Mars Rovers Update
15 Jul 2004
(Source: Jet Propulsion Laboratory)
SPIRIT UPDATE: Spirit Reaches 180 Sols! - sol 179-180, July 15, 2004
On sol 179, Spirit woke up at a new location and spent the day performing remote sensing with the miniature thermal emission spectrometer, including an overnight observation.
Sol 180 marked a grand accomplishment for Spirit. The rover has survived two times the original planned mission duration of 90 sols. On this notable sol, the rover continued with remote sensing, performing miniature thermal emission spectrometer observations on disturbed soil and rover tracks. Spirit then looked at the targets "Cookie Cutter" and "Julienned" with the panoramic camera. Because of power and timing issues, Spirit was not able to complete intended microscopic imaging, M?ssbauer spectrometer, and alpha particle X-ray spectrometer measurements at this site. These operations were moved into the sol 181 plan. Total odometry after sol 180 is 3414 meters (2.1 miles).
OPPORTUNITY UPDATE: Opportunity Reading Rock Within its Reach - sol 159-163, July 15, 2004
Opportunity has not moved (intentionally or otherwise) since its stabilizing maneuver on sol 158. The rover has been using the instruments on its arm and mast to study the rocks at its current location, which is in the sixth layer encountered on the way into "Endurance Crater." Opportunity remains in excellent health. Deep sleep has been invoked every other night to save energy; the miniature thermal emission spectrometer continues to operate nominally despite temperatures as low as -53 degrees Celsius (-127 degrees Fahrenheit) on some nights.
Opportunity is due for a set of "corrective lenses" (new hazard-avoidance camera models) after the trial run of new camera models is complete on Opportunity's twin rover, Spirit. In the meantime, the rover team has been using microscopic imager mosaics to locate targets when the hazard-avoidance camera-based targeting is not sufficient.
The mechanical team is investigating an anomaly involving the door on the alpha particle X-ray spectrometer. The spectrometer has two contact switches; one that indicates its doors are open, another that indicates it is fully in contact with its target. For the purpose of opening the alpha particle X-ray spectrometer doors on sol 161, engineers placed the spectrometer on the compositional calibration target, a rock disc with a known composition that is located on the underbelly of Opportunity. It is used to calibrate the M?ssbauer instrument periodically. The team expected both contact switches to trip on that move; only the in-contact switch tripped. The next sol, when the spectrometer was removed from its rock target, a front hazard-avoidance camera image indicated that the doors were fully open. A subsequent move to close the doors resulted in only partial closure. The team tried again to open, then close the doors and was successful, with the doors fully open, then fully closed during that maneuver. The door-open contact switch, however, once again did not trigger as expected during that maneuver. Since the team is still able to safely open and close the alpha particle X-ray spectrometer doors, full use of the instrument is not compromised.
sol 159: The operations team planned this sol's activity a day in advance so that they could a enjoy a much-deserved holiday on July 4th, resulting in a relatively quiet sol on Mars for Spirit. The sol's activities included daily miniature thermal emission spectrometer and panoramic camera atmospheric observations. A calibration of the miniature thermal emission spectrometer vertical scan mirror actuator was also conducted. The vertical scan mirror actuator operates like a periscope, allowing the miniature thermal emission spectrometer to target things vertically from the ground to the sky.
sol 160: Opportunity forfeited deep sleep overnight from sol 159 to sol 160 to take advantage of an optimal communication window with Mars Odyssey. We used the microscopic imager to take a mosaic of the "Drammensfjorden" location on the rock "Millstone," which is in layer "F" of Endurance Crater. The microscopic images were taken to enable the accurate placement of the rock abrasion tool on sol 161. The M?ssbauer spectrometer was then placed on the compositional calibration target (CCT). This was the first such use of the CCT and was done partially out of concern that the instrument's behavior might be affected by the rover's present tilt of roughly 25 degrees. The rover team put Opportunity into a deep sleep the night of sol 160.
sol 161: The rover awoke from deep sleep to make some early morning atmospheric observations, including another attempt to image clouds. Later that morning the M?ssbauer instrument was stopped and removed from the CCT. The rock abrasion tool was then used on the target Drammensfjorden, creating a 6.3mm (a quarter of an inch)-deep hole during the two and one-half hour sequence. The day ended with more atmospheric observations and a placement of the alpha particle X-ray spectrometer on the abraded rock abrasion tool hole.
sol 162: Opportunity woke up in the wee hours of sol 162 for an Odyssey communication session and to start the alpha particle X-ray spectrometer observation. The alpha particle X-ray spectrometer collected data from the hole in Drammensfjorden until 10:30 a.m. local solar time. The data indicated that the alpha particle X-ray spectrometer doors were fully open, despite the failure of the door-open switch to trigger when the doors were opened on the CCT. The rover then took a series of microscopic images of the rock abrasion tool hole before starting a M?ssbauer integration at the same location. The M?ssbauer integrated until the team invoked deep sleep at 7p.m. local solar time, and was restarted after deep sleep at 7a.m. the next sol.
sol 163: Rover engineers stopped the M?ssbauer then successfully opened and closed the alpha particle X-ray spectrometer doors for diagnostic purposes. The rover arm was then stowed and the rover began a two-sol panoramic camera science survey of areas upslope from our current position.