In recent weeks, increasing solar power has enabled Spirit to complete more science activities. Spirit has finished the 360-degree, full-color view of its winter surroundings, known as the "Bonestell panorama," and acquired extra frames at super resolution to enhance details in the imagery. The rover also has documented seasonal changes in the atmosphere by measuring argon gas with the alpha-particle X-ray spectrometer.

The tradeoff has been that by funneling most available power into science activities, Spirit has not had much power for sending data to Earth. That is about to change, because Spirit's on-board memory is nearly full. Instead of sending data only every fourth day, Spirit will begin relaying data every day to NASA's Odyssey orbiter for transmission to Earth.

Rover operators will use the data to plan Spirit's first, post-winter drive to adjust the rover's position to keep the solar panels facing the Sun. The move will put the rover in optimum position before solar conjunction, when Earth and Mars will be on opposite sides of the Sun and communication will not be possible. Solar conjunction will take place on Martian days, or sols, 1745-1760 (Nov. 29-Dec. 15, 2008).

Meanwhile, Spirit is healthy, with all subsystems performing as expected as of sol 1700 (Oct. 14, 2008). Solar-array energy has been 242 watt-hours (100 watt-hours is the amount of energy needed to light a 100-watt bulb for one hour). After weeks of remarkably clear skies, atmospheric opacity or tau, a measure of the decrease in sunlight caused by atmospheric dust, has risen slightly to 0.294. Atmospheric dust levels remain low, but are beginning to trend upward and affect solar power levels. This increase is expected, as it has occurred at this time of year in each of the previous three Martian years.

The dust factor -- the percentage of light penetrating dust on Spirit's solar arrays -- has remained steady. Only 32 percent of the sunlight reaching the arrays penetrates the dust to generate electricity.

In addition to making daily measurements of the amount of atmospheric dust preventing sunlight from reaching the rover's solar arrays, Spirit completed the following activities:

Sol 1695 (Oct. 9, 2008): Spirit checked for drift (changes with time) in the miniature thermal emission spectrometer, surveyed the sky and ground with the instrument, did survey work with the panoramic camera, and surveyed a surface target dubbed "Jules Verne" with the miniature thermal emission spectrometer.

Sol 1696: Spirit surveyed the sky and ground with the miniature thermal emission spectrometer and made some finishing touches to the lower edge of the full-color, 360-degree view of the rover's winter surroundings by acquiring 3 panels of images known as "Bonestell lower tiers" 1, 2, and 3.

Sol 1697: Spirit used the miniature thermal emission spectrometer to survey the sky, the ground, and a target known as "Stapledon." Spirit parked the panoramic camera mast assembly with the panoramic camera pointed below the horizon to minimize dust accumulation.

Sol 1698: Spirit took spot images of the sky for calibration purposes with the panoramic camera and spent much of the day recharging the battery.

Sol 1699: Spirit surveyed the sky at different elevations as well as the ground with the miniature thermal emission spectrometer and used the panoramic camera to survey the horizon and take thumbnail images of the sky on the rover's right (starboard).

Sol 1700: Spirit surveyed the sky and ground with the miniature thermal emission spectrometer and took spot images of the sky with the panoramic camera. Spirit relayed information from Mars to NASA's Odyssey orbiter for transmission to Earth.

Sol 1701 (Oct. 15, 2008): Spirit surveyed the sky and ground with the miniature thermal emission spectrometer and monitored dust accumulation on the panoramic-camera mast assembly.

As of sol 1700 (Oct. 14, 2008), Spirit’s total odometry remained at 7,528.0 meters (4.7 miles).

Opportunity got some good vibrations going this week while trying to remove dust from the mirror of the miniature thermal emission spectrometer, an instrument that measures temperatures and detects minerals from a distance. Using low-level motor commands on the rover's 1,680th sol, or Martian day of exploration (Oct. 14, 2008), Opportunity created a short vibration to shake the instrument's external scan mirror. It was the first time Opportunity attempted such a feat, and scientists are analyzing the results.

Opportunity also got into position for the final imaging campaign at "Victoria Crater," driving onto a promontory known as "Cape Agulhas." From here, the rover acquired images of rocks exposed in a promontory known as "Cape Victory."

Other remote-sensing highlights of the week included measurements of argon gas in the atmosphere on sols 1675, 1677 and 1680 (Oct. 9, 11, and 14, 2008) and color images of an area of bedrock in front of the rover nickamed "Savu Sea" on sol 1676 (Oct. 10, 2008). Opportunity took images of a weathered rock exposure known as "Dauphin," surveyed the horizon, and took spot images of the sky for calibration purposes. The rover monitored dust on the panoramic-camera mast assembly, searched for clouds, and studied the atmosphere.

Opportunity remains healthy, with all subsystems performing as expected as of Martian day, or sol, 1680 (Oct. 14, 2008). Power has been averaging 616 watt-hours during the past week (100 watt-hours is the amount of energy needed to light a 100-watt bulb for one hour.)

Sol-by-sol summary

Besides measuring daily, dust-related changes in atmospheric clarity with the panoramic camera, Opportunity completed the following activities:

Sol 1674 (Oct. 8, 2008): During the day's drive, Opportunity acquired a 2-by-1 panel of images with the navigation camera. After the drive, Opportunity acquired a 5-by-1 tier of navigation-camera images, a 4-by-1 tier of forward-looking, panoramic-camera images, and a 5-by-1 tier of rearward-looking, navigation-camera images.

Sol 1675: In the morning, Opportunity surveyed the horizon with the panoramic camera. The rover took thumbnail images of the sky for calibration purposes with the panoramic camera and scanned the sky for clouds by acquiring four time-lapse images with the navigation camera. After relaying data to NASA's Odyssey orbiter to be transmitted to Earth, Opportunity measured atmospheric argon with the alpha-particle X-ray spectrometer.

Sol 1676: Opportunity acquired full-color images, using all 13 filters of the panoramic camera, of Savu Sea. The rover continued driving, acquiring a 2-by-1 panel of forward-looking images along the way with the navigation camera. After the day's drive, Opportunity took a 5-by-1 tier of images with the navigation camera, a 4-by-1 panel of images of the road ahead with the panoramic camera, and a 5-by-1 tier of rearward-looking images with the navigation camera.

Sol 1677: In the morning, Opportunity monitored dust accumulation on the rover mast. After sending data to Odyssey, Opportunity integrated measurements of atmospheric argon with the alpha-particle X-ray spectrometer.

Sol 1678: Opportunity acquired systematic, full-color images of the foreground with the panoramic camera. The rover spent much of the day recharging the battery.

Sol 1679: Opportunity took morning spot images of the sky for calibration purposes and a 2-by-1 panel of pre-drive images of Dauphin with the panoramic camera. The rover drove to the next imaging location on Cape Agulhas, acquiring a 2-by-1 panel of forward-looking images before ending the drive with the navigation camera. After the drive, Opportunity acquired a 3-by-1 standard tier and a 7-by-1 rearward-looking tier of images with the navigation camera. The rover transmitted data to Odyssey.

Sol 1680 (Oct. 14, 2008): Opportunity took spot images of the sky with the panoramic camera and searched for morning clouds with the navigation camera by pointing it skyward and acquiring a six-frame, time-lapse movie. Opportunity acquired a 3-by-1 panel of color images of Cape Victory with the panoramic camera and a high-resolution view of the rover deck with the navigation camera. The rover acquired images with the navigation camera to provide context for measurements by the miniature thermal emission spectrometer. Before shaking the spectrometer's mirror, Opportunity checked for drift (changes with time) in the instrument, conducted an operational test, and surveyed the ground and sky with the instrument for comparison purposes. Finally, Opportunity conducted the shake test, operating the motor in such a way as to vibrate the mirror in an effort to shake off dust. After sending test results and other data to Odyssey, Opportunity measured argon gas in the atmosphere with the alpha-particle X-ray spectrometer.

Odometry

As of sol 1679 (Oct. 13, 2008), Opportunity's corrected total odometry was 12,362.95 meters (7.68 miles).