, and acquired movie frames
of
potential dust devils with the navigation camera. Spirit continued to
measure atmospheric dust opacity with the panoramic camera and scan
the
sky and ground witht the miniature thermal emission spectrometer.
After
the uplink to the Odyssey orbiter, Spirit continued to measure
atmospheric opacity with the panoramic camera.

Sol 1250: In the morning, Spirit measured atmospheric opacity with the
panoramic camera and surveyed the sky and ground with the miniature
thermal emission spectrometer. Spirit checked for drift (changes with
time) in the miniature thermal emission spectrometer. Spirit drove
closer to Innocent Bystander and acquired post-drive images with the
hazard avoidance cameras and a 360-degree panorama with the navigation
camera. The rover continued to measure atmospheric opacity with the
panoramic camera and scan the sky and ground with the miniature
thermal
emission spectrometer. After communicating with Odyssey, Spirit
acquired
navigation camera images of the Sun and again monitored atmospheric
dust
with the panoramic camera.

Sol 1238: In the morning, Spirit monitored dust build-up on the
rover's
mast, surveyed the horizon with the panoramic camera, and acquired
movie
frames with the navigation camera in search of dust devils. Spirit
acquired microscopic images of the solar arrays, capture magnet, and
filter magnet to document dust levels since the most recent
dust-cleaning events on sols 1233 and 1234 (June 22-23, 2007). The
rover
acquired microscopic images of Eileen Dean and collected data on the
target using the alpha-particle X-ray spectrometer. Spirit acquired
four
sets of comparative measurements with the miniature thermal emission
spectrometer early in the day, in the afternoon, overnight, and early
the next sol. Spirit observed the Sun with the navigation camera in
support of the Mars Science Laboratory rover scheduled for launch in
2009. The goal of these observations is to see if navigation camera
images of the sun can be used to orient the rover.

Sol 1251: Upon awakening, Spirit acquired images of the Sun using the
navigation camera, measured atmospheric opacity with the panoramic
camera, completed a survey of clasts using the panoramic camera, and
surveyed the sky and ground with the miniature thermal emission
spectrometer. Spirit continued to monitor atmospheric dust and scan
the
surroundings, then unstowed the robotic arm and acquired a 2x1x7
mosaic
of microscopic images of Innocent Bystander. Spirit placed the
alpha-particle X-ray spectrometer on Innocent Bystander, measured
atmospheric dust and completed a survey at high Sun with the panoramic
camera, and continued to monitor atmospheric dust and survey the
surroundings. Spirit acquired thumbnail images of the sky using the
panoramic camera, measured late atmospheric dust opacity, and scanned
the calibration target and surveyed the sky and ground with the
miniature thermal emission spectrometer. Spirit took a nap and awoke
at
11:10 p.m. local Mars time to begin an alpha-particle X-ray study that
was to last just under 12 hours.

Sol 1252 (July 12, 2007): After solar array wakeup, Spirit was slated
to
continue measuring atmospheric opacity with the panoramic camera,
acquire images of the Sun with the navigation camera, and survey the
sky
and ground with the miniature thermal emission spectrometer.

Odometry:

As of sol 1250 (July 10, 2007), Spirit's total odometry remained at
7,153 meters (4.44 miles).