Astronauts on the space shuttle Endeavour have begun their 11-day mission to map the Earth.

The first swath in the 24-hour-a-day mission covered southern Asia and the northern Pacific Ocean.

Six crew members divided into two teams will monitor the mapping, covering more than 70% of the Earth's land surface.

After manoeuvring a 197ft radar mast out of the cargo bay, five-and-a-half hours after Friday's lift-off at 1743GMT, Endeavour's crew turned on the mapping system and began taking a close look at the Earth from 145 miles up.

Shuttle pilot Dominic Gorie said: "So far everything has gone about as perfectly as we could have imagined.

"We woke up to a perfect vehicle and a perfect radar system. We started mapping early, and so far everything has gone just fine.''

The first countdown on 31 January failed due to a combination of bad weather and technical problems. The original launch date was supposed to be in September 1999.

The computer unit that malfunctioned in the final minutes of the first countdown had been replaced and the extensive attention to the condition of the whole shuttle fleet in recent months meant that Endeavour was in "tiptop shape", according to shuttle programme manager Ron Dittemore.

The mission is largely sponsored by the US National Imagery and Mapping Agency, which supplies top-secret satellite and reconnaissance images to US defence and intelligence agencies.

Most of the best-quality maps generated by this mission will remain classified but lower resolution maps are to be made available to the public for use by scientists, civil engineers and commercial companies.