SpaceX delivered two astronauts to the International Space Station for NASA on Sunday, following up a historic liftoff with an equally smooth docking in yet another first for Elon Musk’s company.

With test pilots Doug Hurley and Bob Behnken poised to take over manual control if necessary, the SpaceX Dragon capsule pulled up to the station and docked automatically, no assistance needed. The hatches swung open a few hours later, and the two Dragon riders floated into the orbiting lab and embraced the three station residents.

Unlike the SpaceX and NASA flight control rooms, where everyone was spaced well apart, there was no social distancing or masks needed in orbit since the new arrivals had been in quarantine for many weeks.

Elon Musk’s “biggest concern” is reentry — the final stage of SpaceX’s biggest mission for NASA, when its astronauts must hurtle back to Earth.

Russia has lost its long-held monopoly as the only country able to ferry astronauts to the International Space Station following the flawless manned launch by US company SpaceX.

The Russian space agency congratulated the United States and Elon Musk’s SpaceX on the first crewed flight ever by a private company, but experts said the launch should be a wakeup call for Roscosmos.

“The success of the mission will provide us with additional opportunities that will benefit the whole international programme,” cosmonaut Sergei Krikalev, Roscosmos executive director for crewed space programmes, said in a brief video address.

NASA has estimated a 1-in-276 chance that the astronauts on the SpaceX rocket could die during the company’s first crewed mission.

In the beginning, everyone was skeptical. But Elon Musk’s SpaceX defied expectations — and on Wednesday hopes to make history by ferrying two NASA astronauts into space, the first crewed flight from US soil in nine long years.