The crew from the SpaceX Dragon shuttle have been extracted safely after a morning splashdown.
Two NASA astronauts stranded in orbit for nine months have tasted fresh air again after they left their shuttle back to Earth this morning.
A live-stream from NASA showed the SpaceX shuttle splashing down off the coast of Tallahassee, Florida, US, just before 9pm.
The SpaceX crew monitoring the splashdown erupted in cheers as the shuttle landed.
"On behalf of SpaceX, welcome home," the ground crew told the four astronauts aboard.
Shuttle captain Nick Hague said there were "four big smiles" on the faces of the crew.
That crew included Butch Wilmore and Suni Williams, who found themselves stranded on the International Space Station after Boeing rocket faults stretched their week-long space voyage into nine months.
The journey home from space took about 17 hours, with the astronauts now waiting about 30 minutes for recovery ships to reach them.
https://twitter.com/SpaceX/status/1902117509798465910?ref_src=twsrc%5EtfwThe shuttle was pristine white when it departed the ISS, but landed in the ocean discoloured and scorched after re-entry.
Recovery boats tested the shuttle for hypergolic fumes - a combination of a fuel and an oxidizer that ignites immediately upon contact - and began the process of preparing the vessel for removal from the oval.
The parachutes were also recovered.
The astronauts remained inside the shuttle while awaiting recovery, but were kept cool by an on-board air conditioner and remained in contact with the outside world through their communications system.
READ MORE: Prince Harry's visa records to be made public amid claims about drug use
NASA public relations officer Jaden Jennings, who is on board the main recovery vessel, said the splashdown was "nothing short of spectacular".
"I think I speak for all of us on the ship when I say a new core memory was made for us today," she said.
A pod of dolphins surfaced around the shuttle amid the early recovery.
After recovery by the vessel Megan, named for astronaut K Megan McCarthy, the side portal was depressurised and opened, and one by one the astronauts were helped out and onto stretchers.
It is standard procedure for all returning astronauts to undergo medical checks.
They'll be flown by helicopter from the ship to an airport, where they'll embark on a plane to the NASA space centre in Houston, Texas, for a post-launch assessment.
Nine months in space
Williams and Wilmore expected to be gone just a week or so after launching on Boeing's new Starliner crew capsule on June 5.
So many problems cropped up on the way to the space station that NASA eventually sent Starliner back empty and transferred the test pilots to SpaceX, pushing their homecoming into February.
Then SpaceX capsule issues added another month's delay.
READ MORE: Stuck in space: What happens to your body if you're stuck in space too long?
Sunday's arrival of their relief crew meant Wilmore and Williams could finally leave.
They checked out with NASA's Nick Hague and Russia's Alexander Gorbunov, who arrived in their own SpaceX capsule last fall with two empty seats reserved for the Starliner duo.
"We'll miss you, but have a great journey home," NASA's Anne McClain called out from the space station as the capsule pulled away 418km above the Pacific.
Jennings said the two astronauts had undergone extensive training for returning on a SpaceX capsule.
Stranded in space
While other astronauts had logged longer spaceflights over the decades, none had to deal with so much uncertainty or see the length of their mission expand by so much.
Wilmore and Williams quickly transitioned from guests to full-fledged station crew members, conducting experiments, fixing equipment and even spacewalking together.
With 62 hours over nine spacewalks, Williams set a new record: the most time spent spacewalking over a career among female astronauts.
READ MORE: Trump ending Secret Service protection for Biden's adult children
Both had lived on the orbiting lab before and knew the ropes, and brushed up on their station training before rocketing away.
Williams became the station's commander three months into their stay and held the post until earlier this month.
Both retired Navy captains, Wilmore and Williams stressed they didn't mind spending more time in space — a prolonged deployment reminiscent of their military days.
But they acknowledged it was tough on their families.
Wilmore, 62, missed most of his younger daughter's senior year of high school; his older daughter is in college.
Williams, 59, had to settle for internet calls from space to her mother.
They'll have to wait until they're off the SpaceX recovery ship and flown to Houston before the long-awaited reunion with their loved ones.
DOWNLOAD THE 9NEWS APP: Stay across all the latest in breaking news, sport, politics and the weather via our news app and get notifications sent straight to your smartphone. Available on the Apple App Store and Google Play.
The $8 billion plan to make your energy bill cheaper
Teen charged after allegedly grabbing crocodile at tourist park
CCTV captures high-speed smash that left driver fighting for life
Homes inundated, roads swamped after state smashed by 300mm of rain
Ex-boyfriend tried to lure victim's dad to school murder site
Nurse wants alleged Israeli threat video tossed out
The worst Australian suburbs for making a profit on house sales
Learner driver killed, brother fighting for life after crash north of Sydney
The ugly federal election secret nobody is talking about
Australia's link to JFK assassination revealed in declassified files
Queensland town ups salary offer to $680,000 in second bid to find a GP
Man who stole $10 million toilet from palace used it the day before
Moment hot drink lands on driver's lap, leading to $79 million Starbucks payout
Women, children killed as Israel breaks Gaza ceasefire
Prince Harry's visa records to be made public amid claims about drug use
Meticulous stalking and practice runs before brutal school killing
What you can expect in next week's federal budget
Treasurer interrupted by protesters before giving grim budget warning
Nearly 100 galaxies revealed in first images from WA telescope
