Nasa astronauts Doug Hurley and Bob Behnken landed on the International Space Station (ISS), over two hours after docking with the orbiting laboratory. They had to run pressure and leak tests before exiting the Crew Dragon capsule.
They met American astronaut Chris Cassidy and Russian space station residents Anatoli Ivanishin and Ivan Vagner, as they left their spacecraft.
Both are currently official affiliates of the Expedition 63 crew.
Speaking to the men from mission control in Houston, Texas, Nasa administrator Jim Bridenstine said: “The whole world saw this mission and we are so, so proud of everything you’ve done for our country and, in fact, to inspire the world.”
Mr Hurley and Mr Behnken’s 19-hour itinerary on SpaceX’s Dragon capsule on top of the Falcon 9 rocket started in Cape Canaveral in Florida on Saturday evening.
Despite only being 300 miles above the planet, the space station took almost a day to reach.
A number of manoeuvres had to be performed to raise its orbit to get close enough to hook up to the space station.
The assignment, dubbed Demo-2, is the first mission Nasa where has launched astronauts from the US in nine years.
SpaceX also became the first private firm to launch humans into orbit in a historic event.
“Doug and I will be able to take some burden off Chris and his crew mates Ivan and Anatoli, so that we can keep the space station operating at a peak possibility.
“So we are looking forward to contributing any way that we can and, like I said, trying to keep (the) space station as productive as possible.”
The mission is expected to last anything between one and four months.
Speaking of their sleeping patterns, Mr Behnken said: “We did get probably a good seven hours or so of opportunity for sleep and I did succeed at sleep and Doug did as well.”The first night is always a bit of a challenge but the Dragon was a sleek vehicle and we had good airflow. So we had an excellent evening.”
He added that he was “excited to be back in low-Earth orbit again.”
Mr Behnken said while they are on the space station, they hope to put the Dragon capsule, which they called Endeavour, through its paces and aiding other members of the crew in different other exercises.
He added: “Endeavour is going to get a lot of checkout over the next week or two here and hopefully we will be able to declare her operational.
“Doug and I will be able to take some burden of Chris and his crew mates Ivan and Anatoli so that we can keep the space station operating at a peak possibility.
“So we are looking forward to contributing any way that we can and like I said trying to keep (the) space station as productive as possible.”