Hubble telescope (file photo)

The U.S. space agency says the main camera on the Hubble Space Telescope is operational again.

NASA says it restarted the Advanced Camera for Surveys Friday, a day after switching the unit to a backup power system.

The camera shut down June 19 after voltage readings from its primary power supply went too high. The orbiting telescope's other instruments continued to operate.

The camera, which was installed by astronauts during a 2002 space shuttle mission, will resume observations on Sunday.

The Hubble telescope orbits 600 kilometers above the Earth. It uses precision optics and other instruments to send back images of the universe far superior to any taken by ground-based telescopes.

NASA has been considering the possibility of sending a repair mission to Hubble to extend its service life.

Some information for this report was provided by AP.