In short:
Two US astronauts who have been stuck on the International Space Station for weeks say they are confident the Starliner capsule that flew them up can bring them down safely.
Their return has been repeatedly pushed back as engineering teams on Earth continue to run tests to understand malfunctions that came to light on the flight up.
What's next?
The earliest the astronauts might return is the end of July, NASA said, with mid-August being another deadline due to a SpaceX delivery of a fresh crew to the station.
Two US astronauts who should have returned to Earth weeks ago say they are confident that the problem-plagued Boeing Starliner spacecraft they rode up on can bring them back safely, despite significant uncertainties remaining.
"I have a real good feeling in my heart that this spacecraft will bring us home, no problem," NASA astronaut Sunita "Suni" Williams said on Wednesday during the test crew's first news conference since docking to the International Space Station (ISS) more than a month ago.
Captain Williams and mission commander Barry "Butch" Wilmore blasted off on June 5 on what was Starliner's first crewed mission, intended as the final demonstration for Boeing to obtain routine flight certification from NASA.
The crew's stay was meant to last roughly a week, but the return was pushed back because of thruster malfunctions and helium leaks that came to light during the journey.
Loading...
Engineering teams back on Earth need to run tests to better understand the issues and potentially modify how Starliner will fly down.
No return date has been set so far with the end of July the earliest option, NASA officials said.
'Failure is not an option'
In the pair's first news conference from orbit, Commander Wilmore said he remained "absolutely confident" in the Starliner spaceship and team.
"That mantra you've heard, 'failure is not an option,' that's why we are staying here now," he said.
"We trust that the tests that we're doing are the ones we need to do to get the right answers, to give us the data that we need to come back."
The pair said they're not complaining about getting extra time in orbit, and are enjoying helping the station crew.
Both have previously spent stints at the orbiting lab, which is also home to a seven-member resident crew.
Return postponed again
NASA's commercial crew program director Steve Stich said the earliest the Starliner astronauts might return is the end of July.
The goal is to get them back before Boeing's competitor SpaceX delivers a fresh crew in mid-August, but that could change, he noted.
The return, which was originally scheduled for June 14, has already been postponed twice.
In 2014, SpaceX and Boeing were awarded multi-billion-dollar contracts by NASA to develop crewed spaceships to shuttle crew to and from the space station.
SpaceX's first taxi flight with astronauts was in 2020 and it has flown dozens of people on its Crew Dragon capsule since.
Boeing's first crew flight, on the other hand, was repeatedly delayed because of software and other issues.
Mr Stich insisted that NASA wasn't considering bringing their pilots back on the SpaceX capsule, in what would amount to a major humiliation for Boeing.
"The prime option today is to return Butch and Suni on Starliner," Mr Stich said.
However, he conceded that a return flight on a SpaceX spaceship can't be ruled out.
Boeing executive Mark Nappi stressed that in an emergency, Starliner and its crew could return right now.
While the company does not believe the thrusters are damaged, Mr Nappi said they want to "fill in the blanks and run this test to assure ourselves of that".
Plagued program adds to Boeing's problems
Boeing's Starliner program has a long history of issues, including software glitches, design problems and subcontractor disputes.
Its first crewed launch was delayed for two years before Captain Williams and Commander Wilmore finally lifted off into space.
At one point, technical difficulties caused a postponement just 24 hours before launch.
In 2019, the first attempt to send an uncrewed Starliner to the ISS failed due to software and engineering glitches, before a successful second attempt in 2022.
The company has already spent $US1.5 billion ($2.2 billion) in cost overruns, on top of its US$4.5 billion NASA development contract.
Starliner's problems add to Boeing's ongoing safety and public relations struggles on its commercial aircraft side.
The aerospace giant recently agreed to plead guilty to a criminal fraud conspiracy charge in an investigation linked to two fatal crashes of its 737 MAX commercial aircraft. The company will pay a criminal fine of $US243.6 million.
Several other incidents involving Boeing's planes, including an unused emergency exit door blowing off mid-flight, have taken their toll on the company's reputation.
ABC/wires
Posted, updated
