NASA astronauts Butch Wilmore and Suni Williams returned to Earth in one of Elon Musk's SpaceX capsules on Tuesday, splashing down off Florida nine months after what originally was to be a weeklong stay on the International Space Station.

The re-entry began when Wilmore and Williams strapped inside their Crew Dragon spacecraft along with two other astronauts and undocked from the ISS at 1.05 am ET Tuesday to embark on a 17-hour trip to Earth, bidding farewell to the station's seven other astronauts.

The four-person crew, formally part of NASA's Crew-9 astronaut-rotation mission, re-entered Earth's atmosphere around 5:45 pm. ET. Using Earth's atmosphere and two sets of parachutes, the craft slowed its orbital speed of roughly 17,000 mph to 17 mph at splashdown off Tallahassee in the Gulf of America.

Dolphins circled the capsule as divers readied it for hoisting onto the recovery ship, which delighted many on social media.

"DOLPHINS are hanging around the astronauts splashdown!" wrote Matt Pieper on X.

"The Dolphins arrive right on schedule," posted Western Lensman.

Within an hour, the astronauts were out of their capsule, waving and smiling at the cameras while being taken away in stretchers for routine medical checks.

The two veteran NASA astronauts, who are both retired US Navy test pilots, had launched into space as Boeing Starliner's first crew in June for what was expected to be an eight-day test mission.

But issues with Starliner's propulsion system led to continuous delays for their return home when NASA decided to have them take a SpaceX craft back this year as part of the agency's crew-rotation schedule.

The replacement crew's brand-new SpaceX capsule still wasn't ready to fly, so SpaceX replaced it with a used one, moving things along by at least a few weeks.

The mission took an unexpected turn in late January when President Donald Trump asked SpaceX founder Elon Musk to speed up the astronauts' return and blamed the delay on the Biden administration.

"Congratulations to the @SpaceX and @NASA teams for another safe astronaut return! Thank you to @POTUS for prioritizing this mission!" Musk wrote on X on Tuesday evening.

"PROMISE MADE, PROMISE KEPT: President Trump pledged to rescue the astronauts stranded in space for nine months. Today, they safely splashed down in the Gulf of America, thanks to @ElonMusk, @SpaceX, and @NASA," the White House X account posted.

Veteran reporter Geraldo Rivera wrote on X: "Musk brought the astronauts back. Boeing couldn't. NASA didn't. SpaceX rocks."

Wilmore, 62, and Williams, 59, ended up spending 286 days in space — 278 days longer than anticipated when they launched. They circled Earth 4,576 times and traveled 121 million miles (195 million kilometers) by the time of splashdown.

"On behalf of SpaceX, welcome home," radioed SpaceX Mission Control in California.

"What a ride," replied Hague, the capsule's commander. "I see a capsule full of grins ear to ear."

NASA hired SpaceX and Boeing after the shuttle program ended, in order to have two competing US companies for transporting astronauts to and from the space station until it's abandoned in 2030.

By then, the station will have been up there more than three decades; the plan is to replace it with privately run stations so NASA can focus on moon and Mars expeditions.

The ISS, about 254 miles (409 km) in altitude, is a football field-sized research lab that has been housed continuously by international crews of astronauts for nearly 25 years, a key platform of science diplomacy managed primarily by the US and Russia.

Wilmore and Williams said that they didn't mind spending more time in space, but acknowledged it was tough on their families.

Wilmore said he missed most of his younger daughter's senior year of high school; his older daughter is in college.

Williams had to settle for internet calls from space to her husband, mother and other relatives.

"We have not been worried about her because she has been in good spirits," said Falguni Pandya, who is married to Williams' cousin. "She was definitely ready to come home."

Agencies contributed to this story.