Space missions to Hubble telescope end

Nasa is cancelling all space-shuttle servicing missions to the Hubble space telescope, a decision that in effect will cause the powerful observatory to slowly degrade and eventually become useless, say officials.

John Grunsfeld, Nasa's chief scientist, said the US space agency's administrator, Sean O'Keefe, decided to cancel the fifth space-shuttle service mission to the Hubble when it became clear there was not enough time to conduct it before the shuttle was retired.

The servicing mission was considered essential to enable the orbiting telescope to continue to operate.

Grunsfeld said the decision was influenced by President George W. Bush's new space initiative, which calls for Nasa to start developing the spacecraft and equipment for voyages to the moon and later to Mars. The President's plan also called for the space shuttle to be retired by 2010.