The main camera on the Hubble Space Telescope, which has revolutionised astronomy with its stunning pictures of the universe, has stopped working, an instrument specialist who works with the camera said on Saturday.
The Advanced Camera for Surveys, a third-generation instrument installed by a space shuttle crew in 2002, went off-line on Monday, and engineers are still trying to figure out what happened and how to repair it.
"It's still off line today," Max Mutchler, an instruments specialist at the Space Telescope Science Institute in Baltimore, said on Saturday.
Engineers are hopeful the problem can be fixed, said Ed Campion, a NASA spokesman at Goddard Space Flight Centre outside Baltimore, which is responsible for managing the Hubble.
A bad transistor could be causing the trouble, Campion said. If so, a backup could be used. Another suspicion is that some of the camera's memory was disturbed by a cosmic event. That could be fixed by reloading the memory.
"Both possibilities are things that can be resolved here on the ground," Campion said.
The camera sent messages on Monday indicating power supply voltages were above their upper limits and causing it to stop working.