US space agency NASA said Tuesday its scientists are working to restore the long-lived Mars Reconnaissance Orbiter to full operations after the spacecraft suffered a computer glitch Sunday.

The Mars orbiter put itself into a precautionary safe standby mode on March 9 after an unscheduled swap from one main computer to another, NASA said.

"The spacecraft is healthy, in communication and fully powered, " Mars Reconnaissance Orbiter Project Manager Dan Johnston of NASA 's Jet Propulsion Laboratory said in a statement.

"We have stepped up the communication data rate, and we plan to have the spacecraft back to full operations within a few days," Johnston said.

So far, the spacecraft's science observations and its relaying of communications from NASA's two active Mars rovers have been suspended, the agency said.

The rovers continue to use NASA's Mars Odyssey orbiter as a communications relay, it noted.

According to NASA, the Mars Reconnaissance Orbiter has experienced unplanned computer swaps triggering safe-mode entry four times previously, most recently in November 2011.

The root cause of the previous events has not been determined, it added.

The spacecraft has also experienced safe-mode entries that have not involved computer swaps.

The Mars Reconnaissance Orbiter entered orbit around Mars eight years ago. The primary mission is scheduled for only two years, and the spacecraft is now on its third extension that began in 2012.