Update on Nov. 16, 2008: The flight team for NASA's Mars Reconnaissance Orbiter has put the spacecraft back into operations. Science instruments have been powered up, and observations of Mars have resumed.
NASA's Mars Reconnaissance Orbiter put itself into a safe standby mode Wed., Nov. 7, after the on-board computer detected that one of the solar panels was moving slower than had been commanded.
The solar panels subsequently have been moving properly, and engineers are working to restore the orbiter to full operations so it can continue scientific observations. At the beginning of this month, the mission completed the first full year of its two-year primary science phase.
Two large solar panels supply Mars Reconnaissance Orbiter's electrical power. Each panel pivots at motorized mechanisms called gimbals where the panel is attached to the spacecraft. The panels are reoriented continuously to keep facing the sun as the spacecraft orbits Mars.
Fault detection software recognized that one gimbal was not maintaining the expected speed. The software properly put the spacecraft into a mode of suspending unnecessary activities and waiting to hear from ground controllers. Preliminary analysis indicates the slower gimbal motion resulted when keepout-zone software, designed to prevent the panels from coming too close to other components, allowed a panel to touch thermal blanketing on the spacecraft. While preparing the orbiter to resume science observations, engineers are also determining how to ensure that the spacecraft correctly manages the solar panels and maintains a safe distance between spacecraft parts.
Mars Reconnaissance Orbiter reached Mars on March 10, 2006, and began its primary science phase after using hundreds of controlled dips into the Martian atmosphere to adjust the size and shape of its orbit. The spacecraft has returned about 30 terabits of science data, including more than 15,000 images from three cameras, more than 3,000 targeted observations by a mineral-mapping spectrometer, and more than 2,200 observations with ground-penetrating radar.