Mars Exploration Rover Update - July 15, 2005

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

OPPORTUNITY UPDATE: Edging Toward 'Erebus' - sol 518-524, July 15,
2005:

Opportunity made impressive progress toward "Erebus Crater" during the
week. Four sols of driving totaled 57 meters (187 feet), while slipping
less than 10 percent on each drive. A longer drive was plotted for the
fifth day.

The rover has continued to drive down ripple troughs. We have a series
of checks in place to prevent excessive bogging down, including, tilt,
roll, pitch limit checks, current checks and slip checks (set at 40
percent slip).

We look forward to more progress south over the coming week.

Sol-by-sol summaries:

Sol 518 and 519 (July 9 and July 10, 2005): In light of extensive
driving and data collection the previous week, these sols were designed
to conduct light remote sensing, recharge batteries, and downlink data
to free up memory space on the rover.

Sol 520: The uplink team designed a 16-meter (52-foot) drive.
Opportunity completed 10.34 meters (33.92 feet) of the drive before
tripping a mobility-goal error. There was a bad position estimate given
to the onboard slip-checking software, so it incorrectly thought the
rover was 0.5 to 1 meters (1.6 to 3.3 feet) back from its actual
position, thus making insufficient progress because it thought it was
slipping excessively. However, analysis by the mobility team on the
ground determined the true slip, and we were "go" to drive the
following
sol.

Sol 521: Opportunity completed a successful drive of 15.2 meters (about
50 feet) without any faults.

Sol 522: The rover completed another successful drive of 15 meters (49
feet), with only 6.4 percent reported slip.

Sol 523: We drove 16.2 meters (53 feet) of a planned 20-meter (66-foot)
drive. The drive stopped short because onboard slip-checking software
was having difficulty tracking the rover's rear wheel tracks, which are
used as a reference point to monitor the slip. Opportunity does not
want
to keep trying to drive if it is unsure of how much it is slipping, so
the team sets a limit to this failure count. This prevents bogging down
in the terrain.

Sol 524 (July 15): The uplink team planned a drive of 27 meters (89
feet). The drive plan is the first in Opportunity's current terrain
using a combination of short segments of blind driving followed by
shorter segments (40 centimeters, or 16 inches) of slip-check driving.
This drive strategy is designed to allow us to drive farther by using a
less time-consuming drive option while still verifying every 5 meters
that we are not bogging down.

Odometry total after sol 523 drive: 5464.09 meters (3.39 miles).