NASA and SpaceX are aiming for liftoff at 7:03 pm (2303 GMT) of a Falcon 9 rocket carrying a Dragon spacecraft on the Crew-10 mission, after a technical issue with ground systems prevented launch on Wednesday.

Crew-10 carries an international four-member team set to carry out science experiments on the orbital lab -- but the greater interest comes from the fact that their arrival enables others to depart.

NASA duo Butch Wilmore and Suni Williams, veteran astronauts and ex-Navy pilots, have been stuck aboard the ISS since June after the Boeing Starliner spacecraft they were testing on its maiden crewed flight developed propulsion issues and was deemed unfit to fly them back.

The Starliner instead returned empty, without experiencing further major issues.

What was meant to have been a days-long trip for Wilmore and Williams has now lasted beyond nine months.

Their stay has been longer than the standard ISS rotation for astronauts of roughly six months -- but still much shorter than the US space record of 371 days set by NASA astronaut Frank Rubio from 2022-2023, or the world record held by Russian cosmonaut Valeri Polyakov, who spent 437 continuous days aboard the Mir space station from 1994-1995.

Still, the unexpected nature of their prolonged stay away from their families -- they had to receive additional clothing and personal care items because they hadn't packed enough -- has garnered interest and sympathy.

It's also become something of a political flashpoint of late, as President Donald Trump and his close advisor, Elon Musk -- who leads SpaceX -- have suggested that former president Joe Biden "abandoned" the pair intentionally and rejected a plan to bring them back sooner.

- 'Maybe they love each other' -

That claim caused uproar in the space community, especially since Musk did not provide any specifics.

The plan for the duo's return has been unchanged ever since they were reassigned to SpaceX's Crew-9, which arrived in September aboard another Dragon carrying only two crew members -- instead of the usual four -- to make room for Wilmore and Williams.

Danish astronaut Andreas Mogensen pointed this out on X, only for Musk to taunt him with a slur for mentally disabled people.

Some retired astronauts rushed to Mogensen's defense -- while Wilmore appeared to back Musk, saying his comments must have been "factual" even though he was not privy to any details.

Trump himself has been making waves for his bizarre comments, referring to Williams, a decorated former Naval captain, as "the woman with the wild hair" and even suggesting the two may have fallen in love.

"They've been left up there -- I hope they like each other, maybe they love each other, I don't know," he said during a recent White House press conference.

Only once the Crew-10 spaceship arrives can the Crew-9 spaceship leave. Handover periods generally last a few days, and an earlier plan would have seen Crew-9 depart on Sunday for splashdown off the Florida coast -- though it's not clear if that timeline is still feasible.

Along with Wilmore and Williams, NASA astronaut Nick Hague and Russian cosmonaut Aleksandr Gorbunov will also be aboard the returning Dragon capsule.

Space remains an area of cooperation between the United States and Russia despite the Ukraine conflict, with cosmonauts traveling to the ISS aboard SpaceX Crew Dragons and astronauts doing the same via Soyuz capsules launched from Kazakhstan.

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