The Artemis II capsule and its four-member crew streaked through Earth's atmosphere and safely splashed down in the Pacific Ocean after nearly ten days in space, capping the first voyage by humans to the vicinity of the moon in over half a century.
NASA's gumdrop-shaped Orion capsule, dubbed Integrity, parachuted gently into the sea off the Southern California coast shortly after 5pm PT (1am Irish time), concluding a mission that took the astronauts deeper into space than anyone had flown before.
The Artemis II flight, traveling a total of 1,117,515 km across two Earth orbits and a climactic lunar flyby some 252,000 miles away, was the debut crewed test flight in a series of Artemis missions that aim to start landing astronauts on the lunar surface starting in 2028.
Watch: Artemis II splashes down after historic moon mission
'Perfect bullseye'
The splashdown, under partly cloudy skies about two hours before sunset, was carried by live video feed in a NASA webcast.
"A perfect bull's eye splashdown for Integrity and its four astronauts," NASA commentator Rob Navias said moments after the landing.
"We are stable one - four green crew members," mission commander Reid Wiseman radioed just after splashdown, signaling the capsule was steady and that all four astronauts were in good shape.
It took NASA and U.S. Navy recovery teams took less than two hours to secure the floating capsule and retrieve the four crew members - US astronauts Wiseman, 50, Victor Glover, 49, and Christina Koch, 47, along with Canadian astronaut Jeremy Hansen, 50.
NASA reported that a navy medical officer who briefly checked the astronauts aboard the capsule found them all to be healthy.
The crew's homecoming cleared a critical final hurdle for the Lockheed Martin-built Orion spacecraft, proving it would withstand the extreme forces of re-entry from a lunar-return trajectory.
It followed a white-knuckle, 13-minute fiery plunge through Earth's atmosphere, generating frictional heat that sent temperatures on the capsule's exterior soaring to some 2,760 degrees Celsius.
At the peak of re-entry stress, as expected, intense heat and air compression formed a red-hot sheath of ionized gas, or plasma, that engulfed the capsule, cutting off radio communications with the crew for several minutes.
The tension broke as contact was re-established and two sets of parachutes were seen billowing from the nose of the free-falling capsule, slowing its descent to about 25kph before Orion gently hit the water.
Once Navy divers had attached a floating collar to stabilise the capsule, the four astronauts, still wearing their orange flight suits, were helped onto an inflatable raft. From there,they were hoisted one by one to helicopters hovering overhead and flown a short distance to a nearby Navy amphibious transport vessel, the John P. Murtha, for further medical examination.
Mr Glover and Ms Koch smiled broadly and waved toward cameras as they sat on the edge of a helicopter door on the flight deck.
The crew was expected to spend the night aboard the ship and be flown to Houston, where they will be reunited with family, NASA said.
It was expected to take NASA and US Navy teams took about an hour to secure the floating capsule and assist the four astronauts out of the vehicle and fly them to a nearby recovery shop to undergo an initial medical checkup.
Stepping stone to Mars
The quartet blasted off from Cape Canaveral, Florida, on 1 April, lofted into an initial Earth orbit by NASA's giant Space Launch System rocket before sailing on for a rare journey around the far side of the moon.
In so doing, they became the first astronauts to fly in the vicinity of Earth's only natural satellite since the Apollo program of the 1960s and '70s.
Mr Glover, Ms Koch and Mr Hansen also made history as the first Black astronaut, the first woman and first non-US citizen, respectively, to take part in a lunar mission.
At the flight's peak, the Artemis astronauts reached a point 252,756 miles from Earth, exceeding the previous record of roughly 248,000 miles set in 1970 by the crew of Apollo 13.
The voyage, following the uncrewed Artemis I test flight around the moon by the Orion spacecraft in 2022, marked a critical dress rehearsal for a planned attempt later this decade to land astronauts on the lunar surface for the first time since Apollo 17 in late 1972.
The ultimate goal of the Artemis program is to establish a long-term presence on the moon as a stepping stone to eventual human exploration of Mars.
In a historical parallel to the Cold War era of Apollo, the Artemis II mission has played out against a backdrop of political and social turmoil, including a US military conflict that has proven unpopular at home.
Unlike the Apollo era, when the United States was racing to land astronauts on the moon ahead of the Soviet Union, the Artemis program is seeking to beat China.
For many in a global audience captivated by the latest moonshot, it reaffirmed the achievements of science and technology at a time when big tech has become widely distrusted, even feared.
Opinion polling showed broad public support for the aims of the mission.
The return to Earth put the Orion spacecraft through a critical test of its heat shield, which sustained an unexpected level of scorching and stress on re-entry during its 2022 test flight.
As a result, NASA engineers altered the descent trajectory for Artemis II in order to reduce heat buildup and lower the risk of the capsule burning up.
Last week's successful launch was a major milestone for the SLS rocket, handing its principal contractors, Boeing and Northrop Grumman, long-sought validation that the launch system, more than a decade in development, was ready to safely fly humans to space.
