France, April 12 -- The NASA spacecraft carrying four astronauts -- three Americans and one Canadian -- splashed down without a hitch off the California coast, capping the US space agency's crewed test mission that returned with spectacular images of the Moon.

"What a journey," said mission commander Reid Wiseman, who reported that the crewmembers -- himself along with Christina Koch, Victor Glover and Jeremy Hansen -- were "stable" and "green."

"They're in great condition, that's what that means," said Rob Navias, the NASA public affairs official who narrated their return on the agency's livestream.

Following an expected but nerve-wracking communications blackout during their high-stakes re-entry, Wiseman's voice triggered relief that...