* Astronomy

OPPORTUNITY UPDATE:  Farewell, "Victoria"! - sol 1634-1640, August 28-September 03, 2008:

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 colour 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-colour images of Isle Royale, using all 13 colour 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 metres.

OPPORTUNITY UPDATE:  Opportunity Eyes Challenges Ahead - sol 1614-1620, August 8-14, 2008:

Opportunity faces several challenges on the way out of "Victoria Crater" but continues to make steady progress. The first of these is a traverse of approximately 10 metres across a sandy, 17-degree slope. Opportunity is more than halfway through that part of the journey. The next is a drive across 30 to 50 metres, depending on the route taken, of rocky outcrop. The final leg of the climb will require Opportunity to cross the ripple surrounding the alcove known as "Duck Bay."
Because Opportunity is facing the threat of a drive-motor failure on the left front wheel, the engineering team has been working on pseudo-"Mars time" for the past week to take advantage of extra drive opportunities.
Opportunity remains healthy, with all subsystems performing as expected as of the downlink of information from NASA's Odyssey orbiter on sol 1620 (Aug. 14, 2008).

Sol-by-sol summary:
In addition to measuring daily, dust-related changes in atmospheric clarity with the panoramic camera, Opportunity completed the following activities:

Sol 1614 (Aug. 8, 2008): Opportunity took offset, thumbnail images of the sky with the panoramic camera for calibration purposes. With the navigation camera, Opportunity acquired images and six, time-lapse, movie frames in search of clouds. Just before and after ending the day's drive, Opportunity took rearward-looking images with the hazard-avoidance cameras. The rover relayed data to NASA's Odyssey orbiter for transmission to Earth.

Sol 1615: In the morning, Opportunity took six, time-lapse, movie frames in search of clouds with the navigation camera and monitored dust on the rover mast. Opportunity acquired image mosaics of targets dubbed "Dawson" and "Barrell" using the panoramic camera. The rover relayed data to Odyssey to be transmitted to Earth.

Sol 1616: Opportunity drove 3.05 metres, stopping mid-drive to acquire images with the navigation camera. The rover acquired images of the surface next to its wheels with the hazard-avoidance cameras as well as two post-drive image mosaics -- a 2-by-1 and 5-by-1 panel -- of its surroundings with the navigation camera.

Sol 1617: In the morning, Opportunity completed a survey of rock clasts with the panoramic camera. Before sending data to Odyssey, the rover acquired images with the rear hazard-avoidance cameras.

Sol 1618: Opportunity acquired a 2-by-2 mosaic of images with the panoramic camera before driving another 3.17 metres. Just before and after ending the drive, Opportunity took images with the hazard-avoidance and navigation cameras.

Sol 1619: Opportunity took spot images of the sky for calibration purposes with the panoramic camera. After completing the daily assessment of atmospheric dust, Opportunity drove 1.04 metres. Just before and after ending the drive, the rover took images with the hazard-avoidance cameras of the ground near its wheels. After the drive, Opportunity acquired a 2-by-1 and a 5-by-1 image mosaic of its new location with the navigation camera. The rover communicated with Odyssey before going to sleep.

Sol 1620 (Aug. 14, 2008): In the morning, Opportunity acquired six, time-lapse, movie frames in search of clouds with the navigation camera as well as spot images of the sky with the panoramic camera. Later in the day, Opportunity took thumbnail images of the sky and completed a sky survey at high Sun with the panoramic camera. Plans for the following morning called for Opportunity to acquire panoramic-camera images of a rock target known as "du Toit."

Odometry:
As of sol 1619 (Aug. 13, 2008), Opportunity's total odometry was 11,735.83 metres.

Image taken by the Opportunity Rover on Sol 1631


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Credit NASA

Image taken by the Opportunity rover on Sol 1615


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Credit: NASA