Washington: A pair of astronauts stuck aboard the International Space Station (ISS) for over nine months may have to wait even longer to return to Earth, as the launch of their replacements was delayed due to a technical issue.

The Falcon 9 rocket carrying NASA-SpaceX's Crew-10 mission was initially scheduled to launch from Florida’s Kennedy Space Center on Wednesday at 7:48 pm (2348 GMT). However, with just 45 minutes left on the countdown clock, the launch was scrubbed due to a hydraulic system issue on the ground. "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 Federal Aviation Administration has indicated that the next potential launch opportunity for Crew-10 is Thursday, with a backup launch scheduled for Friday.

NASA astronauts Butch Wilmore and Sunita Williams have been stranded aboard the ISS since June 2024, after their Boeing Starliner spacecraft encountered propulsion issues and was deemed unfit for their return. The spacecraft returned to Earth without the crew, leaving Wilmore and Williams to remain in space. Originally assigned to an eight-day mission, the two were reassigned to the Crew-9 mission after its astronauts arrived in September aboard a SpaceX Dragon capsule. This spacecraft, which typically carries four astronauts, only brought two to accommodate Wilmore and Williams.

The Crew-9 spacecraft, which remains docked at the ISS, cannot return to Earth until Crew-10's replacement spacecraft arrives. "We came up prepared to stay long, even though we plan to stay short," Wilmore said in a recent news conference. "That's what your nation's human space flight program is all about, planning for unknown, unexpected contingencies."

The Crew-9 astronauts had been scheduled to depart on Sunday, weather permitting, with an ocean splashdown off the Florida coast. However, the uncertainty surrounding Crew-10’s launch timeline has raised questions about whether that schedule is still viable.

In addition to Wilmore and Williams, the return flight will also carry NASA astronaut Nick Hague and Russian cosmonaut Aleksandr Gorbunov aboard the SpaceX Dragon capsule.

Despite the prolonged stay of the American astronauts becoming a political issue, cooperation between the U.S. and Russia continues in space, with cosmonauts travelling to the ISS aboard SpaceX Crew Dragons and astronauts travelling on Soyuz capsules launched from Kazakhstan. The situation has sparked debate, with former President Donald Trump and his close advisor, Elon Musk, accusing President Joe Biden's administration of abandoning the astronauts. Musk suggested he had offered a "rescue" mission, although specifics have not been provided.

The issue recently sparked a heated online exchange between Musk and Danish astronaut Andreas Mogensen, whom Musk called a slur for mentally disabled people. Several retired astronauts quickly came to Mogensen's defense.

However, one astronaut who backed Musk was Wilmore, who offered contradictory statements in last week's press conference.

"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 mission consists of NASA astronauts Anne McClain and Nichole Ayers, Japan’s Takuya Onishi, and Russia's Kirill Peskov. McClain, who will command the mission, is 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. 
AFP inputs