Elon Musk's SpaceX and Nasa launch new astronaut capsule

Elon Musk's SpaceX has successfully  launched a rocket out of the Earth's atmosphere, heralding the rebirth of American manned spaceflight later this year.

The unmanned crew capsule atop a Falcon 9 rocket was launched from Florida bound for the International Space Station at 7.49am GMT on Saturday.

Nasa and SpaceX successfully launched the new astronaut capsule on a week-long trip to the International Space Station and back - a key step towards resuming manned space flights from US soil after an eight-year break.

This time around, the only occupant on board SpaceX's Crew Dragon capsule is a dummy named Ripley, named after the character in Alien played by Sigourney Weaver.

But if the test goes smoothly, Nasa plans to put two astronauts aboard by the end of the year.

Musk, the SpaceX founder, said the launch had left him “emotionally exhausted”.

“That was super stressful - but it worked, so far,” he said.

Before lift off Musk tweeted a photo of the inside of the Crew Dragon capsule with the Ripley mannequin strapped in it.

The new capsule, carrying 400 pounds of supplies and test equipment, is scheduled to reach the ISS by Sunday, with a return to Earth next Friday.

"This is a critically important event in American history," the head of the US space agency, Jim Bridenstine, told reporters, with the rocket and capsule visible behind him on the legendary launch pad where the Apollo missions to the Moon began.

"We're on the precipice of launching American astronauts on American rockets from American soil again for the first time since the retirement of the space shuttles in 2011."

The excitement was palpable at Cape Canaveral, from the space-fan volunteers guiding media on site, to the tourists who came to watch the launch light up the overcast skies.

"It's been a long eight years," the Kennedy Space Center's director Bob Cabana, a former astronaut himself, said as SpaceX employees milled around the rocket.

After the shuttle program was shuttered in July 2011 after a 30-year run, Nasa began outsourcing the logistics of its space missions.

It pays Russia to get its people up to the ISS orbiting research facility at a cost of $82 million a head, for a round trip.

In 2014, the US space agency awarded contracts to SpaceX and Boeing for them to take over this task.

But the program has suffered delays as safety requirements are much more stringent for manned flights than for unmanned missions to deploy satellites.

"We're going to have more access to space at a better cost than at any point in human history," said Bridenstine, adding he was "100 percent confident" that a manned flight would happen by year's end.

What will be learned

Saturday's flight aims to test the vessel's reliability and safety in real-life conditions.

The dummy that will ride in the capsule - which SpaceX's Hans Koenigsmann prefers to call a "smartie" - has been nicknamed Ripley in honor of the character played by Sigourney Weaver in the "Alien" movies.

It will be fitted with monitors to test the forces that future astronauts will be subjected to on takeoff and when they return to the Earth's atmosphere and then splash down in the Atlantic, slowed down by giant parachutes.

"We're going to learn a ton from this mission," said Kathy Lueders, the manager of Nasa's Commercial Crew program.

For SpaceX, which Musk founded in 2002, sending an astronaut into orbit would be a culmination of years of hard work and high-risk investment.

"Every mission is important, but this is even more important, said Koenigsmann, the firm's vice-president for build and flight reliability.

"Early on, our goal was human spaceflight," he said. "Human spaceflight is a core value of business of SpaceX."

In less than a decade, SpaceX has become a key partner for Nasa, in addition to dominating the market for private satellite launches.

Its Falcon 9 rockets have resupplied the space station 15 times in seven years, even though one of them blew up in 2015.