[meteorite-list] Curiosity Makes Its Longest One-Day Drive on Mars

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 23 Jul 2013 16:50:27 -0700 (PDT)
Message-ID: <201307232350.r6NNoRUK028820_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.php?release=2013-232

Curiosity Makes Its Longest One-Day Drive on Mars
Jet Propulsion Laboratory
July 23, 2013

PASADENA, Calif. - NASA's Mars rover Curiosity drove twice as far on
July 21 as on any other day of the mission so far: 109.7 yards (100.3
meters).

The length of the drive took advantage of starting the 340th Martian
day, or sol, of the mission from a location with an unusually good view
for rover engineers to plan a safe path. In weeks to come, the rover
team plans to begin using "autonav" capability for the rover to
autonomously navigate a path for itself, which could make such long
drives more frequent.

Curiosity is about three weeks into a multi-month trek, from the
"Glenelg" area where it worked for the first half of 2013, to an entry
point for the mission's major destination: the lower layers of Mount
Sharp. The mission's longest one-day drive prior to July 21 was about 54
yards (49 meters), on Sol 50 (Sept. 26, 2012). After completing the
longer drive, Curiosity drove 68.2 yards (62.4 meters) on July 23 (Sol
342), bringing the mission's total driving distance so far to 0.81 mile
(1.23 kilometers).

The Sol 340 drive included three segments, with turns at the end of the
first and second segments. Rover planners used information from stereo
imaging by the Navigation Camera (Navcam) on Curiosity's mast, plus
images from the telephoto-lens Mast Camera (Mastcam). The drive also
used the rover's capability to use imagery taken during the drive to
calculate the driving distance, a way to verify that wheels have not
been slipping too much while turning.

"What enabled us to drive so far on Sol 340 was starting at a high point
and also having Mastcam images giving us the size of rocks so we could
be sure they were not hazards," said rover planner Paolo Bellutta of
NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We could see for
quite a distance, but there was an area straight ahead that was not
clearly visible, so we had to find a path around that area."

The rover was facing southwest when the sol began. It turned slightly
more to the west before driving and used visual odometry to be sure it
drove the intended distance (about 55 yards or 50 meters) before turning
back farther southward. The second leg, next turn, and third leg
completed the drive without visual odometry, though the rover was using
another new capability: to turn on visual odometry autonomously if tilt
or other factors exceed predetermined limits.

New software on Curiosity gives it the capability to use visual odometry
through a range of temperatures. This was needed because testing this
spring indicated the Navcam pair linked to the rover's B-side computer
is more sensitive to temperature than anticipated. Without the
compensating software, the onboard analysis of stereo images could
indicate different distances to the same point, depending on the
temperature at which the images are taken. The rover was switched from
its A-side computer to the redundant B-side computer on Feb. 28 due to a
flash-memory problem -- subsequently resolved -- on the A-side. The
Navcam pair linked to the A-side computer shows less variability with
temperature than the pair now in use.

"For now, we're using visual odometry mostly for slip-checking," said
JPL's Jennifer Trosper, deputy project manager for Curiosity. "We are
validating the capability to begin using autonav at different
temperatures."

The autonomous navigation capability will enable rover planners to
command drives that go beyond the route that they can confirm as safe
from previous-sol images. They can tell the rover to use the autonomous
capability to choose a safe path for itself beyond that distance.

Curiosity landed at the "Bradbury Landing" location within Gale Crater
on Aug. 6, 2012, EDT and Universal Time (Aug. 5, PDT). From there, the
rover drove eastward to the Glenelg area, where it accomplished the
mission's major science objective of finding evidence for an ancient wet
environment that had conditions favorable for microbial life. The
rover's route is now southwestward. At Mount Sharp, in the middle of
Gale Crater, scientists anticipate finding evidence about how the
ancient Martian environment changed and evolved.

JPL, a division of the California Institute of Technology, Pasadena,
manages the Mars Science Laboratory Project for NASA's Science Mission
Directorate, Washington. JPL designed and built the project's Curiosity
rover.

More information about Curiosity is online at
http://www.jpl.nasa.gov/msl , http://www.nasa.gov/msl and
http://mars.jpl.nasa.gov/msl/ . You can follow the mission on Facebook
at http://www.facebook.com/marscuriosity and on Twitter at
http://www.twitter.com/marscuriosity .

Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster at jpl.nasa.gov

2013-232
Received on Tue 23 Jul 2013 07:50:27 PM PDT