CAPE CANAVERAL - NASA is on target for its launch of the space shuttle Atlantis on its final mission to service the Hubble telescope, the US space agency said on Sunday.

'Atlantis is ready to fly,' said test director Charlie Blackwell-Thompson, adding that the countdown to launch was proceeding on schedule, with liftoff expected on Monday at 2.01pm (1801 GMT, 2.01am Singapore time).

Weather forecasters said there was a 90 per cent chance of favourable conditions for the launch from Kennedy Space Center in Cape Canaveral, Florida.

The 11-day shuttle mission aims to provide the fifth and final maintenance operation to the Hubble before the shuttle fleet is retired, and if successful Nasa has said the mission would extend the star-gazer's life by at least five years.

Hubble's servicing will entail five space walks, each lasting up to seven hours. Crew members plan to replace the telescope's six gyroscopes and batteries and upgrade its optical instruments.

Launched in 1990, Hubble has long been considered the greatest tool in the history of astronomy.

Using powerful instruments to peer into deep space, it has provided profound insights into the origins and evolution of the universe. -- AFP