[meteorite-list] Mars Exploration Rover Update - November 13, 2007

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 14 Nov 2007 17:06:44 -0800 (PST)
Message-ID: <200711150106.RAA12615_at_zagami.jpl.nasa.gov>

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

OPPORTUNITY UPDATE: Rover Finds Way to Brush Rock Surfaces Despite
Setbacks - sol 1343-1348, Nov 13, 2007:

Opportunity is still parked in front of the rock layer known as "Smith"
inside Victoria Crater. The rover has now lost two encoders that operate
motors on the rock abrasion tool during the grinding and brushing of
surfaces. Science team members and engineers have been working in test
beds and computer sequencing rooms to devise creative ways of using the
rock abrasion tool without the grind and revolve encoders.

On sol 1347 (Oct. 7, 2007), they achieved their goal when Opportunity
successfully completed a new, seek-scan procedure. Using this technique,
the rover locates a rock surface by simultaneously spinning its grind
teeth and wire brush while also extending toward the rock surface.
Normally, the rock abrasion tool software monitors the safe operation of
the grind or brush using the two encoders, which detect stalls that can
occur during grinding and encoding. In the event of a stall, the
encoders measure the z-axis position (the point where the rock abrasion
tool contacts the rock surface). Without the encoders, engineers must
rely on current limits and contact switches to know when grind teeth
come into contact with a rock surface.

Opportunity followed a command to run both the grind and revolve motors
along with a parallel command to move in toward the rock surface. When
the rock abrasion tool made contact with the surface, contact switches
disengaged, ending the activity. The following day, sol 1348 (Oct. 8,
2007), the science team directed the rover to retract the rock abrasion
tool 1 millimeter and brush the surface. The brushing proceeded as planned!

Grind testing will continue next week using a rock abrasion tool with
new grind bits on a surrogate rover on Earth in preparation for grinding
new targets on Smith.

Opportunity is also scheduled to test communications next week with
NASA's Mars Reconnaissance Orbiter. This test, along with other tests
conducted recently with the European Space Agency's Mars Express
orbiter, are demonstrations of the capability to conduct UHF
communications in preparation for next year's arrival of the Phoenix
lander.

Opportunity's solar array energy has been approximately 670 watt-hours
(100 watt-hours is the amount of energy needed to light a 100-watt bulb
for one hour) per sol with atmospheric dust opacity, known as tau, of 0.87.

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, standard measurements of atmospheric dust with the
panoramic and navigation cameras, and surveys of the horizon with the
panoramic camera, Opportunity completed the following activities:

Sol 1343 (Nov. 3, 2007): Opportunity ran diagnostic tests of the rock
abrasion tool and collected compositional data from Smith using the
Moessbauer spectrometer. The rover relayed data overnight to Odyssey.

Sol 1344: Opportunity continued to acquire compositional data from Smith
with the Moessbauer spectrometer and scanned the sky for clouds with the
navigation camera. Opportunity took full-color images, using all 13
filters of the panoramic camera, of a rock target known as "Jin," and
took panoramic camera images of Smith and the rock layer known as "Lyell."

Sol 1345: Opportunity continued the compositional analysis of Smith with
the Moessbauer spectrometer and monitored dust on the camera mast. The
rover acquired color images using all 13 filters of the panoramic camera
of a rock target dubbed "Gressly," scanned the sky for clouds, and took
thumbnail images of the sky with the panoramic camera.

Sol 1346: Opportunity ran more diagnostic tests of the rock abrasion
tool, placed the Moessbauer spectrometer back on Smith, and collected 11
hours' worth of compositional data with the instrument. The rover
acquired a mosaic of images of Lyell as well as spot images of the sky
with the panoramic camera.

Sol 1347: Opportunity completed a seek-scan procedure with the rock
abrasion tool (during which the rover locates a rock surface by
simultaneously spinning its grind teeth and wire brush while extending
toward the rock surface). In addition, Opportunity took panoramic camera
images of Lyell, measured atmospheric argon with the alpha-particle
X-ray spectrometer, relayed data to the Odyssey orbiter overnight, and
scanned the sky for clouds with the navigation camera.

Sol 1348 (Nov. 8, 2007): Plans called for Opportunity to complete an
encoder-less brush of the surface of Smith, acquire microscopic images
of Smith, place the alpha-particle X-ray spectrometer on Smith, and
study composition of Smith with the spectrometer. The rover was to take
panoramic camera images of "Cabo Frio," a promontory at the rim of
Victoria Crater. Opportunity was to acquire full-color images, using all
13 filters of the panoramic camera, of a layered rock target known as
"Brongniart."

Odometry:

As of sol 1348 (Nov. 8, 2007), Opportunity's total odometry remained at
11,584.32 meters (7.2 miles).
Received on Wed 14 Nov 2007 08:06:44 PM PST