Video report by ITV News Correspondent Geraint Vincent
NASA has launched astronauts into space from United States soil for the first time in nine years.
Astronauts Doug Hurley and Bob Behnken successfully launched on Saturday on board SpaceX's Dragon capsule and Falcon 9 rocket - built by billionaire entrepreneur Elon Musk’s firm.
The Demo-2 mission launched at 20:22 BST (15:22 EDT, 19:22 GMT) from the Kennedy Space Centre in Florida.
The team were set for a rare ride on Wednesday, but bad weather postponed their trip.
It was touch and go ahead of the launch as to whether things would go ahead, with forecasters warning of poor conditions.
Speaking ahead of the launch, NASA astronaut Jim Bridenstine said thunderstorms were expected and that there was a 50-50 chance of lift-off.
All went to plan, however, with Space X confirming the first stage of entry burn was complete within ten minutes of the launch.
The second stage - propelling the crew into orbit - also went as planned sending astronauts Doug Hurley and Bob Behnken on their way to the ISS.
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President Donald Trump was there to witness the launch, tweeting in advance of the successful take off: "Hopefully a great, successful and safe ROCKET LAUNCH. Lifting off soon!?!?"
Mr Trump later said: "I am thrilled to announce that the SpaceX Dragon capsule has successfully reached low-Earth orbit and that our astronauts are safe and sound.
"With this action the decades of lost and little action are officially over. A new age of American ambition has now begun."
He added: "Today's launch makes clear the commercial space industry is the future."
NASA hope Demo-2 will prove SpaceX's ability to ferry astronauts to the space station and back safely.
The demonstration mission is the final major step required by SpaceX's astronaut carrier, the Crew Dragon, to get certified by Nasa's Commercial Crew Programme for more long-term manned missions to space.
The Demo-2 mission is expected to last anything between one and four months. But NASA said the duration of this mission would be determined by when the next commercial crew will be able to travel to the space station.
The spacecraft will be capable of staying in orbit for at least 210 days.
When it is time to return, the Crew Dragon will autonomously undock with Mr Behnken and Mr Hurley on board and depart the space station.
Moments after the Dragon capsule made it into orbit the crew were given a message from the team on the ground.
The Falcon 9's chief engineer said: "On behalf of the entire launch team, thanks for flying with Falcon 9 today. We hope you enjoyed the ride and wish you a great mission."
One of the crew replied: "Congratulations to you and the F9 team for the first human ride for Falcon 9 and it was incredible. Appreciate all the hard work and thanks for the great ride to space."
The launch puts SpaceX into the history books as the first private company to send humans into orbit - marking a new era for commercial space travel.
Tim Peake tweeted his congratulations writing on Twitter: "I loved watching the acceleration during the final minutes of launch - it's a crazy, crazy feeling being hurled up to 27000kmh!"