Their return marked the end of the first crew rotation mission to the station by the Crew Dragon spacecraft.
Musk won. Bezos was not happy.
The Endeavour capsule, also making its second flight, was launched into space on Friday atop a SpaceX Falcon 9 rocket from NASA's Kennedy Space Center in Florida.
The helmeted astronauts, dressed in their custom white flight suits and black boots, walked out of the space center's operations building a little over three hours prior to launch time, waving to onlookers and bidding goodbye to loved ones.
"The technology we've developed is part of a value chain that will allow permanent bases to be established outside the limits of planet earth."
The unprecedented extraction of oxygen, literally out of thin air on Mars, was achieved Tuesday by an experimental device aboard Perseverance, a six-wheeled science rover.
The robot rotorcraft was carried to the red planet strapped to the belly of NASA's Mars rover Perseverance, a mobile astrobiology lab that touched down in February.
The mission will be the first by the US space agency since its Apollo mission, the report said.
"If they hit their milestones, we have a shot at 2024," Steve Jurczyk, NASA's acting administrator, said during the announcement.