NASA's Orion spacecraft blasts off

NASA's new deep space capsule, Orion, has blasted off atop a massive rocket on its first test flight before carrying humans to an asteroid or Mars in the coming years.

The unmanned spacecraft lit up the skies as it launched from Cape Canaveral on Friday morning atop a Delta IV Heavy rocket.

No astronauts were on board the capsule for the four-and-a-half hour flight that will carry the spacecraft around the Earth twice before splashing down in the Pacific Ocean.

The launch marks the first of a US spacecraft meant to carry people into deep space since the Apollo missions that brought men to the Moon more than four decades ago.

With no American vehicle to send humans to space since the space shuttle was retired in 2011, some at NASA said the Orion launch has re-energised the US space program, long constrained by government belt-tightening and forced to rely on costly rides aboard Russian Soyuz spacecraft to reach the International Space Station in low-Earth orbit.

Potential future missions for Orion, which is designed to fit four people at a time, include a trip to lasso an asteroid and a journey to Mars by the 2030s.