The main camera on the Hubble space telescope has shut down after an electrical failure, Nasa has said.
Astronomers are calling the malfunction of the Advanced Camera for Surveys a "great loss" as it has taken the clearest pictures yet of the universe.
Scientists for the US space agency said only one-third of the camera's capabilities are likely to be restored.
A new camera is to be installed during a planned space shuttle mission to the Hubble telescope in 2008.
The camera has been the most in-demand instrument of the Hubble telescope since it was installed in 2002.
The Advanced Camera for Surveys actually consists of three sub-cameras that detect and filter light from the ultraviolet to the near infrared.
Astronomers can continue to use the Hubble's other instruments but the loss of its primary camera is being mourned by the scientific community.
"Science will continue, but it's a great loss, no doubt," said Mario Livio at the Space Telescope Science Institute.
"It's a great loss because this was a fantastic camera that just produced incredible science."
The Hubble space telescope has been orbiting the earth since 1990, permitting astronomers to make observations of the universe without the distorting effect of the earth's atmosphere.
http://news.bbc.co.uk/2/hi/science/nature/6312091.stm