SpaceX’s sleek, new crew capsule arrived at the International Space Station (ISS) on March 3, acing its second milestone in just over a day. Only an instrumented dummy was aboard the Crew Dragon capsule launched on March 2 on its first test flight. But that quickly changed once the hatch swung open and the space station astronauts floated inside.

SpaceX employees at company headquarters in Hawthorne, California, cheered and applauded as Crew Dragon pulled up and docked at the orbiting lab, nearly 400 km above the Pacific, north of New Zealand. This beefed-up, redesigned Dragon is the first American-made, designed-for-crew spacecraft to pull up to the station in eight years.

The next one coming up will have its own two-man crew. The space station’s three astronauts had front-row seats as the white 8-metre-long capsule neatly docked. Two hours later, the station crew entered to take air samples, wear oxygen masks and hoods until getting the all-clear. Dragon will remain at the space station until March 8, when it undocks and aims for a splashdown in the Atlantic, a couple hundred miles off the Florida coast.

If the six-day demo goes well, SpaceX could launch two astronauts this summer under NASA’s commercial crew programme. Both astronauts, Doug Hurley and Bob Behnken, were at SpaceX Mission Control in California, watching all the action. SpaceX aims to launch Behnken and Hurley as early as July.

The capsule’s lone passenger for launch - a mannequin wearing a white SpaceX space suit - remained strapped into its seat as the station’s US, Canadian and Russian crew removed supplies and photographed the spotless white interior. The test dummy or Smarty as SpaceX likes to call it is named Ripley after the lead character in the science-fiction Alien films. Like Ripley, the capsule is rigged with sensors to measure noise, vibration and stresses, and to monitor the life-support, propulsion and other critical systems throughout the flight.

While the private SpaceX has sent plenty of its Dragon capsules filled with cargo to the space station for NASA, Crew Dragon is a different beast. It docked on its own, instead of relying on the station’s robot arm for berthing. The capsule’s nose cap was wide open like a dragon’s mouth, to expose the docking mechanism. For operational missions, Crew Dragon will be able to launch as many as four crew members and carry more than 90 kg of cargo, enabling the expansion of the crew members, increasing the time dedicated to research in the unique microgravity environment, and returning more science back to Earth.

Next up should be Boeing, NASA’s other commercial crew provider. Boeing is looking to launch its Starliner capsule without a crew as early as April and with a crew possibly in August. NASA is paying the two private companies $8 billion to build and operate the capsules for ferrying astronauts to and from the space station. Astronauts have been stuck riding Russian rockets ever since NASA’s space shuttle programme ended in 2011. Russian Soyuz seats go for up to $82 million apiece.