Astronauts are stuck on International Space Station indefinitely after problems with Boeing Starliner

The two astronauts currently stuck on the International Space Station might not be able to come down until August, Nasa has said.

They were taken to the ISS on board Boeing ’s troubled Starliner capsule in June. Even before launch, the spacecraft ran into technical issues, and it has experienced a host of new ones since.

Sunita Williams and Butch Wilmore, the astronauts, were supposed to come back after around a week. But engineers have repeatedly delayed their return flight, because of safety concerns about the capsule.

Since then, they have been stuck indefinitely on the spacecraft, as engineers work to check whether the Starliner would be safe to return.

But in a new update, Nasa engineers said that the astronauts could be stuck until August. The crew on the ISS is supposed to rotate in mid-August, which is serving as something of a deadline for the plans.

The astronauts stuck in space have however said that they believe the spacecraft will allow for their safe return . “I have a real good feeling in my heart that this spacecraft will bring us home, no problem,” NASA astronaut ‘Suni’ Williams said during the test crew’s first news conference since docking to the ISS more than a month ago.

NASA’s commercial crew chief Steve Stich told reporters on Wednesday that “we’re taking our time” with the testing and that the results of the New Mexico thruster tests “are not quite what we would have hoped for.”

Stich said he hopes the testing will be completed by this weekend. Stich previously said this testing could last “a couple weeks,” followed by a detailed Nasa review of the data to inform the agency’s decision on letting Starliner fly the astronauts home.

Also docked to the space station is SpaceX’s Crew Dragon capsule that ferried four astronauts to the ISS in March, and a Russian Soyuz capsule that delivered three others in September. Stich acknowledged that at least one of those vehicles could provide an alternative ride home for Wilmore and Williams.

“We have a little bit more time to go through the data, and then make a decision as to whether we need to do anything different” with the return plan, Stich said. “But the prime option today is to return Butch and Suni on Starliner. Right now, we don’t see any reason that wouldn’t be the case.”

Starliner is approved to stay docked to the ISS for 45 days - which would be July 21 - or up to 90 days using various backup systems and depending largely on the health of its lithium ion batteries, which have caused concerns in the past.

Though Nasa and Boeing have said Starliner is capable of returning the astronauts to Earth in the event of an emergency on the ISS, the capsule is not approved to fly home under normal, non-emergency circumstances until its thruster issues are resolved or at least better understood.

A Russian satellite last month broke apart into some 180 pieces of debris near the space station’s orbit and forced astronauts into their various docked spacecraft, including Wilmore and Williams getting into Starliner, to prepare for a potential escape. Boeing cited the event as an example of Starliner‘s readiness to return home if absolutely necessary.

Mark Nappi, Boeing’s Starliner chief, told reporters that such an emergency return scenario would simply involve Starliner undocking from the station and safely returning the crew to Earth, despite questions about the thrusters.

“I feel confident that if we had to, if there was a problem with the International Space Station, we can get in our spacecraft, and we can undock, talk to our team, and figure out the best way to come home,” Williams said.

Additional reporting by agencies