Elon Musk’s SpaceX has launched a rocket out of the Earth’s atmosphere, in a major step towards reviving America’s human spaceflight programme.
The unmanned crew capsule atop a Falcon 9 rocket was fired from Florida bound for the International Space Station at 7.49am GMT.
The key test flight is aiming to prove to NASA that astronauts will be safe on future flights.
Before lift off, billionaire Musk tweeted a photo of the inside of the Crew Dragon capsule with a mannequin nicknamed Ripley strapped in it.
SpaceX said the spacesuit for Ripley, apparently a reference to the protagonist in the sci-fi movie Alien played by Sigourney Weaver, has been embedded with sensors around its head, neck, and spine to monitor how a flight would feel for a human astronaut.
The International Space Station’s three-member crew is expected to greet the capsule, carrying 400 pounds of supplies and test equipment, on Sunday, NASA said.
During its five-day stay, US astronaut Anne McClain and Canadian astronaut David Saint-Jacques will run tests and inspect Crew Dragon’s cabin.
Among the 5,000 spectators watching the launch in Florida were two NASA astronauts, Doug Hurley and Bob Behnken, who will strap in as early as July for the second demo flight.
It has been eight years since Mr Hurley and three other astronauts flew the last space shuttle mission, and human launches from Florida ceased.
NASA awarded SpaceX and Boeing Co $ 6.8bn (£5.2bn) to build competing rocket and capsule systems to launch astronauts into orbit from American soil for the first time since the US Space Shuttle was retired from service in 2011.
The Boeing and SpaceX launch systems are aimed at ending US reliance on Russian rockets for rides to the $ 100bn (£75.7bn) orbital research laboratory, which flies about 250 miles (402 km) above Earth, at about $ 80m (£60.6m) per ticket.
While Saturday’s SpaceX test mission is a crucial step in the long-delayed project, there are questions about whether NASA can achieve its 2019 flight goal.
It has been reported that SpaceX and Boeing both must address significant design and safety concerns before they can fly humans.