Spirit tilts right, Opportunity prepares to welcome Phoenix

Scarcely a pinball wizard on Earth could tilt the machine nearly 30 degrees without ending play, yet engineers tilted NASA's Spirit rover 29.9 degrees and completed the robotic equivalent of a one-armed toe-touch to test its stability.

The rover remained in play, racking up scientific data points after remaining perfectly balanced even while pressing the ground with the Möessbauer spectrometer at the end of its robotic arm.
During the past week, Spirit began work on a 360-degree, full-color panorama of the rover's winter surroundings as viewed from the north edge of the elevated, volcanic plateau known as "Home Plate." The resulting mosaic of high-resolution images, to be acquired during approximately 60 individual pointings of the panoramic camera, will be nicknamed the "Bonestell panorama" in honor of Chesley Bonestell (pronounced BON-es-tell), a science fiction illustrator and designer. (Last year's spectacular image mosaic of Spirit's winter haven was called the "McMurdo panorama.")

Spirit took microscopic images of dust that has settled out of the Martian sky onto the solar panels. The rover also made two attempts to complete the first of a two-part process for brushing the surface of a rock target dubbed "Wendell Pruitt" with the rock abrasion tool, another of the instruments on the rover's robotic arm.

Because the results were inconclusive after the first try, Spirit's handlers decided to have the rover repeat the procedure, known as a "grind scan," during which the rover locates the surface by touching it with the brush and the grinding bit, two days later. The second attempt was successful, clearing the way for actual brushing of Wendell Pruitt.

Spirit is healthy and all subsystems are performing as expected.

Opportunity completed the first leg of a two-part drive toward an area of scientific interest known as "Gilbert" that involved moving backward in order to continue the drive without running into some unexpectedly deep soil to the rover's right. En route, Opportunity spent two Martian days acquiring compositional data from a rock exposure dubbed "Lyell-Exeter," measured argon gas in the Martian atmosphere, and conducted remote-sensing activities.

In addition, Opportunity tested relay communications in support of NASA's Phoenix mission, due to land on Mars in late May. The first test, with the European Space Agency's Mars Express spacecraft, took place on sol 1444 (Feb. 15, 2008) and was primarily a trial of a new command strategy to permit the orbiter to acquire a larger amount of data from the surface of Mars.

The second test was a possible relay through the NASA's Mars Reconnaissance Orbiter on sol 1446 (Feb. 17, 2008). This was an attempt to take advantage of an anomaly on the orbiter that turned off science instruments and placed the orbiter on standby to await instructions from Earth. The recovery timeline ended up not supporting this particular test.

The third, with Mars Express on sol 1449 (Feb. 20, 2008), was part of a series of tests to determine differences in performance when the orbiter receives data from directly overhead and when the orbiter receives data when not directly overhead.

Opportunity remains healthy, with all subsystems performing as predicted. On sol 1449 (Feb. 20, 2008), the rover had 447 watt-hours of power (100 watt-hours is the amount of energy needed to light a 100-watt bulb for 1 hour).

Assuming Opportunity successfully completes a planned drive on sol 1450 (Feb. 21, 2008), the rover will be in position to begin a full complement of scientific investigations of Gilbert.

Source: Jet Propulsion Laboratory
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