17 years ago
OPPORTUNITY UPDATE: Back on the Plains - sol 313-319,
December 21, 2004
Opportunity examined tracks on its way to see its heat shield.
After six fruitful months exploring the interior of "Endurance Crater,"
the Opportunity rover has successfully climbed out of the crater onto
the surrounding flatland of Meridiani Planum. Once out, the rover
examined some of its own tracks that it had laid down prior to entering
the crater. It compared them side-by-side with fresh tracks in order to
observe any weathering effects in the intervening 200 sols. Opportunity
is now making its way toward an engineering examination of its heat
shield, which is located about 200 meters (220 yards) from the edge of
Endurance. Now that the vehicle is on the relatively flat plain rather
than tilted toward the Sun on the north-facing inner slope of the
crater, electrical output from its solar array has declined by about 15
percent. Opportunity remains in excellent health as it begins a new
phase of exploration.
Sol 312 and 313 were planned in a single planning cycle. Opportunity
still inside Endurance Crater. On sol 312 the plan began with backing
and using the panoramic camera and miniature thermal emission
spectrometer to observe a rock target called "Wharenhui," which had
treated with the rock abrasion tool on earlier sols. Subsequent
were to turn cross-slope, drive 7 meters (23 feet), turn upslope, and
drive an additional 6 meters (20 feet) uphill. Opportunity performed
drive perfectly, ending up approximately 5 meters (16.4 feet) from the
rim of Endurance Crater. Opportunity's tilt went from 25 degrees
pre-drive to 19 degrees post-drive.
Sol 313 was a restricted sol because results from the sol 312 drive
not available for planning sol 313. That meant that no driving or
robotic-arm activities were permitted. So Opportunity performed about
two hours of observations using the panoramic camera and miniature
thermal emission spectrometer and then went to sleep in the early
afternoon. The rover woke up to support late-afternoon and
communication relays by the orbiting Mars Odyssey.
Sols 314 through 316 were planned in another single planning cycle. The
plan was to complete the egress from Endurance Crater on sol 315, so
314 was another remote sensing sol. This would be the last full sol
inside Endurance. Opportunity spent about two and a half hours
with the panoramic camera and miniature thermal emission spectrometer.
It also performed a nighttime observation with the miniature thermal
emission spectrometer just before midnight. To ensure that Opportunity
had adequate power, the early-morning communication-relay session with
Odyssey was canceled and Opportunity went into a modified deep sleep
after completing the late-night observation.
Sol 315 was the big day for Opportunity. The rover was finally going to
leave Endurance Crater after spending 181 sols there! Opportunity was
instructed to drive 7 meters (23 feet) up and out of the crater. It was
a textbook drive. Everything went as planned and Opportunity had
finally, successfully completed a long and detailed series of
observations inside Endurance. Opportunity ended up on the plains of
Meridiani ready to begin the next chapter of its adventures.
Sol 316 was the third sol of a three-sol plan, and because Opportunity
had driven on sol 315, sol 316 was restricted to remote-sensing
observations. The rover performed about two hours of remote sensing and
went to sleep. Out on the plains, Opportunity went from a northerly
that is very good for solar exposure, to a southerly tilt that is not
good for solar exposure. The tilt was expected to be as high as 10
degrees, but Opportunity's actual tilt was about 5 degrees. Daily
from the solar panels went from 840 watt-hours in the crater, to 730
watt-hours on the plains.
Since the team continues to be operating in restricted sol mode, sols
317 and 318 were planned together as a two-sol plan. For sol 317, the
science team elected to drive toward wheel tracks that Opportunity had
made before entering Endurance Crater. The rover backed up about 5
meters (16.4 feet), performed some mid-drive imaging, and then
another 10 meters (33 feet) to put the old rover tracks into the work
volume of the robotic arm. Sol 318 was another remote-sensing sol,
during which Opportunity imaged its still-distant heat shield and
conducted a miniature thermal emission spectrometer observation of the
After the drive, both old and new tracks were directly in front of the
rover. On sol 319 Opportunity captured microscopic imager mosaics of
both types of tracks, then drove about 40 meters (131 feet) closer to
the heat shield, which will be examined carefully in future sols. Sol
319 ended on Dec. 17.