[meteorite-list] Mars Exploration Rover Update - November 8, 2004

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue Nov 9 12:16:18 2004
Message-ID: <200411091716.JAA07134_at_zagami.jpl.nasa.gov>

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

OPPORTUNITY UPDATE: Journey toward 'Burns Cliff' Continues -
sol 265-271, November 08, 2004

Opportunity's trek towards "Burns Cliff" continues. The journey has been
much more difficult than anticipated. The rover has experienced drive
slippage of up to 100 percent. The plan is to attempt a couple of sols
of up-slope, switchback driving and then review options to get to Burns
Cliff.

The rover team celebrated Opportunity's 300-percent mission success
anniversary on sol 270. The rover is showing no signs of slowing down
despite its advanced age. Spacecraft health is excellent, and solar
power is plentiful.

Sol details:

On sol 265 Opportunity began its drive away from a boulder called
'Wopmay.' The rover performed 45 minutes of remote observations and then
attempted a 21-meter (69-foot) drive away from Wopmay. The drive stopped
after 3.5 meters (11.5 feet). Opportunity experienced a drive and
mobility goal error due to high current draw in the steering motors.

Sols 266, 267, and 268 were planned as a single 3-sol weekend plan. Due
to the rover's heading at the end of sol 265, the morning uplink session
on sol 266 was occluded by the panoramic camera, raising concern that we
might fail to get the 3-sol command load to the spacecraft. To avoid
this problem, the team instead chose to implement a high-priority
communication window at 11:30 local solar time and to uplink all
sequences at that time, activating the sol 266 master sequence by
real-time command. This plan worked as designed, and all sequences got
onboard.

The original plan for sols 266 and 267 was to place the alpha particle
X-ray spectrometer on the filter magnet for extended integrations.
However, Opportunity's position against a buried rock (informally named
"Son of Bane") and the churning up of sandy terrain meant that we could
not rule out the possibility of an unseen rock in the robotic arm's work
volume. As a consequence, the arm deployment was cancelled, and the
activities for sols 266-267 were limited to remote-sensing observations.

On sol 268, Opportunity drove away from Son of Bane. The rover turned
and drove forward a short distance to get out of the hole it had dug for
itself. It drove about 4.5 meters (about 15 feet) cross slope, and then
began an up-slope drive designed to cover 9 meters (29.5 feet). Only
about 0.4 meter (1.3 feet) of this last leg was achieved before the
rover again encountered 100 percent slip.

Due to the large slippage and unsuccessful drive on sol 269, the day was
used to take detailed images of the rover's position and to allow the
rover mobility team to plan drive strategies for subsequent sols.
Opportunity performed more than two hours of remote observations. The
rover began a routine of forfeiting deep sleep for as many sols as the
battery state of charge would allow. Solar exposure has been favorable
enough to reduce the need for deep sleep. In an effort to reduce the
backlog of onboard science telemetry that has not been downlinked,
Opportunity will support early morning Mars Odyssey communication
sessions as long as the battery state of charge is not impaired.

Sol 270 was the first sol dedicated to a potpourri of mobility maneuvers
to gain a better understanding of the terrain on which Opportunity is
driving. The rover completed the drive with no errors and achieved a
positive elevation change of more than a meter (3.3 feet). Driving at a
45-degree angle to the slope appears to be the most productive operation.

With enthusiasm running high, the uplink team employed strategies of the
drive from sol 270 to plan sols 271's drive. Opportunity was to drive
up-slope at an angle heading east, towards Burns Cliff, as part of a
longer switchback drive operation. But as has often been the case
recently, the drive was not successful. Opportunity moved 0.78 meters in
a beeline (about 2.6 feet) but experienced 100 percent slippage for most
of the drive and ended up approximately 0.35 meters (1.1 feet) lower.
Sol 271 ended on Oct. 28, PDT.

The result of this drive calls into question Opportunity's ability to
reach Burns Cliff with the current approach. The team is assessing other
possibilities.

Total odometry after sol 271 is 1664.43 meters (1.03 miles).
Received on Tue 09 Nov 2004 12:16:15 PM PST