Two NASA spacecraft have stopped normal operations by entering "safe mode".
NASA's Compton Gamma Ray Observatory (GRO) has shut down its observations and conducted an autonomous sun-pointing exercise. The shutdown is possibly related to the loss of one of the craft's three gyros.
Scientists believe that observation work can be resumed shortly, with the telescope operating on two, or one, gyros.
GRO was deployed from the Space Shuttle Atlantis in 1991 as part of NASA's Great Observatory programme.
Meanwhile, NASA suspects that the month-long safe-mode configuration of the $152 million Deep Space 1 new Millennium programme spacecraft may have been caused by a short circuit.
Previous glitches on the spacecraft have been corrected by its Remote Agent artificial intelligence system.
The short circuit occurred on 1 November when a plasma instrument was powered up.
The short may have damaged the electrical circuits of the spacecraft's star tracker, which prevented the correction of a fault on 11 November.
Source: Flight International