[meteorite-list] Mars Exploration Rover Update - July 9, 2004
From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri Jul 9 20:22:15 2004
SPIRIT UPDATE: Spirit Tries Out Visual Odometry - sol 175-178,
July 09, 2004
On sol 175, Spirit analyzed the new targets "Breadbox" and "Sourdough"
with its panoramic camera and miniature thermal emission spectrometer.
Spirit then got an up-close look at Breadbox with the microscopic
imager, and deployed the M?ssbauer spectrometer on Sourdough for an
overnight integration. In the middle of the martian night, Spirit did a
tool change to the alpha particle X-ray spectrometer and completed a
five-hour integration before the sol 176 plan began.
Spirit spent sol 176 getting a battery re-charge and a front hazard
avoidance camera calibration. The evening of sol 176, engineers
commanded Spirit to wake up and enable the panoramic camera mast
actuator heater so they could determine when the thermostat turns the
heater on. The heater turned on when expected, which will allow Spirit
to conduct a night-time miniature thermal emission spectrometer
observation in a few sols.
On sol 177, Spirit successfully performed a series of observations on an
interesting and shiny feature called "String of Pearls." The rover
acquired two microscopic images of the target and an overnight
integration with the M?ssbauer spectrometer and alpha particle X-ray
spectrometer. As Mars' southern winter approaches, Spirit's energy
resources become increasingly limited. Overnight tool changes and their
associated heating take a big toll on the limited energy budget, and
require some preparation and recovery to keep up Spirit's battery charge.
Spirit began sol 178 by stowing the robotic arm and then backing up 1.5
meters (about 5 feet) from "Hank's Hollow" in order to properly place
the miniature thermal emission spectrometer to get a good view of "Pot
of Gold" and nearby rover tracks. Engineers also took this opportunity
to use visual odometry for the first time on Spirit. This is a technique
in which the rover takes successive images of its surroundings during a
drive and then matches features in those images on-board to compute how
far and in what direction it has moved. Both the drive and the test went
well, and ground verification showed that the matching worked quite
nicely with the features in this terrain. Visual odometry will be
important if and when Spirit starts driving on five wheels, since the
actual drives can and will be rather different than what is commanded.
The rover can use the visual odometry estimates while driving to
compensate for the slipping and yawing that engineers expect with
Received on Fri 09 Jul 2004 08:22:12 PM PDT