Mission to replace stranded NASA astronauts delayed after last-minute technical issue

A mission to return two astronauts stranded on the International Space Station has been delayed over a last-minute technical issue.

Two US astronauts stranded on the International Space Station for over nine months will have to wait longer to return home after a SpaceX mission to replace them was delayed.

The Falcon 9 rocket was set to take off from Florida’s Kennedy Space Center with Crew-10 astronauts at 7:48pm on Wednesday US time (10.48am Thursday AEDT).

But with about 45 minutes left on the countdown clock and all four crew members strapped in, the rocket’s launch pad experienced a technical issue.

“There was an issue with the hydraulic system on the ground side,” NASA launch commentator Derrol Nail said, adding that “everything was fine with the rocket and the spacecraft itself.”

The Falcon 9 rocket was set to take off from Florida’s Kennedy Space Center on Wednesday evening local time. Picture: X@SpaceX

Crew-10 were ready for take off but the mission was scrubbed. Picture: X@SpaceX

SpaceX did not immediately announce a new launch date. But a Federal Aviation Administration space advisory showed the next launch opportunity will be on Thursday, with a backup on Friday, US time.

The crew – consisting of two US astronauts and astronauts from Japan and Russia – will replace Butch Wilmore and Suni Williams who have been stranded aboard the International Space Station since June after their Boeing Starliner ran into several technical issues.

The two veteran astronauts took off aboard the Starliner as part of the vessel’s first crewed mission on June 5, in what was originally meant to be eight days in orbit.

Butch Wilmore and Suni Williams have been stranded aboard the International Space Station since June. Picture: NASA/AFP

But the spacecraft developed propulsion issues and was deemed unfit for their return.

Instead, it returned to Earth empty last year with Wilmore and Williams now set to fly home aboard a SpaceX Dragon, which arrived at the space station in September.

The spacecraft carried only two crew members instead of the usual four to make room for Wilmore and Williams.

But it can only leave the space station and return to Earth after Crew-10 arrives, leaving Williams and Wimore’s journey home delayed.

NASA astronaut Nick Hague and Russian cosmonaut Aleksandr Gorbunov will also be aboard the returning Dragon capsule.

“We came up prepared to stay long, even though we plan to stay short,” Wilmore said at a press conference last week.

“That’s what your nation’s human space flight program is all about, planning for unknown, unexpected contingencies.”

It comes after US President Donald Trump and SpaceX CEO Elon Musk called for the astronauts to be brought back ahead of NASA’s scheduled return date of March 26.

The pair have accused ex-president Joe Biden’s administration of abandoning the astronauts.

Mr Musk has suggested, without providing specifics, that he had offered Mr Biden a “rescue” mission outside of the routine crew rotations.

The issue recently sparked a heated online exchange between Mr Musk and Danish astronaut Andreas Mogensen, whom Mr Musk called an “idiot” and a derogatory term online.

Several retired astronauts quickly came to Mogensen’s defence.

One astronaut who backed Mr Musk however was Mr Wilmore, who offered contradictory statements in last week’s press conference.

Mr Wilmore and Ms Williams are now set to fly home aboard a SpaceX Dragon. Picture: Miguel J. Rodriguez Carrillo/AFP

“I can only say that Mr. Musk, what he says is absolutely factual,” he said, seemingly endorsing the SpaceX founder’s version of events, before adding “politics is not playing into this at all.”

The Crew-10 team consists of NASA astronauts Anne McClain and Nichole Ayers, Japan’s Takuya Onishi, and Russia’s Kirill Peskov.

Ms McClain, the mission’s commander, will be making her second trip to space.

“I’m looking forward to breaking bread with those guys, talking to them, giving them big hugs,” she said of Wilmore and Williams.

During their mission, the new crew will conduct a range of scientific experiments, including flammability tests for future spacecraft designs and research into the effects of space on the human body.

Originally published as Mission to replace stranded NASA astronauts delayed after last-minute technical issue