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Spirit Tries to Coax Dust from Microscopic Imager
Aug. 24, 2007
sol 1288-1294
For the first time since arriving on Mars in 2004, Spirit attempted to remove dust from the microscopic imager in a "blobs away" campaign to help the rover recover from a series of dust storms. The rover remained healthy as the Gusev Crater region continued to emerge from the recent storms. Gloominess caused by suspended dust in the atmosphere remained high but continued its downward trend. Dust falling out of the atmosphere continued to accumulate on the solar panels, limiting power gains from decreasing atmospheric opacity, known as Tau.
Between the rover's 1,288th and 1,291st Martian days, or sols, of exploration (Aug. 18 and Aug. 21, 2007), Tau values went down from 3.2 to 3.0. During the same time, the accumulation of dust on the solar arrays rose from 0.664 to 0.640 (a dust factor of 1.0 corresponds to a perfectly clean array). Solar energy on sol 1291 (Aug. 21, 2007) was 313 watt-hours (100 watt-hours is what it takes to light a 100-watt bulb for 1 hour).
The "blobs away" campaign, designed to dump dust from the surface of the microscopic imager lens, involved repeatedly taking images, opening and closing the dust cover, pointing the instrument slightly upward at an angle of 20 degrees (with the hinge down to avoid dumping caked dust on the lens), and taking more images and opening and closing the dust cover. Improved image quality after the procedure indicated that either some dust fell out or simply moved around. Dust decontamination efforts continue.
Spirit acquired microscopic images of mobile surface ripples and a soil target nicknamed "Norma Luker" on Sol 1291 (Aug. 21 2007). Despite dust motes on the lens, the images were useful to the science team.
Engineers were investigating the cause of a failed transmission on sol 1292 (Aug. 22, 2007), in which planned activities did not get on board the spacecraft. Potential causes being investigated included an uplink glitch or interference from a simultaneous uplink to the Mars Reconnaissance Orbiter.
Spirit "drove" 42 centimeters (16 ˝ inches) to a new position. Weekend plans called for the first multi-meter drive toward the elevated plateau known as "Home Plate" as well as test transmissions to the European Mars Express orbiter in support of next year's arrival of the Phoenix spacecraft now en route to Mars.
Martian weather reports as of Aug. 22 indicated a lull in afternoon storm activity on the red planet, with no new storm activity visible within a few thousand kilometers of either Mars rover site. Skies remained dusty and were expected to continue to clear slowly.
Sol-by-sol summary:
In addition to daily direct-from-Earth uplinks over the rover's high-gain antenna, relays to Earth at UHF frequences via the Odyssey orbiter, surveys of the sky and ground with the miniature thermal emission spectrometer, measurements of atmospheric opacity with the panoramic and navigation cameras, and image acquisition with the front and rear hazard avoidance cameras, Spirit completed the following activities:
Sol 1288 (Aug. 18, 2007): Spirit studied Norma Luker with the alpha-particle X-ray spectrometer.
Sol 1289: Spirit monitored dust accumulation on the rover mast, collected data on the external calibration target with the miniature thermal emission spectrometer, and completed a survey at high sun with the panoramic camera.
Sol 1290: Spirit surveyed the horizon with the panoramic camera and performed dust ejection maneuvers with the microscopic imager.
Sol 1291: Spirit took thumbnail images of the sky with the panoramic camera, checked for drift (changes with time) in the miniature thermal emission spectrometer, and acquired stereo microscopic images of Norma Luker. The rover moved the microscopic imager and acquired stereo microscopic views of surface ripples, stowed the robotic arm, and acquired hazard avoidance camera images to document the stowing of the arm.
Sol 1292: Plans for a day of remote sensing and acquisition of full-color images of a target known as "Eileen Dean" failed to get on board.
Sol 1293: Spirit checked for drift in the miniature thermal emission spectrometer, acquired movie frames in search of dust devils using the navigation camera, and took full-color images using all 13 filters of the panoramic camera of a target known as "Gertrude Weise12." The rover acquired miniature thermal emission spectrometer data from the same target before rolling a short distance away. After the short drive, the rover took images of its new location with the navigation camera and hazard avoidance cameras.
Sol 1294 (Aug. 24, 2007): Plans called for Spirit to check for drift in the miniature thermal emission spectrometer, acquire movie frames in search of dust devils with the navigation camera, and survey the horizon with the panoramic camera.
Odometry:
As of sol 1293 (Aug. 23, 2007), Spirit's total odometry was 7,154 meters (4.45 miles).
Source: NASA
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