The Hubble Space Telescope has broken down, and scientists aren't sure why.

The telescope, which has revolutionized space science, went down on Monday and is still not working despite efforts by scientists to trace the problem.

The camera on the Hubble Space Telescope has stopped working.
(NASA/Associated Press)

Ed Campion, a NASA spokesman at the Goddard Space Flight Center outside Washington, D.C., told the Associated Press Saturday that he was hopeful the problem on the space-based telescope could be fixed from the ground.

NASA experts suspect a faulty transistor or perhaps a cosmic event has wiped out part of the camera's memory. The transistor can probably be replaced by a back-up unit, while the camera's memory can be reloaded.

"Both possibilities are things that can be resolved here on the ground," Campion said.

The Advanced Camera for Surveys, an integral part of the Hubble, is a third-generation instrument that was installed by a space shuttle crew in 2002. It has three separate electronic cameras and a collection of filters and light dispersers that are used to photograph distant planets and stars.

The Hubble has transformed space exploration because it sits high above the atmosphere, and far above the dust, moisture, pollution and light effects that plague Earth-based telescopes.