The SpaceX Crew Dragon spacecraft that carried two Nasa astronauts to the International Space Station (ISS) late in May is set to depart the orbiting laboratory on August 1 and reach Earth on August 2, marking the end of the first crewed mission for the Elon Musk-led company.

Making the announcement in a tweet, Nasa Administrator Jim Bridenstine said that "weather will drive the actual date".

The Crew Dragon spacecraft carrying Nasa astronauts Robert Behnken and Douglas Hurley launched aboard a SpaceX Falcon 9 rocket on May 30, becoming the first crewed launch from the US after the government retired the space shuttle program in 2011.

This is also the first-ever crewed mission for SpaceX.

"We're targeting an Aug. 1 departure of @SpaceX's Dragon Endeavour spacecraft from the @Space_Station to bring @AstroBehnken and @Astro_Doug home after their historic #LaunchAmerica mission. Splashdown is targeted for Aug. 2. Weather will drive the actual date. Stay tuned," Bridenstine said in the tweet.

Known as Nasa's SpaceX Demo-2, the mission is an end-to-end test flight to validate the SpaceX crew transportation system, including launch, in-orbit, docking and landing operations.

The Demo-2 mission is the final major test before NASA's Commercial Crew Programme certifies Crew Dragon for operational, long-duration missions to the space station..