The Boeing-produced Starliner left the International Space Station (ISS) on Friday, landing back on Earth in the early hours of Saturday, without the astronauts who rode up on the spacecraft.

The Starliner autonomously undocked from the space station at 6:04 p.m. Eastern Time (2204 GMT).

Shortly after undocking, Starliner performed a powerful "breakout burn" to quickly move away from the station to avoid a collision.

This maneuver would have been unnecessary if Starliner had a crew on board, as they would be able to manually control the ship.

The empty spacecraft landed gently at White Sands Space Harbor in New Mexico at 0401 GMT.

What happened to the spacecraft?

After years of delays, Starliner blasted off in June for what was supposed to be a week-long test mission before it could finally be certified to ferry crews to and from the ISS.

But unexpected engine failures and helium leaks on the way up derailed those plans. NASA ultimately decided it would be safer to bring astronauts Butch Wilmore and Suni Williams back on a rival craft, the SpaceX Crew Dragon.

Two NASA astronauts have been bumped off that flight so that Wilmore and Williams can return to earth.

Their stay was to last only a week but now they have to wait until February 2025to return.

As experienced astronauts and retired Navy captains, Wilmore and Williams expected hurdles on the test flight. They've been busy in space, helping with repairs and experiments. The two are now full-time station crew members, along with the seven others on board.

The Starliner will now be analyzed for flaws and improved. Steps will be taken to prevent helium leaks and overheating of the propulsion system. 

What is the Starliner?

The Starliner, built by Boeing, is a partially reusable spacecraft consisting of a crew capsule about 3 meters high and a service module.

Unlike the Crew Dragon vehicle built by Elon Musk's SpaceX, the Starliner lands on land instead of water.

The landing feature is similar to that of NASA's former workhorse, the Space Shuttle, the last of which was retired in 2011.

A smooth Starliner's flight is critical not only to salvage some pride but also to Boeing's prospects for future certification.

NASA officials have stated that they will continue to work with Boeing as well as SpaceX.
 

dh/sms (AFP, AP, dpa)