Daily Updates - August 3, 2004
Opportunity Status at end of sol 181-185
Opportunity is completing an intensive survey of the "Karatepe" region that began 50 sols ago when the rover first ventured into "Endurance Crater." The rover currently sits about 20 meters (about 66 feet) inside the stadium-sized crater. The investigation at an area dubbed "Inuvik" at a target called "Tuktoyuktuk" (named for a small village in the Canadian arctic) will likely be the rover's last in this region. The rover planning team is contemplating the next traverse which will move Opportunity around the interior of the crater, first to some outcroppings dubbed the "Arctic Islands," then possibly to "Burns Cliff," roughly 80 meters (about 262 feet) from the rover's current position. Opportunity continues to perform very well, a testament to all those who worked so hard to get it to Mars and to those who operate it daily.
Some concerns that are being addressed are slippage, an error message from the microscopic imager and pointing errors with the front hazard-avoidance cameras.
The drive on sol 185 included a short backup, during which the rover experienced a 40 percent slip. Typical slips when driving uphill have been in the 15- to 20-percent range. More evaluation of what happened on this and other drives will be needed before any general conclusions can be made about traversability in this region. The overall slope in this area is 15 degrees, which is 10 degrees below the general threshold of concern for rocky terrain. Sol 185 ended on Aug. 1.
There have been four instances of a warning message in the last ten sols that indicate a problem getting data from the microscopic imager. The messages indicate that the data was corrupted, and that a retry was necessary to receive the data without error. In all cases, the retry succeeded in transferring the data. This problem has not been seen before on either vehicle.
The new front hazard-avoidance camera models may need some more tweaking. Pointing errors were greater than expected on two recent placements of the instrument deployment device (robotic arm). The error is such that rover planners can still confidently place the instruments, provided that a 2-centimeter (0.8-inch) offset can be safely tolerated. If more precision is needed, planners must first use the microscopic imager to survey the target, then wait one sol before placing any instruments.
Sol highlights:
181 - A very accurate drive placed the target "Mackenzie" squarely in Opportunity's work volume.
182 - A two-hour hour rock abrasion tool (RAT) operation at Mackenzie was followed by an observation with the Moessbauer spectrometer. On this sol, Opportunity took panoramic camera images during the abrasion tool operation for the first time. The images were normal. Being able to use the panoramic camera and abrasion tool in parallel is one of the items on the "teach your dog new tricks" list, an effort to help the rover multi-task. The rover went into deep sleep this sol.
183 - Opportunity completed the Moessbauer observation of the RAT hole at Mackenzie, then placed the alpha particle X-ray spectrometer on the hole for an observation to start at 4 a.m. the next morning. (This instrument works best when very cold).
184 - The rover took microscopic imager pictures of the Mackenzie RAT hole, stowed the arm, then backed up to observe the hole with the panoramic camera and the miniature thermal emission spectrometer. The rover drove forward roughly 8 meters (26 feet) to Inuvik, using visual odometry to gauge the amount of slip. The drive left Opportunity to the right of the intended location because the rover slipped towards the fall line of the crater, causing the vehicle to effectively arc to the right. Deep sleep was invoked.
185 - Opportunity performed a short maneuver to get Tuktoyuktuk into the arm's work volume. Slippage was greater than expected during the uphill part of that move, so Opportunity ended up with only the upper part of the target in the work volume. That turned out to be good enough to perform a full set of arm work, which is planned for sols 186 through 188. The rover took panoramic camera images of the area between Inuvik and the Arctic Islands for the purposes of evaluating that drive. It turned the inertial measurement unit on again during the afternoon communications relay. This is another item on the "new tricks" list that, if successful, will allow rover planners to turn the vehicle during communication passes to optimize the data return. The rover again used deep sleep.
Opportunity Daily Update Archive
