Nasa has again delayed a decision about how to bring home two US astronauts stuck in space on the troubled Boeing Starliner mission.
The US space agency said in a press conference on Wednesday that it will make a call by the end of August.
Officials also said that the astronauts’ space suits are unsuitable to wear on the alternative spacecrafts that could be used if Starliner is deemed unsafe.
Nasa also said the two astronauts were “doing great” and went to space prepared for a risky mission.
Suni Williams and Butch Wilmor travelled to the International Space Station (ISS) on 5 June, expecting to return after eight days.
But the Starliner craft ran into trouble when five of the spacecraft’s thrusters, which help it manoeuvre, cut out on the approach to the ISS. Helium gas, which pushes fuel into the propulsion system, also leaked.
The problems mean Ms Williams and Mr Wilmore have to remain on the ISS while engineers carry out a high-level technical review.
One alternative way for them to return home is using a SpaceX craft leaving in autumn. More likely, they also could travel on a SpaceX flight early next year.
The latter would turn an eight-day mission into eight-month trip.
It is not a simple task to change how the astronauts travel back to Earth.
Officials said on Wednesday that the astronauts’ space suits are not interchangeable. If they returned on the earlier SpaceX flight, they would travel without Space X-specific suits, which could pose additional risks to them.
If they traveled on the later flight in early 2025, there would be time to deliver the appropriate suits.
Simeon Barber, a space scientist at the Open University, told BBC News that either way, it seems “we are heading inexorably towards a return on Space X’s” crafts.
“It seems that there are decision-makers at Nasa who are unconvinced that a safe return can be guaranteed,” he said.
Boeing has said repeatedly that it has full confidence that Starliner can bring the two astronauts safely home.
On Wednesday, officials were asked over and over what they might learn in the next weeks that would reassure them the astronauts would return safely on Starliner.
They did not answer the questions, but said a “major discussion” was happening at Nasa about how to return the crew.
The agency reiterated that it has “confidence” in Starliner and that the machine could be used to return the astronauts home in an emergency.
Boeing and SpaceX were awarded billion-dollar contracts by Nasa to provide commercial space flights for its astronauts.
So far SpaceX has sent nine crewed flights to space for Nasa, but this is Boeing’s first attempt at a crewed mission.
It would be a major embarrassment to Boeing if the two astronauts were forced to return on a SpaceX craft, wearing SpaceX suits.
Nasa officials also said they have brought in external experts in propulsion systems to analyse data from the troubled craft.
They will continue analysis before making a decision.
