NASA Mars Rover Status Report 22 October 2004
SPIRIT UPDATE: Spirit investigating ancient rocks – sol 272-278, October 20, 2004
Spirit had a productive week investigating the rock “Tetl.” On sol 277, Spirit attempted a drive to the next rock target, “Uchben,” which means “ancient” in the old Mayan language. Halfway into that drive, Spirit experienced a repeat problem in the steering motor control system that engineers first saw on sol 265. Engineers repeated diagnostic tests for the problem on sol 278. Those tests showed that the electronics relay in question is still functional, but appears to operate intermittently. Spirit is otherwise healthy and is in a safe location.
On sol 272, Spirit took images with the microscopic imager to create a mosaic of Tetl’s layered rock face.
On sol 273, Spirit captured more microscopic images of Tetl’s layered face, then put the alpha particle X-ray spectrometer in place for an early morning observation.
On sol 274, Spirit woke up at 4:00 a.m. to start the alpha particle X-ray spectrometer observation. The alpha particle X-ray spectrometer stayed on until the start of normal morning atmospheric science observations. Spirit also used its miniature thermal emission spectrometer to observe nearby rocks named “Zackuk” and “Palenque,” which are possible future targets for in-depth observations. Later, Spirit changed tools on its robotic arm, placing the Mössbauer instrument on Tetl for an observation the next morning.
On sol 275, Spirit completed a 6-hour Mössbauer integration and performed daily atmospheric observations. This was the final sol of Spirit’s weekend plan and was purposely simple to enable the sequencing team to complete a 3-day plan on Friday.
On sol 276, Spirit restarted the Mössbauer instrument at 4:00 a.m. for another 10 hours of integration time on the same spot. Spirit also took a few final microscopic images of Tetl, then stowed the robotic arm in preparation for the next sol’s drive.
On sols 277 and 278, Spirit attempted a drive to Uchben, another layered rock roughly 6 meters (20 feet) northeast of Tetl. About 2.5 meters (8 feet) into the drive, the mobility software attempted to move a steering motor by first commanding open a relay (electronic switch) that releases a dynamic brake. The feedback from that command indicated that the relay was still closed, so the motor control software declared an error. Due to the error, the rover ignored that steering command and all subsequent driving commands. The root cause of the failed relay command is under investigation. A diagnostic test last run on sol 270 was repeated on sol 278, which ended on Oct. 14. That test showed that the steering motor’s dynamic brake relay can still be opened and closed, but does occasionally (5 out of 10 times) indicate that it is still closed after being commanded open.
More diagnostics tests are needed before the source of the problem can be positively identified. Until then, engineers will continue to drive, but will steer the rover in a tank-like fashion, not using the steering actuator in question.
Future plans are to clear the drive error and attempt another drive to Uchben on sol 281. Engineers are also planning to run more diagnostic tests starting on sol 282.
OPPORTUNITY UPDATE: Wave Goodbye to ‘Wopmay’ – sol 258-264, October 22, 2004
Opportunity’s health is excellent. Solar exposure continues to be very good. Opportunity spent its first night inside “Endurance Crater” on sol 134. To date, the rover has spent 130 sols in the crater, grinding 21 targets with the rock abrasion tool, performing 62 integrations with the Mössbauer spectrometer and 33 with the alpha particle X-ray spectrometer, and taking 115 observations with the miniature thermal emission spectrometer. Opportunity finally completed observations on the rock “Wopmay,” and is ready to begin its trek towards “Burns Cliff” on the way to exiting Endurance Crater.
Sol details:
On sol 258, Opportunity examined three targets (“Otter,” “Jenny,” and “Hiller”) on Wopmay with its microscopic imager. Each of the observations was designed to produce a mosaic. They relied on touching the instrument’s contact sensor to the uneven surface of Wopmay for each quadrant of each mosaic to ensure appropriate standoff distances for good focus.
Sols 259 through 261 were designed as a single three-sol weekend plan. During the morning of sol 259, arm operations continued with two more microscopic imager mosaics of the targets “Jet Ranger 2” and “Twin Otter.” In the early afternoon, Opportunity placed its alpha particle X-ray spectrometer in a hover position approximately 1 centimeter (0.4 inches) above Otter. After a couple of naps and miniature thermal emission spectrometer observations, the rover went into deep sleep until the next morning.
The first part of a reading with the alpha particle X-ray spectrometer over Otter was performed for three hours in the morning of sol 260. During the same period, the rover made navigation camera, panoramic camera, and miniature thermal emission spectrometer cloud observations, then snapped images with the navigation and panoramic cameras in the drive direction. While performing an atmospheric observation with the panoramic camera, Opportunity collected extra images of the sky close to the Sun to allow observations of the dust accumulation on the camera’s window.
In the early morning of sol 261, the reading with the alpha particle X-ray spectrometer resumed, continuing until about 11 a.m. local solar time and producing excellent spectra despite the standoff position of the sensor. Opportunity then collected Mössbauer data over Otter for another three hours. Several remote science observations were made over the course of the sol, including photometric measurements with the panoramic camera and targeted observations of Wopmay with the miniature thermal emission spectrometer and the panoramic camera observations.
On the morning of sol 262, Opportunity took a third photometric measurement and used the panoramic camera to study Wopmay, concluding the weekend plan. In the early afternoon, the rover made a final microscopic image of the target “Hercules” on Wopmay, then backed away as part of a plan to re-approach the back side of Wopmay for possible additional measurements. Navigation camera imagery of the back of Wopmay was collected in the afternoon, followed by extensive panoramic camera imaging the next morning. Unfortunately, due to slippage during the traverse, Opportunity didn’t reach its desired vantage point, and the target was not in view.
For sol 263, a decision was made to delete the panoramic camera imagery without downlinking it, since on board memory was tight and we already have complete coverage of the part of Wopmay captured. The new plan was to continue the rover’s drive toward the back of Wopmay, and repeat the imaging observations attempted in the sol 262 plan. But as Opportunity drove toward Wopmay, it encountered a hidden obstacle: a rock buried under the sand that resulted in 100 percent slip for a good part of the traverse. Once the rover was clear of the rock, it continued from a point much closer to Wopmay than anticipated. Rover planners estimated that, at the end of the traverse, Opportunity was within 30 centimeters (just under one foot) of Wopmay, uncomfortably close!
On sol 264, which ended on Oct 21, Opportunity backed away from Wopmay. The planned drive was 2.5 meters (8.2 feet) but the actual drive was 2.57 meters (8.4 feet). Opportunity is now in position to begin its drive toward Burns Cliff.
Total odometry after sol 264 is 1,638.57 meters (1.0181 mile)
