The flight will be the last for Discovery, the first of three shuttles NASA plans to retire this year [Reuters]

Space shuttle discovery, NASA's most heavily travelled spacecraft, has blasted off from Florida on its final mission.

The shuttle blasted off on Thursday carrying six astronauts and a load of supplies, spare parts and a robot for the International Space Station.

The shuttle lifted off at 4:53 p.m. EST (2153 GMT) from the Kennedy Space Center, riding a flame-tipped pillar of smoke across the Atlantic Ocean as it soared toward space.

The launch was delayed by three minutes when a range safety computer shut down before the planned 4:50pm EST (2150 GMT) lift-off. The problem was resolved with seconds to spare, clearing Discovery for launch.

The launch was the 133rd for the 30-year-old shuttle programme, with up to two flights remaining before the three-ship fleet is retired later this year.

Discovery made 39 of those flights, including both return-to-flight missions following the fatal Challenger and Columbia accidents.

"I think what will be most difficult will be on landing day when we know that that's the end of her mission, completely," said launch director Mike Leinbach.

The shuttle carries a storage room, a spare parts platform and a prototype humanoid robot for the space station, a $100bn project of 16 nations nearing completion after more than a decade of construction 220 miles (354 km) above the Earth.

The shuttles are being retired due to high operational costs and to free up money to develop new vehicles capable of traveling beyond the space station's orbit.

Source: Agencies