One Year On Mars, Not Checking Out Heat Shield

SPIRIT UPDATE: Spirit Celebrates Year Anniversary on Mars – sol 346-352, January 06, 2005

Spirit landed on Mars one year ago on Jan. 3, 2004, (Pacific Time) and is still healthy and going strong!

On sol 346, Spirit confirmed that it had dumped a potato-shaped rock that had been plaguing Spirit’s right rear wheel. Confirmation came by comparison of before and after images from the rear hazard-avoidance camera. The total distance driven on sol 346 was 0.33 meters (1.08 feet).

On sol 347, Spirit observed selected targets with its panoramic camera and miniature thermal emission spectrometer.

On sol 348 took pictures of a target called “Dreaming” with the microscopic imager, and then did a tool change to the alpha particle X-ray spectrometer. Spirit also made some remote-sensing observations of targets with holiday theme names.

On sol 349, Spirit did a tool change to the Mössbauer spectrometer and made more observations.

On sol 350, the plan was to drive Spirit 5 meters (16 feet) towards the rock named “La Brea.” However, the drive achieved less than a meter (3 feet) due to slippage.

On sol 351, Spirit attempted to drive again. This drive involved a series of rearward and forward arcs to get to more favorable terrain. Most of the slip occurred during the forward arcs. The estimated slip on the rearward arcs was 15 per cent, but the estimated slip on the forward arcs was 39 per cent. The destination, a rock called “Dick Clark,” was still about 4.2 meters away (14 feet).

On sol 352, the incomplete drive on the previous sol had left the rover team with a rock of interest right between the rover’s front wheels. Spirit examined a target called “Bubbles” with its microscopic imager, then changed tools to the alpha particle X-ray spectrometer. Spirit also made sky observations with its thermal emission spectrometer and panoramic camera. Sol 352 ended on Dec. 29.

OPPORTUNITY UPDATE: Sizing Up the Heat Shield – sol 325-332, January 05, 2005

Opportunity is healthy and has reached the site where its heat shield hit the ground. The rover will make detailed observations of the heat shield’s remains, weather permitting. The rover experienced its first dust storm since landing, which has affected the amount of energy Opportunity gets each sol. When the rover landed nearly one Earth year ago, a dust storm was subsiding and the atmosphere had an opacity of 0.9 (the higher the number, the murkier the skies). Since then, the opacity had improved significantly and was roughly 0.5 on sol 327. On sol 328 the opacity jumped to 0.6 then to 0.8, 1.2, and 1.25 on sols 329-331. As of sol 332 it is at 1.2 and dropping. Images from Mars Global Surveyor orbiter have confirmed the presence of a few small dust storms in the region. The energy intake has decreased roughly 30 percent, leaving Opportunity with less energy for operations and communications but still enough, with comfortable margin, to continue with the plan to investigate the heat shield remains. The dust storms will be monitored carefully using the rover’s own instruments and images from Mars Global Surveyor. The team will also be walking through low-energy contingencies should they become necessary.

Sol-by-sol summaries:

On sol 325, Opportunity drove 27 meters (about 89 feet) backward, to “West Point.” It imaged the heat shield debris field from that vantage point. The engineers choose to occasionally drive the rover backward for convenience and to keep the wheel-motor lubrication more evenly distributed.

Sol 326 was the second sol of a two-sol plan. This sol was spent imaging the heat shield debris field.

On sols 327 to 329, the Mössbauer spectrometer was placed on the compositional calibration target for a series of observations over the Earth weekend. This is done periodically to calibrate the Mössbauer instrument. The rover continued routine atmospheric observations and remote sensing of the heat shield debris field.

On sol 330, Opportunity used its panoramic camera to take images of the heat shield debris field, then drove 15 meters (about 49 feet) to a location called “South Point” for another look at the debris field.

On sol 331, Opportunity drove roughly 10 meters (33 feet) to approach the flank portion of the heat shield remains. The heat shield broke into two main piece when it hit the ground. The flank is the smaller of those portions.

On sol 332, which ended on Dec. 30, the rover made its final approach to the flank portion of the heat shield wreckage in preparation for close-up inspection of the heat shield material over the New Year’s holiday weekend. The drive brought Opportunity’s odometer total to 2,051 meters (1.27 miles).