A pair of American astronauts may be asked to wait six more months in space before returning to earth, NASA officials acknowledged Wednesday.

Barry Wilmore and Sunita Williams flew to the International Space Station (ISS) aboard a Boeing spacecraft in June, but have been stuck indefinitely in space. Engineers on Earth are attempting to diagnose leaks that forced failures to the spacecraft’s thrusters.

The scheduled eight day journey has ballooned into a two month trip, and NASA officials said they’re considering altering course completely, dropping the Boeing Starliner back to Earth empty, and bringing the astronauts home in February 2025, eight months later than planned.

"We heard from a lot of folks that had concern," said Ken Bowersox, who helps lead space operations for NASA. "We heard from enough voices that the decision was not clear."

The astronauts are now facing an extended stay aboard the ISS, but so far haven’t voiced any complaints. They probably don’t mind, according to Dan Riskin, a science and technology expert.

"This is what they trained for, this is what they live for," he said. "They are made of something different from the rest of us."

Both are veteran astronauts who’ve been to the ISS before. The pair aren’t just sitting on their hands — they’ve recently received a new supply of food and clothes and are working on scientific research with the rest of the ISS crew.

NASA

But the crew can’t be kept on the space station forever, and on Wednesday NASA officials opened the door further to having the crew return on a SpaceX craft — Boeing’s space rival.

"If that does happen, is Starliner dead in the water, or is there some way to resurrect that program?" said Riskin.

"They are really taking their time and [that] is the conversation right now that’s happening internally at NASA."

Boeing has spent more than a billion dollars on their Starliner program. This mission was set to be a demonstration of their spacecraft’s capacity to ferry astronauts to and from the ISS, something that SpaceX has been doing for four years.

While Wilmore and Williams have been stuck in space, engineers at Boeing have been testing and working to diagnose issues.

Latest tests, however, have not increased confidence that the Starliner craft can meet NASA’s safety standards for a return trip.

"We knew the test flight would be riskier," said Steve Stich, who helps oversee the commercial crew program that works with both Boeing and SpaceX.

"Now that we have had the helium leaks on orbit and the thruster fail-off, some of the team don’t see that level of risk as something we should entertain."

Riskin said NASA’s safety standards are quite high, and although Starliner suffered thruster failures, there was not big risk to the safety of the astronauts.

"They might be missing some family meals that they’d like to have, but on the other hand, these are astronauts and they love being in space."

With files from Reuters