NASA's Mars Reconnaissance Orbiter is in safe mode, a precautionary standby status, and in communications with Earth after unexpectedly switching to its backup computer on Thurs. Aug. 6.

Engineers are working to determine the cause of the spontaneous swap from the orbiter's "A" side computer and subsystems to the redundant "B" side. They have successfully increased the communication rate from the orbiter, but some engineering data about what was occurring just before the side swap may never be available. The team expects it will be at least several days until normal science operations resume.

The event has some similarities with, but also differences from, two earlier instances of the Mars Reconnaissance Orbiter spontaneously swapping sides.

Jim Erickson, Mars Reconnaissance Orbiter project manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif., said, "The spacecraft is safe, with good temperatures and battery charge and with solar panels properly facing the sun. The flight team is cautiously taking steps to bring it back to normal operations."

The Mars Reconnaissance Orbiter has been studying Mars with an advanced set of instruments since 2006. It has returned more data about the planet than all other past and current missions to Mars combined.