sol 1685-1689, September 28 - October 03, 2008:
Spirit is poised to begin making more "phone calls" to Earth and engineers are preparing to contact Spirit more frequently as a result of improving solar power input on Mars. Though Spirit's energy levels are still low, they are improving significantly as Martian winter gradually fades into spring. The rover will use some of the energy to let engineers and scientists know how things are going on Mars.
Spirit stays in touch by transmitting data at UHF frequencies to NASA's Odyssey orbiter. Odyssey sends it to Earth. On the other end of the line, engineers send new activity plans to Spirit using X-band transmissions from Earth that go directly to the rover's dish antenna. More frequent communication allows greater operational flexibility as the rover gradually returns to a normal planning schedule and prepares to drive again in mid- to late October.
Spirit's first post-winter drive will be short, just far enough to adjust the rover's position so its solar panels remain tilted toward the Sun as it moves higher in the sky. The goal is to have Spirit in the best possible position before solar conjunction -- the time of year when the Sun passes between Mars and Earth and temporarily prohibits communication.
Meanwhile, Spirit has been working hard to complete the full-color "Bonestell panorama" of the rover's winter surroundings. After a long hiatus caused by power limitations, Spirit resumed making measurements of argon gas in the Martian atmosphere.
Spirit is healthy, with all subsystems performing as expected as of sol 1686 (Sept. 30, 2008). Solar-array energy increased to 262 watt-hours (100 watt-hours is the amount of energy needed to light a 100-watt bulb for one hour). Skies remained clear, with tau, a measure of the amount of sunlight blocked by atmospheric dust, at 0.134. Historically, dust levels at this time of year have been higher. Rover operators are keeping close tabs on atmospheric dust because of its potential impact on the rover's power state.
Sol-by-sol summary
Spirit completed the following activities:
Sol 1685 (Sept. 28, 2008): Spirit listened for communications from Earth with the rover's low-gain antenna, checked for drift -- changes with time -- in the miniature thermal emission spectrometer, surveyed the sky and ground with the instrument, and measured atmospheric opacity caused by dust (tau) with the panoramic camera. Spirit monitored dust accumulation on the panoramic-camera mast assembly and acquired column 22, part 2, and column 24, part 2 of the so-called "Bonestell panorama," a full-color, 360-degree view of the rover's winter surroundings, created with all 13 color filters of the panoramic camera.
Sol 1686: Spirit received new instructions from Earth at X-band frequencies sent to the rover's high-gain antenna and spent three hours measuring argon gas in the Martian atmosphere with the alpha-particle X-ray spectrometer. Spirit relayed data to NASA's Odyssey orbiter to be transmitted to Earth.
Sol 1687: Spirit measured dust-related changes in atmospheric darkness with the panoramic camera and acquired column 23, part 2 and column 25, part 2 of the Bonestell panorama.
Sol 1688: Spirit checked for drift in the miniature thermal emission spectrometer, surveyed the sky and ground with the instrument, and measured atmospheric opacity caused by dust with the panoramic camera. Spirit acquired column 27, part 2 and column 26, part 2 of the Bonestell panorama. The rover supplemented panoramic-camera measurements of atmospheric dust with measurements from the navigation camera and acquired a four-frame movie in search of clouds with the navigation camera.
Sol 1689 (Oct. 3, 2008): Plans called for Spirit to measure dust- related changes in atmospheric darkness with the panoramic camera and acquire column 19, part 3 and column 21, part 3 of the Bonestell panorama. The rover was to assess atmospheric dust levels with the navigation camera and produce a four-frame, time-lapse movie of potential clouds passing overhead.
Odometry:
As of sol 1686 (Sept. 30, 2008), Spirit's total odometry remained at 7,528.0 meters (4.7 miles).
