Mars Exploration Rover Update - September 20, 2007

http://marsrovers.jpl.nasa.gov/mission/status.html#opportunity

OPPORTUNITY UPDATE: ‘Shaking’ Off the Dust and Getting Back to Work - sol 1274-1281, Sep 20, 2007:

The skies continue to clear over the Opportunity site, and the dust is falling from both the sky and the rover. The last week was dedicated to evaluating the payload and assessing dust accumulation on the instruments. Fortunately, the solar array energy has improved to over 350 Watt-hours for the last four sols. This has given the vehicle enough power to support two alpha particle X-ray spectrometer integrations and two Mars Express UHF overflights.

The team began a campaign to recalibrate the panoramic camera tau observations used to measure the level of atmospheric opacity. The recalibration sequences are designed to run at various times of day to get the sun at different angles in the sky. Each sequence has custom exposure durations and color filters tailored to the intended time of execution.

As the team saw last week, the instruments on the robotic arm turret collected a substantial amount of dust during the storm. There are two main concerns: dust inside the alpha particle X-ray spectrometer and dust under the microscopic imager dust cover. On Spirit, dust managed to somehow find its way under the microscopic imager dust cover, so engineers are handling the dust-covered turret on Opportunity with care.

Twice in six sols, the team used the front hazard avoidance camera (and the panoramic and navigation cameras) to image the microscopic imager with the dust cover closed. There were two drives between each set of imaging and there is noticeable cleaning between the two. The first of several sky flats images taken with the microscopic imager (dust cover closed) came down today. Preliminary analysis indicates little to no dust on the lens or dust cover. Next week, the team will determine if it is safe to open the dust cover and take images to see if any dust is on the lens itself.

The first of two alpha particle X-ray spectrometer integrations was received on the ground today and the initial analysis shows little to no dust contamination. Argon peaks are just as large as before, but additional integrations are necessary to complete the analysis. In the meantime, the team modified the robotic arm ready position to face the alpha particle X-ray spectrometer in towards the vehicle’s warm electronics box. The hope is that this will prevent any dust from collecting inside.

Sol-by-sol summary:

Each sol contained: navigation camera tau at the start of the plan and a Mars Odyssey downlink in the afternoon.

Sol 1274: On this sol, the panoramic camera tau measurements were recalibrated. The team moved the robotic arm to place the microscopic imager in view of appropriate cameras for the following images: front hazard avoidance camera of the microscopic imager bore-sight, panoramic camera of MI bore-sight, panoramic camera of microscopic imager side view. Opportunity then finished work with the arm to move to modified ready position with the alpha particle X-ray spectrometer pointed towards the rover. More recalibrations of panoramic camera tau measurements were done before and after the Mars Odyssey pass. Finally, a panoramic camera image of rock target ‘Mango’ was shot.

Sol 1275: The vehicle remained in place due to a sequencing error that precluded the robotic arm from stowing before the planned drive. The uplink team corrected the logic error, and the rover resumed driving at the next opportunity on sol 1278. After the Odyssey pass, more tau recalibrations were conducted. The panoramic camera was also used to survey the horizon and image the sky.

Sol 1276: This sol was used to recharge. Some panoramic camera recalibrations were conducted.

Sol 1277: More panoramic camera tau measurement recalibrations began this sol. Afterwards, the robotic arm was moved into position to take a panoramic camera image of the microscopic imager from a side view. The panoramic camera took images of the sky. After the Odyssey pass, a tau measurement was taken and the alpha particle X-ray spectrometer was integrated for four hours. There was a Mars Express UHF pass and then Opportunity took a mini-deep sleep.

Sol 1278: The first part of this sol was used for more panoramic camera tau recalibrations and panoramic camera mast assembly (“head” and “neck”) dust monitoring. The panoramic camera was also used to image the sky. Another recalibration took place before the rover stowed its arm and drove 1.43 meters (4.7 feet) using visodom (visual odometry software) on its closest approach toward the crater rim. Opportunity then conducted post-drive navigation camera images. After the Odyssey pass, more panoramic camera recalibrations were conducted.

Sol 1279: On this sol, the microscopic imager, navigation camera and panoramic cameras were all used to image the sky. More recalibrations were conducted before and after the Odyssey pass. The alpha particle X-ray spectrometer was integrated for 5.5 hours.

Sol 1280: A panoramic camera tau recalibration was conducted in addition to a panoramic camera tau measurement. The navigation camera took an image. The panoramic camera used its 13 filters to image a bright ripple. Before and after the Odyssey pass, more recalibrations took place.

Sol 1281: The first part of this sol was used to conduct a panoramic camera tau recalibration, to monitor dust on the panoramic camera mast assembly and to image the sky with the panoramic camera. The panoramic camera then imaged “Duck Bay.” Before and after the Odyssey pass, more recalibrations were conducted.

Odometry:

As of sol 1279, Opportunity’s total odometry is 11,483.39 meters (7.14 miles).