Two astronauts will be at the ISS for longer than planned, following issues with Boeing’s Starliner.

The spacecraft has experienced helium leaks and thruster failures during its first crewed launch.

NASA and Boeing have pushed back Starliner’s return to June 26 to review data from the mission.

Two NASA astronauts have been left waiting to return home from the International Space Station because of issues with Boeing’s Starliner spacecraft.

NASA and Boeing announced on Tuesday that Starliner’s return had been delayed to June 26 after the troubled vessel’s first crewed launch was hampered by technical issues.

It’s the latest delay to hit the Starliner mission and means an ISS mission that was expected to last eight-10 days is now extended to at least 20 for astronauts Butch Wilmore and Suni Williams.

The space capsule had a difficult time docking with the ISS, with five thrusters failing on approach, though four were subsequently recovered.

NASA said last week that ground teams were also assessing the potential impact of five small helium leaks.

In a press briefing on Tuesday, NASA and Boeing officials said that Starliner had plenty of helium left and that they felt “comfortable” about the craft’s ability to re-enter Earth’s atmosphere safely.

They added, however, that they were taking time to review data from the launch and docking before giving Starliner the green light to return home.

Starliner’s first crewed launch, which took place on June 5, was delayed multiple times because of technical concerns.

The launch was a crucial moment for the US aviation giant, which is attempting to challenge SpaceX’s stranglehold on the commercial space industry.

SpaceX has been transporting astronauts to and from the ISS since 2020, but Boeing, the other company selected by NASA for the task in 2014, has lagged behind.

SpaceX founder Elon Musk criticized Boeing about a month before Starliner’s launch, writing on X that the company had “too many non-technical managers.”

The issues with Starliner come at a bad time for Boeing, which is grappling with new safety concerns over its 737 Max after a door plug on an Alaska Airlines passenger plane detached mid-flight in January.

Boeing and NASA did not immediately respond to a request for comment made outside normal working hours.