Sunita Williams, Butch Wilmore stuck in 'mini city in space' till July: How Nasa plans to bring them back?

On Friday, Nasa announced a further delay in Starliner's return

Sunita Williams and Butch Wilmore -- the two astronauts testing out Boeing's new Starliner aircraft -- may have to wait longer for their return to Earth as the vessel is facing multiple challenges. The capsule has reportedly encountered five helium leaks, five maneuvering thruster failures and a propellant valve issue since its launch on June 5, requiring the crew in space more time than anticipated.

The exact date of return of the capsule, docked at International Space Station (ISS), has not been mentioned by Nasa yet. While the mission was supposed to last for eight days, the return date was pushed after multiple issues were encountered by engineers. After being rescheduled for June 26, it is now uncertain when Williams and her crewmate will begin their journey back to Earth.

On Friday, Nasa announced a further delay in Starliner's return. Mission managers are evaluating future return opportunities following the station’s two planned spacewalks on June 24 and July 2, it said in a statement.

“We are taking our time and following our standard mission management team process,” said Steve Stich, manager of Nasa’s Commercial Crew Program. “Starliner is performing well in orbit while docked to the space station,” Stich said, adding that the additional time would yield “valuable insight” into system upgrades for future missions.

As per Stich, Starliner can stay docked at the ISS which is often decsribed as "mini city in space" for up to 45 days. However, if absolutely required, such as if more problems come up that mission officials cannot fix in time, it could stay docked for up to 72 days, relying on various backup systems.

A person familiar with flight planning told Reuters that within Nasa, Starliner’s latest targeted return date is July 6. This would mean that the mission, which was originally targetted to be completed in eight days, would last a month.

A Daily Mail report has said that the US space agency could be forced to launch a rescue mission, and could tap Elon Musk’s SpaceX to carry it out.

“Given the current situation with the Starliner, it is possible that Nasa could decide to use an alternative spacecraft, like SpaceX’s Crew Dragon, to bring the astronauts home safely,” said Katsuo Kurabayashi, professor of aerospace engineering at New York University.

“As far as I can tell at this point, the recent delay of the mission to July alone shouldn’t raise serious concerns leading to another highly challenging rescue mission or the future abandonment of Starliner-based missions,” the professor added.

The last time a Nasa astronaut needed an alternative ride home came in 2022, when Russia's Soyuz capsule sprang a coolant leak after delivering to the station two cosmonauts and American astronaut Frank Rubio.

This is Starliner's first mission to orbit carrying astronauts - the final test needed before Nasa can certify it as the US space agency's second ride to the ISS. It would join SpaceX's Crew Dragon, which has dominated the government and nascent private markets for human spaceflight amid Starliner's years-long delays.