Spirit continues to conserve power during the waning Martian winter while performing light science activities. As power permits, Spirit continues to acquire the individual frames of an image mosaic known as the "Bonestell panorama," which will portray a full-color view of the rover's winter outpost.

Spirit is healthy, with all subsystems performing as expected as of the most recent report from Mars sent by NASA's Odyssey orbiter on sol 1658 (Sept. 1, 2008). Solar-array energy had increased slightly from 235 to 245 watt-hours (100 watt-hours is the amount of energy needed to light a 100-watt bulb for one hour). Tau -- a measure of atmospheric opacity caused by suspended dust -- dropped from 0.274 to 0.218, meaning the skies were slightly clearer.

Sol-by-sol summary

In addition to taking daily measurements of dust-related changes in atmospheric opacity (tau), Spirit completed the following activities:

Sol 1657 (Aug. 31, 2008): Spirit acquired column 13, part 1 of the so-called "Bonestell panorama" of the rover's winter surroundings, using all 13 color filters of the panoramic camera.

Sol 1658: Spirit relayed data from Mars to NASA's Odyssey orbiter to be transmitted to Earth.

Sol 1659: Spirit received new instructions from Earth via the rover's high-gain, X-band antenna.

Sol 1660: Spirit recharged the batteries.

Sol 1661: Spirit recharged the batteries.

Sol 1662 (Sept. 5, 2008): Spirit recharged the batteries.

As of sol 1658 (Sept. 1, 2008), Spirit’s total odometry remained at 7,528.0 meters (4.7 miles).

Opportunity has completed one of the most fantastic scientific campaigns of the Mars Exploration Rover mission -- the interior investigation of "Victoria Crater." After spending more than 340 Martian days, known as sols -- almost one Earth year -- inside the crater, Opportunity climbed back out on sol 1634 (Aug. 28, 2008). To do so, Opportunity retraced the wheel tracks the robotic geologist had made while crossing a large sand ripple and entering Victoria on the slopes of an alcove known as "Duck Bay."

From the crater rim, Opportunity gave a final salute to Victoria, raising its robotic arm on sol 1639 (Sept. 2, 2008) and taking a snapshot of its shadow with the front hazard-avoidance cameras. The rover completed the salute by swinging the arm at its elbow joint back to the starting position.

Opportunity then got into position to practice using an ailing shoulder joint on the robotic arm. The shoulder joint had begun showing signs of degradation on sol 1502 (April 15, 2008). Rover operators selected the large sand ripple at the lip of Victoria Crater as an opportune target. There, the rover will practice learning to use the arm again.

Remote sensing highlights of the week included taking images of the tracks Opportunity left behind on the plains more than a year ago as well as color images of a nearby cobble called "Isle Royale." The rover also acquired images of a planned study area known as "Bright Spot" because of the large amount of sunlight reflected from its surface. Along the way, Opportunity continued to study the Martian atmosphere and clouds.

Opportunity is healthy, with all subsystems performing as expected as of the most recent transfer of information from NASA's Odyssey orbiter on sol 1640 (Sept. 3, 2008). Power has been excellent throughout this period, averaging about 621 watt-hours (enough energy to light a 100-watt bulb for more than 6 hours).

Sol-by-sol summary

Each Martian day, or sol, Opportunity measured dust-related changes in atmospheric clarity with the panoramic camera. In addition, Opportunity completed the following activities:

Sol 1634 (Aug. 28, 2008): While driving, Opportunity took snapshots of its journey. After the day's drive, the rover acquired images of the surrounding terrain and the surface near its wheels with the navigation and hazard-avoidance cameras. After relaying data to the Odyssey orbiter for transmission to Earth, Opportunity measured argon gas in the Martian atmosphere with the alpha-particle X-ray spectrometer.

Sol 1635: Opportunity searched for morning clouds with the navigation camera, acquiring six, time-lapse frames for a movie.

Sol 1636: Upon awakening, Opportunity acquired another six-frame, time-lapse movie in search of clouds with the navigation camera. The rover monitored dust accumulation on the panoramic-camera mast assembly and took images of the ripple at the lip of Victoria Crater with the panoramic camera. Opportunity took full-color images of Isle Royale, using all 13 color filters of the panoramic camera. After relaying data to Odyssey, Opportunity spent 5 hours and 20 minutes measuring argon gas in the atmosphere using the alpha-particle X-ray spectrometer.

Sol 1637: After the day's drive, Opportunity completed a "get fine attitude," during which the rover compared its precise location relative to the Sun with the position indicated by the on-board, inertial measurement unit. Following the drive, Opportunity took images with the hazard-avoidance and navigation cameras. The rover acquired a full, 360-degree panorama of the area with the navigation camera. After communicating with Odyssey, Opportunity went into a deep sleep.

Sol 1638: In the morning, Opportunity surveyed the horizon with the panoramic camera. After sending data to Odyssey, the rover went into a deep sleep.

Sol 1639: Before beginning the day's drive, Opportunity took images of "Bright Patch Two" with the panoramic camera. Opportunity approached the large sand ripple on the rim of Victoria and took post-drive images with the hazard-avoidance and navigation cameras. After relaying data to Odyssey, the rover measured atmospheric argon with the alpha-particle X-ray spectrometer. Opportunity then went into a mini-deep sleep.

Sol 1640 (Sept. 3, 2008): Opportunity acquired more images of Bright Patch Two as well as a 360-degree panorama of the area with the navigation camera. After sending data to Odyssey, the rover went into a deep sleep.

Odometry

As of sol 1639 (Sept. 2, 2008), Opportunity’s estimated total odometry was 11,781.51 meters (7.32 miles).