Nasa astronauts Bob Behnken and Doug Hurley are aboard the International Space Station.
The pair floated into the station from their SpaceX Dragon capsule at 5.22 am NZT,, 20 minutes after they opened the hatch. They were greeted by fellow Nasa astronaut Chris Cassidy, who has been on the station since April, and two Russian cosmonauts.
Their arrival completed the last major milestone of the launch that began Saturday when the SpaceX Falcon 9 lifted off from pad 39A at the Kennedy Space Centre.
The spacecraft, now named Endeavour, docked with the station at 2.16 am (NZT) Sunday, and the crews then worked to equalize the pressure between the spacecraft and the station before opening the hatch.
Behnken and Hurley will remain onboard the station for between one and four months.
In addition to Cassidy, two Russian cosmonauts, Anatoly Ivanishin and Ivan Vagner, are aboard the station.
The docking was a delicate and dangerous part of the mission. The spacecraft chased down the space station, travelling in orbit at over 28,000 kilometres an hour, but then approached very slowly in a series of carefully choreographed manoeuvres.
The mission went smoothly, ground officials said, following a picture-perfect launch some 19 hours earlier from the Kennedy Space Centre.
Shortly after docking, Hurley said, “it’s been a real honour to be just a small part of this nine-year endeavour since the last time a United States space ship docked with the International Space Station.”
In Houston’s mission control, flight director Zeb Scoville congratulated the crew.
“Bravo on a magnificent moment in spaceflight history,” he said, “and on the start of a new journey that has changed the face of space travel in this new era of space transportation.”
The flight is the first launch of Nasa astronauts since the Space Shuttle retired in 2011, and the first of a private company of humans to orbit.
Behnken and Hurley said during a live broadcast on Monday (NZT) that they have had a smooth ride so far, got a decent night’s sleep and awoke this morning to Black Sabbath’s “Planet Caravan,” continuing a Nasa tradition of waking astronauts to music.
En route to the space station, the Dragon spacecraft performed a series of “burns,” or engine thrusts that raised its orbit to eventually match that of the station. Shortly before 1am NZT the spacecraft was moving into position about 400 metres below the station.
The Dragon spacecraft flies autonomously, but the astronauts can take over the controls at any time, and seem to be enjoying flying a modern spacecraft.
During a broadcast from the capsule, Hurley noted that they were the first astronauts to control a spacecraft using a touchscreen.
“So we got that going for us,” he said.