OPPORTUNITY UPDATE: Opportunity Grinds into Rock in “Victoria Crater” - sol 1368-1374, Dec 10, 2007:
Opportunity spent part of the past week carefully grinding a hole into the surface of a light-colored ring of rock inside “Victoria Crater” known as “Smith,” despite the previous loss of encoders that enabled two of the motors of the rock abrasion tool to operate under control of the tool’s flight software. The endeavor was successful, with the rover grinding to a depth of about 1 millimeter - about the thickness of a dime - deep enough to allow measurement of the rock chemistry beneath the surface. The rover is healthy and all systems are normal.
Rover engineers devised and tested a novel approach for operating the rock abrasion tool that enabled it to locate the surface independent of the encoders on the grind and revolve motors. Opportunity implemented a “Grind Scan” procedure to find the surface on sol 1368 (Nov. 29, 2007). Two days later, on sol 1370 (Dec. 1, 2007), Opportunity ground into the surface. Though the science team originally planned to have the tool grind 2 millimeters into the surface, the contact switches that engaged when the tool was placed on the rock released, likely due to vibration under a light pre-load of the RAT against the target. This release caused the grinding to halt at half the planned depth. Images sent to Earth showed that even though the hole was somewhat unusual in appearance as the result of a bent wire brush, it was suitable for analysis using the alpha-particle X-ray spectrometer.
Images of the sky taken on sol 1373 (Dec. 4, 2007) showed that some of the dust had cleared from the lens of Opportunity’s microscopic imager.
Working with NASA’s Mars Reconnaissance Orbiter, Opportunity completed the second of two communications tests verifying the relay capability of the orbiter in preparation for the Phoenix mission, now en route to Mars. The second round of testing involved the use of the Electra telecommunications package on the orbiter to measure the distance and speed of incoming spacecraft relative to Mars based on UHF radio signals and to measure the location of a landed spacecraft on the surface of Mars. Opportunity provided useful data for both measurements - using the “relative window” mode and the “fixed window” mode.
Opportunity continued to generate abundant solar power levels of 638 watt-hours, enough energy to light a 100-watt bulb for more than 6 hours, measured on Martian day, or sol, 1373 (Dec. 4, 2007). Scientists planned to have the rover finish up work on Smith and then descend to the last of three light-colored rings of rock. This final ring is known as “Lyell.”
In addition to morning uplinks directly from Earth via the rover’s high-gain antenna, evening downlinks to Earth via the Odyssey orbiter at UHF frequencies, and standard measurements of atmospheric opacity caused by dust using the panoramic and navigation cameras, Opportunity completed the following activities:
Sol 1368 (Nov. 29, 2007): Opportunity completed the “Grind Scan” procedure to find the rock surface to be ground, tested UHF communications with the Mars Reconnaissance Orbiter, and acquired panoramic camera images, including part 5 of a panorama of a light- toned exposure of rock known as “Pettijohn.” Upon awakening the next morning, Opportunity scanned the sky for clouds using the navigation camera.
Sol 1369: Opportunity took extensive measurements of atmospheric dust and searched for clouds using the navigation camera.
Sol 1370: Opportunity ground into the surface of the rock target known as “Smith2,” acquired images of the sky with the microscopic imager to monitor dust on the instrument lens, and measured argon gas in the Martian atmosphere with the alpha-particle X-ray spectrometer. The next morning, the rover scanned the sky for clouds using the navigation camera.
Sol 1371: Opportunity acquired full-color images, using all 13 filters of the panoramic camera, of Smith2. The rover acquired additional images with the panoramic camera, including part 6 of the Pettijohn panorama.
Sol 1372: Opportunity surveyed the sky at high sun with the panoramic camera, took extensive measurements of atmospheric dust, scanned the sky for clouds with the navigation camera, and took spot images of the sky to calibrate the panoramic camera.
Sol 1373: Opportunity acquired stereo, microscopic images of Smith2, surveyed the rock abrasion tool and the grinding bit with the panoramic camera, and took more full-color images, using all 13 filters of the panoramic camera, of Smith2. Opportunity took images of the sky with the microscopic imager to characterize dust on the lens and scanned the sky for clouds with the navigation camera.
Sol 1374 (Dec. 5, 2007): In addition to measuring atmospheric dust, Opportunity scanned the sky for clouds using the navigation camera, surveyed the sky with the panoramic camera, and took thumbnail images of the sky with the panoramic camera.
As of sol 1374 (Dec. 5, 2007), Opportunity’s total odometry remained at 11,584.32 meters (7.2 miles), where the rover has been stationed since the last drive on Sol 1329 (Oct. 20, 2007)