Mars Exploration Spirt Rover Update – October 9-15, 2008
SPIRIT UPDATE: Getting Ready to Make the Next Move – sol 1695-1701, October 09-15, 2008:
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.
Sol-by-sol summary
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.
Odometry:
As of sol 1700 (Oct. 14, 2008), Spirit’s total odometry remained at 7,528.0 meters (4.7 miles).
