NASA to Revive Cassini Spacecraft at Saturn

NASA is preparing to revive the dormant Cassini spacecraft in orbit around Saturn, which ceased science operations three weeks ago due to a computer glitch.

Cassini mission controllers plan to reawaken the Saturn probe tomorrow (Nov. 24). The spacecraft has been operating in a protective standby mode ? called "safe mode" ? since Nov. 2 because of an ill-timed flip of a data bit in Cassini's command and data system computer.

"The bit flip happened in exactly the wrong location ?  almost anyplace else would have merely resulted in a rejected command ? but the spacecraft responded exactly as programmed," Cassini program manager Bob Mitchell, of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., said in an update this month. "Cassini is in excellent shape, and we are looking forward to the next seven years of this mission." [Cassini's Greatest Hits: Photos of Saturn]

This latest computer hiccup marked the sixth time since Cassini's launch in 1997 that the spacecraft went into safe mode. During that time, the probe beamed engineering and spacecraft health data to its mission operations center at JPL, but could not perform science observations.

The glitch forced mission planners to skip planned observations of Saturn's largest moon Titan during a Nov. 11 flyby of the cloud-covered satellite.

Over the last week, Cassini engineers commanded the probe to reset its sick computer to fix the bit flip problem. Science instruments were also slowly reactivated and mission managers hope to recover data lost during the initial malfunction, JPL officials said.

"Playback from the computer's memory is enabling engineers to extract science data collected before the spacecraft entered safe mode," JPL officials said.

The Cassini spacecraft arrived in 2004 to study Saturn and its rings, and to deliver the European-built Huygens probe to land on Titan. Cassini completed its primary mission in 2008 and is now in its second extended phase that extends through May 2017.

The mission is a collaborative effort between NASA, the European Space Agency and the Italian Space Agency.

• Gallery: The Rings and Moons of Saturn
• Cassini's Greatest Hits: Photos of Saturn
• 30-Year Saturn Odyssey: From NASA's Voyagers to Cassini Today