Boeing will attempt to return its problem-plagued capsule from the International Space Station later this week — with empty seats.
Nasa said on Wednesday that everything is on track for the Starliner capsule to undock from the space station on Friday evening.
The fully automated capsule will aim for a touchdown in New Mexico’s White Sands Missile Range six hours later.
Nasa’s two stuck astronauts who flew up on Starliner will remain behind at the orbiting lab. They will return home with SpaceX in February, eight months after launching on what should have been a weeklong test flight.
Thruster trouble and helium leaks kept delaying their return until Nasa decided that it was too risky for them to accompany Starliner back as originally planned.
“It’s been a journey to get here and we’re excited to have Starliner come home,” said Nasa’s commercial crew programme manager Steve Stich.
To make room for them on SpaceX’s next taxi flight, the Dragon capsule will launch with two astronauts instead of the usual four. Two were cut late last week from the six-month expedition, which is due to blast off in late September. Boeing has to free up the parking place for SpaceX’s arrival.
Boeing encountered serious flaws with Starliner long before its June 5 liftoff on the long-delayed astronaut demo.
Starliner’s first test flight went so poorly in 2019 — the capsule never reached the space station because of software errors — that the mission was repeated three years later. More problems surfaced, resulting in even more delays and more than a billion dollars in repairs.
The capsule had suffered multiple thruster failures and propulsion-system helium leaks by the time it pulled up at the space station after launch. Boeing conducted extensive thruster tests in space and on the ground, and contended the capsule could safely bring the astronauts back. But Nasa disagreed, setting the complex ride swap in motion.
The stuck astronauts — retired Navy captains — have lived on the space station before and settled in just fine, according to Nasa officials.
Nasa hired Boeing and SpaceX a decade ago to ferry its astronauts to and from the space station after its shuttles retired. SpaceX accomplished the feat in 2020 and has since launched nine crews for Nasa and four for private customers.