Mars Rover Team Plays It Safes With Spirit

The images combined into this mosaic were taken by Spirit's navigation camera during the rover's 746th, 748th and 750th Martian days, or sols (Feb. 7, 9 and 11, 2006).

With the Martian winter closing in, controllers working with Spirit have decided to play it safe for the time being, rather than attempt to visit the far side of Home Plate in search of rock layers that might show evidence of a past watery environment. This feature has been one of the major milestones of the mission.

Though it is conceivable that rock layers might be exposed on the opposite side, sunlight is diminishing on the rover's solar panels and team members chose not to travel in a counterclockwise direction, which would take the rover to the west and south slopes of the plateau. Slopes in that direction are hidden from view and team members chose, following a long, thorough discussion, to have the rover travel clockwise and remain on north-facing slopes rather than risk sending the rover deeper into unknown terrain.

In addition to studying numerous images from Spirit's cameras, rover team members have studied three-dimensional models created with images from the Mars Orbiter Camera on NASA's Mars Globel Surveyor orbiter. The models showed a valley on the southern side of Home Plate, the slopes of which might cause the rover's solar panels to lose power for unknown lengths of time. In addition, images from Spirit's cameras showed a nearby, talus-covered section of slope on the west side of Home Plate, rather than exposed rock layers scientists eventually hope to investigate.

Home Plate has been on the rover's potential itinerary since the early days of the mission, when it stood out in images taken by the Mars Orbiter Camera shortly after Spirit landed on Mars. The rover arrived at Home Plate after traveling 4 miles (6.4 kilometers) across the plains of Gusev Crater, up the slopes of West Spur and Husband Hill, and down again. Scientists are studying the origin of the layering in the outcrop using the Athena science instruments on the rover's arm.

Copyright 2006 by Space Daily, Distributed United Press International