The crew reported they were feeling well after their arrival back on Earth following a nearly six-month mission aboard the International Space Station, NASA said.

The capsule splashed down at 2:56 am (0656 GMT) in the dark in the Gulf of Mexico off Panama City after a six-and-a-half-hour flight from the ISS, night-vision images relayed by NASA's WB-57 high-altitude research aircraft showed.

Teams aboard the Go Navigator recovery ship retrieved the capsule and hoisted it onto the deck about half an hour later. It was the first nighttime splashdown for NASA since the crew of Apollo 8 arrived in the Pacific Ocean on December 27, 1968.

Commander Michael Hopkins was the first to emerge after the hatch was opened, doing a little jig as he set foot on deck, followed shortly after by fellow NASA astronaut Victor Glover.

"On behalf of Crew-1 and our families, we just want to say thank you ... It's amazing what can be accomplished when people come together. Y'all are changing the world. Congratulations. It's great to be back," Hopkins said in a NASA tweet.

NASA astronaut Shannon Walker and Japan's Soichi Noguchi were the other two aboard.

"Welcome home Victor, Michael, Shannon, and Soichi, and congratulations to the teams at NASA and SpaceX who worked so hard to ensure their safe and successful splashdown," said new NASA administrator Bill Nelson.

"We've accomplished another incredible spaceflight for America and our commercial and international partners. Safe, reliable transportation to the International Space Station is exactly the vision that NASA had when the agency embarked on the commercial crew program."

- 71 million miles -
The four astronauts went to space last November as the crew on the first fully operational mission to the ISS aboard a vehicle made by Elon Musk's SpaceX, which has become NASA's favored commercial transportation partner.

They traveled 71.2 million miles (114.6 million kilometers) during their 168 days in orbit (including 167 days aboard the space station), NASA said.

After medical checks, the four astronauts will be flown by helicopter to Pensacola to board a plane for Houston to be reunited with their friends and family, NASA said.

Seven astronauts remained on the ISS including a new crew of four who arrived on a different SpaceX craft last week.

"Thanks for your hospitality," Hopkins said earlier as the capsule undocked from the space station for its return journey. "We'll see you back on Earth."

Prior to that, two American astronauts made a test mission to the ISS in May and stayed for two months.

That was the first launch to the ISS from US soil since the end of the Space Shuttle program in 2011. It was also the first crewed mission run by a private company, as opposed to NASA.

Until then US astronauts had caught rides to the ISS aboard Russian spacecraft.

Astronauts splash down in Gulf of Mexico off Florida
Washington DC (UPI) May 2, 2021 - Astronauts from SpaceX's Crew-1 mission splashed down in U.S. waters at 2:57 a.m. Sunday, and crews worked to inspect the capsule and then bring it aboard a recovery ship.

The astronauts saw the Crew Dragon capsule Resilience undock from the International Space Station at 8:35 p.m. EDT Saturday and head for the nighttime splashdown off Florida about 6 1/2 hours later.

Shortly before 2 a.m. EDT, the capsule's thrusters performed a 16-minute burn to slow the spacecraft, removing it from orbit and head the astronauts toward their prime landing area. Clear weather and minimal winds at about 2 knots were called excellent for the splashdown.

At the time if left orbit, the capsule was moving at 16,500 mph, and it eventually slowed to about 16 mph, with the aid of parachutes, when it hit the water in the Gulf of Mexico off Panama City, Fla.

The splashdown was the first night return of a U.S. crewed capsule since Apollo 8's predawn landing in the Pacific Ocean on Dec. 27, 1968, with NASA astronauts Frank Borman, Jim Lovell and Bill Anders.

According to NASA, the Crew Dragon undocked autonomously and left the space station, with the capability to splash down at one of seven predetermined landing zones.

The primary sites chosen Friday were in the Gulf of Mexico off Panama City, Fla., followed by near Tampa, Fla.

The astronauts brought with them what the space agency calls "important and time-sensitive research."

The capsule flew robotically, which was the plan, crew commander Mike Hopkins said in a news conference Monday from the space station.

"Your landings are always fairly dynamic, particularly with the capsules like this, particularly when the chutes are opening, so that's always a little bit exciting," Hopkins said.

NASA astronauts Victor Glover and Shannon Walker, and Japan Aerospace Exploration Agency astronaut Soichi Noguchi will be in the capsule with Hopkins.

The Crew-1 mission marked the first time four people flew in a space capsule, and was only the second crewed launch for SpaceX and NASA's commercial crew program.

The best part of the mission was greeting the Crew-2 astronauts, who arrived on Saturday morning at the space station, Noguchi said at the press conference. That arrival boosted the population of the space station for a short while to 11 for the first time in years.

The Crew-1 mission was launched from Kennedy Space Center in Florida on Nov. 15, before vaccines for the COVID-19 pandemic became available. The crew members intend to be vaccinated in the coming weeks, the astronauts said.