Spirit Begins Driving Uphill
Pasadena CA (SPX) Nov 11, 2008 With the Sun moving higher in the sky, Spirit's solar panels must move in the same direction to maximize their exposure to sunlight. To achieve optimal solar input, the panels still must tilt to the north, but not as steeply as before. To change the tilt, rover drivers have begun moving Spirit back upslope toward the top of "Home Plate." Their goal is to reduce the rover's northerly tilt from 30 degrees to 20 degrees. The change in tilt is vital, as Spirit is seeing the lowest energy levels of the mission. On Martian day, or sol, 1713 (Oct. 27, 2008), solar-array energy dropped to 207 watt-hours (that's enough energy to light a 100-watt bulb for slightly longer than two hours). The drop in energy was partly due to an increase in atmospheric dust believed to be related to distant dust storm activity. The same day, dust-related loss of visibility, known as Tau, reached a high of 0.69 before dropping to 0.60 on sol 1715 (Oct. 29, 2008). Because of the limited solar energy, the energy used for driving comes, in part, from the rover's batteries. As solar energy improves, Spirit will have to dip less into the batteries for driving. Fortunately, temperatures are warmer now than in the depths of winter. As a result, the dip in battery reserves is not nearly as great as it would have been if Spirit also required more battery power for heating. So far, rover drivers are pleased with Spirit's progress. The rover completed three upslope drives to achieve a northerly tilt of 21.8 degrees. Rover operators hope that a couple more budges will give Spirit a northward tilt of 20 degrees. Eventually, if Spirit can drive all the way back on top of Home Plate, the rover will save a significant amount of time while heading out on the next science campaign. If necessary, Spirit still has the option of driving downslope. Spirit is healthy, with all subsystems performing as expected as of sol 1715 (Oct. 29, 2008). Sol-by-sol summary In addition to measuring dust-related changes in atmospheric clarity each day with the panoramic camera and relaying data to Earth each evening via NASA's Odyssey orbiter, Spirit completed the following activities: Sol 1709 (Oct. 23, 2008): Spirit checked for drift (changes with time) in the miniature thermal emission spectrometer and surveyed the sky and ground with the instrument. Spirit then began inching uphill, and after the drive, took a single-frame image to document progress with the navigation camera. Sol 1710: Spirit surveyed the horizon with the panoramic camera, drove, and acquired images with the hazard-avoidance cameras as well as a quarter-frame image of the spacecraft deck with the panoramic camera. Sol 1711: Spirit checked for drift (changes with time) in the miniature thermal emission spectrometer and completed a mini-survey of the sky and ground with the instrument. Sol 1712: Spirit monitored dust on the panoramic-camera mast assembly and recharged the batteries.. Sol 1713: Spirit checked for drift (changes with time) in the miniature thermal emission spectrometer and completed a mini-survey of the sky and ground with the instrument. Spirit drove a bit farther upslope. Sol 1714: Spirit acquired a single-frame, post-drive image with the navigation camera as well as images with the hazard-avoidance cameras. Sol 1715 (Oct. 29, 2008): Spirit checked for drift (changes with time) in the miniature thermal emission spectrometer and completed a mini-survey of the sky and ground with the instrument. The rover then calibrated the spectrometer and began inching upslope again. After the drive, Spirit took a single-frame image with the navigation camera as well as images with the hazard avoidance cameras. Odometry: As of sol 1715 (Oct. 29, 2008), Spirit's total odometry remained at 7,528.42 meters (4.68 miles). Share This Article With Planet Earth
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Opportunity Takes A Victory Lap Pasadena CA (SPX) Oct 14, 2008 A journey of 7.5 miles began with a partial victory lap around "Victoria Crater," as Opportunity headed south toward enormous "Endeavour Crater." Partway around the circuit, Opportunity passed the 7.5-mile mark of the mission. In metric terms, the rover began a 12,000-meter, cross-country trek by ending a similar 12,000-meter journey across uncharted terrain and in and out of craters. |
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