From Newsgroup: sci.space.news


OPPORTUNITY UPDATE: Climbing to Clay-Mineral Site Seen from Orbit -
sols 4324-4330, March 23, 2016-March 29, 2016:

Opportunity is exploring the south side of 'Marathon Valley' located on
the rim of Endeavour crater. The rover is up on the slopes of 'Knudsen
Ridge.'

The objective is to identify specific outcrops for evidence of clay minerals. Opportunity has been driving towards high-slope regions that show evidence
for clay minerals observed from orbit. With each drive the rover has bee collected extensive pre-drive and post-drive Panoramic Camera (Pancam)
and Navigation Camera (Navcam) panoramas to document the terrain.

On Sol 4325 (March 24, 2016), Opportunity drove west intending to cover
about 49 feet (15 meters), but only achieved about 22 feet (6.8 meters). Visual Odometry (VO), which is used to track the rover's progress and direction, had difficulty converging on the featureless terrain around
the rover. Visual Odometry works by tracking local surface features in
the terrain as the rover moves. Another drive was sequenced on Sol 4328
(March 27, 2016), for about 79 feet (24 meters), but again the drive stopped after only 55 feet (16.9 meters) again due to lack of VO convergence on
the featureless terrain. More progress was made on the next sol with a
22-foot (6.6-meter) drive to the southwest and on Sol 4330 (March 29,
2016), with a 43-foot (12.9-meter) drive also to the southwest.

Opportunity is now believed to be in the area of the clay minerals seen
from orbit. The rover is documenting the terrain with extensive Pancam
color (multi-filter) panoramas. Energy levels have also improved markedly,
a combination of improving solar insolation with season and dust cleaning events on the solar arrays.

As of Sol 4330 (March 29, 2016), the solar array energy production has increased to 650 watt-hours with an atmospheric opacity (Tau) of 0.589
and an improved solar array dust factor of 0.857 (although this number
may be affected by atmospheric clouds).

Total odometry is 26.55 miles (42.74 kilometers), more than a marathon.

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