Nasa astronauts speak out amid claims they are 'stuck in space'

Their return has been delayed repeatedly after the Boeing Starliner suffered multiple helium leaks and thruster issues

Nasa astronauts Suni Williams, left, and Butch Wilmore speak during an online media briefing from the International Space Station on July 10. Nasa

Two Nasa astronauts aboard the International Space Station have said that they trust the Boeing Starliner spacecraft to bring them home safely despite its multiple technical issues.

Suni Williams and Butch Wilmore, speaking from the station during an online media briefing on Wednesday, arrived on June 6 for what was initially planned as a week-long test flight mission.

The craft has suffered multiple helium leaks and thruster issues since arriving there, causing the crew's return to be delayed repeatedly, with no firm unlocking date set yet by Boeing and Nasa.

“I feel confident that if we had to, if there was a problem with the International Space Station, we can get in our spacecraft, we can undock, talk to our team and figure out the best way to come home,” said Ms Williams, an experienced astronaut who logged more than 322 days in space before this mission.

“We've practised a lot, so I have a real good feeling in my heart that this spacecraft will bring us home.”

Boeing has insisted that they are delaying the return so that they can get more testing done before the craft can undock from the station, as the service module will be discarded upon re-entry into Earth's atmosphere.

The company and Nasa are now carrying out ground tests in New Mexico, in which they are replicating thruster issues that the craft experienced during its flight in a vacuum chamber to learn more about the problem.

Starliner has to depart before August so that it frees up the docking part for the next set of astronauts, Nasa/SpaceX Crew-9, to arrive at the station aboard a SpaceX Dragon capsule.

“A few days before that launch opportunity we would need to get Butch and Suni home on Starliner,” Steve Stich, commercial crew programme manager at Nasa, said in a media briefing last night.

“We’re really working to try to follow the data and see when is the earliest we could target for undock and landing. I think some of the data suggests, optimistically, it’s by the end of July.”

He said they were also considering the option of making Crew-8, who are currently serving a mission aboard the station, depart earlier than planned so that a docking port is available.

Boeing has a $4.2 billion contract under Nasa's Commercial Crew Programme to develop a craft that can help safely launch and bring back astronauts for the agency.

Starliner has been in development for a decade and has faced multiple technical issues over the years.

Meanwhile, SpaceX has launched eight crews for Nasa so far using its Falcon 9 rocket and Dragon capsule.