The SpaceX Crew Dragon spacecraft carrying NASA astronauts Robert Behnken and Douglas Hurley was on its way to the orbiting laboratory in the space and had safely reached orbit, NASA said in a statement.

It is the first time that astronauts have been sent into space from the US soil since 2011.

It is also the first time that US astronauts have been sent into space by a private company, signalling an end to the US dependence on the Russian space technology.

The Crew Dragon spacecraft lifted off from NASA's Kennedy Space Center in Florida, the same site used for the first moon landing in 1969, reports the BBC.

The journey would take approximately 19 hours and astronauts Hurley and Behnken should reach the space station at around 10.30 ET (eastern time) on Sunday, according to NASA.

After successfully docking, Behnken and Hurley will be welcomed aboard station and will become members of the Expedition 63 crew. They will perform tests on Crew Dragon in addition to conducting research and other tasks with the space station crew.

Earlier, NASA and SpaceX postponed historic launch of two astronauts to space from NASA's Kennedy Space Center in Florida on Wednesday due to bad weather.