* Astronomy

OPPORTUNITY UPDATE: Continuing the Move Away from 'Erebus' - sol 762-770, Mar 27, 2006:

Opportunity is healthy and making progress away from "Erebus Crater." This week the rover drove nearly 180 metres.

Sol-by-sol summaries:

Sol 762 (March 16, 2006): Opportunity started the sol in front of a long, flat trough and was able to drive just over 53 metres along this path.

Sol 763: The rover conducted atmospheric science and cloud observations.

Sol 764: Opportunity conducted targeted remote sensing, including panoramic camera images of "Red River Station" and "Kingfisher." It examined "Rush Springs" and "Red River Station" with the miniature thermal emission spectrometer. It also filmed three cloud movies at various times of day and did some other atmospheric science.

Sol 765: The rover drove 48.5 metres, first over a small ripple, then down a trough to a patch of outcrop.

Sol 766: The rover drove 34.6 metres, first down a trough, then crossing a few small ripples.

Sol 767: Opportunity drove approximately 44 metres over a few small ripples. Since there was no outcrop along the day's drive path, the team used more frequent slip checks. Before the drive, Opportunity acquired panoramic camera images of some nearby outcrop.

Sol 768: The Odyssey orbiter went into safe mode before Opportunity's afternoon UHF relay pass, so the team didn't have any information on how the rover performed on sol 767. For sol 768 the team planned a 70-minute direct-to-Earth communication session. Mars is getting farther from Earth, and even with a Deep Space Network dish antenna 34 metres in diameter, the slow downlink rate yielded only 6 megabits of data. However, this was enough to indicate that the planned activities on sol 767, including the drive, had been completed successfully.

Sol 769: Odyssey was still recovering from safe mode. Since the UHF downlink capability was unavailable, the planned activities for Opportunity for the day were only to collect two tau readings. (Tau is a measure of atmospheric opacity. Determining it requires very little data volume.) The rover did not use the deep-sleep mode.

Sol 770 (March 24, 2006): The sol's activities were planned knowing that the day could be the earliest that the rovers might regain communication-relay support from Odyssey. The team is planned several tau observations and a scan of sky and ground by the miniature thermal emission spectrometer. Opportunity did use the deep sleep mode.

Total odometry as of sol 768 (March 22, 2006): 6,908 metres.

OPPORTUNITY UPDATE: Hawkeyeing from the 'Half Pipes' - sol 751-756, Mar 11, 2006:

Opportunity is healthy and making its way south along the "Payson" outcrop of "Erebus Crater." The traverse paths are known within the team as "half-pipes," after the popular Olympic event. Last week Opportunity drove along one half-pipe, collecting high-resolution panoramic camera images of the outcrop. (The team calls this "scoot and shoot"). The rover has now left this path, and the team has planned a drive to the next half-pipe. Depending on traversability, Opportunity will either continue its scoot-and-shoot outcrop imaging campaign over the weekend, or start down the road to "Victoria Crater."

Sol-by-sol summaries:

Sol 751 (March 5, 2006): Opportunity drove a short bump, took mid-drive panoramic camera images of the outcrop, then drove about 8 metres along the "half-pipe."

Sol 752: The rover did untargeted remote sensing this sol, including atmospheric science and systematic foreground studies with the navigation camera and the miniature thermal emission spectrometer. Systematic foreground studies means gathering a set of consistent observations of different objects right in front of the rover.

Sol 753: Opportunity took pre-drive panoramic camera images of a cobble, drove 4 metres, imaged the outcrop, then drove about 11 metres out of the first half-pipe towards the next one. It also acquired post-drive imaging.

Sol 754: Opportunity conducted systematic foreground studies with the panoramic camera and the miniature thermal emission spectrometer. The rover also did some atmospheric science.

Sol 755: Opportunity drove about 19 metres to the edge of the half-pipe and acquired post-drive imaging to determine traversability.

Sol 756 (March 10, 2006): The plan for the sol is to conduct atmospheric science, including an attempt to observe clouds.

Total odometry as of sol 753 (March 7, 2006): 6645.57 metres.

Sol 743


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OPPORTUNITY UPDATE: Opportunity Continues to Skirt Erebus Crater - sol 735-743, Feb 24, 2006:

After completing work at the outcrop called "Olympia," Opportunity proceeded around the western edge of "Erebus Crater" toward an outcrop dubbed "Payson." After performing diagnostic tests on Martian day, or sol, 735 (Feb. 17, 2006), the rover team decided to increase rotor resistance from 65 ohms to 80 ohms for stowing and unstowing the robotic arm. Opportunity successfully stowed and unstowed the arm on both sols 740 and 741. As long as the robotic arm remains in calibration, the higher resistance value provides no additional risk.

Sol-by-sol summaries:

Sol 735 (Feb. 17, 2006): Opportunity conducted diagnostic activities on its robotic arm, making small movements of the shoulder joint with rotor resistance set at 75 ohms. If the arm were to fault out during any of the motions, the rover would clear the fault and re-set the resistance first to 80 ohms, and then to 85 ohms. However, the arm completed all motions successfully with rotor resistance set at 75 ohms.

Sol 736: The rover team attempted for a second time to send instructions via X-band frequencies for a drive to a target called "Zane Grey," but a Deep Space Network transmitter was down. The team did receive data from Opportunity over the same communications link.

Sol 737: Rover planners sent instructions to Opportunity for the second two days of the original three-day plan. Opportunity made atmospheric observations and measurements of the intensity of astronomical objects.

Sol 738: Opportunity continued to make remote atmospheric observations and photometric measurements.

Sol 739: Opportunity completed planned photometric measurements.

Sol 740: Opportunity began the planned drive to Zane Grey, stowing and unstowing the robotic arm with rotor resistance set at 80 ohms on the shoulder joint that controls compass direction. The rover halted after moving 21 centimetres when the right middle wheel reached the maximum current allowed. Motor currents on the other wheels remained nominal. Rover planners reduced the current limits after leaving "Purgatory Dune" to help prevent another imbedding event.

Sol 741: Opportunity drove 34.5 metres closer to the Payson outcrop after rover drivers set the current limits back to nominal values. Motor currents at the start of the drive were a bit higher than normal but dropped closer to normal values as the drive progressed.

Sol 742: Science team members planned to have Opportunity drive about 40 meters closer to "Payson" and acquire images from a distance of 20 metres over the weekend.

As of sol 742 (Feb. 24, 2006), Opportunity's total odometry was 6553.93 metres.