In his one flight, Carpenter missed his landing by 288 miles, leaving a nation on edge for an hour as it watched live and putting Carpenter on the outs with his NASA bosses. So Carpenter found a new place to explore: the ocean floor.
He was the only person who was both an astronaut and an aquanaut, exploring the old ocean and what President John F. Kennedy called "the new ocean" — space.
NASA Administrator Charles Bolden said Thursday that Carpenter "was in the vanguard of our space program — the pioneers who set the tone for our nation's pioneering efforts beyond Earth and accomplished so much for our nation. ... We will miss his passion, his talent and his lifelong commitment to exploration."
Life was an adventure for Carpenter and he said it should be for others: "Every child has got to seek his own destiny. All I can say is that I have had a great time seeking my own."
The launch into space was nerve-racking for the Navy pilot on the morning of May 24, 1962.
"You're looking out at a totally black sky, seeing an altimeter reading of 90,000 feet and realize you are going straight up. And the thought crossed my mind: What am I doing?" Carpenter said 49 years later in a joint lecture with Glenn at the Smithsonian Institution.
For Carpenter, the momentary fear was worth it, he said in 2011: "The view of Mother Earth and the weightlessness is an addictive combination of senses."
For the veteran Navy officer, flying in space or diving to the ocean floor was more than a calling. In 1959, soon after being chosen one of NASA's pioneering seven astronauts, Carpenter wrote about his hopes, concluding: "This is something I would willingly give my life for."
"Curiosity is a thread that goes through all of my activity," he told a NASA historian in 1999. "Satisfying curiosity ranks No. 2 in my book behind conquering a fear."
Even before Carpenter ventured into space, he made history on Feb. 20, 1962, when he gave his Glenn sendoff. It was a spur of the moment phrase, Carpenter later said.
"In those days, speed was magic because that's all that was required ... and nobody had gone that fast," Carpenter explained. "If you can get that speed, you're home-free, and it just occurred to me at the time that I hope you get your speed. Because once that happens, the flight's a success."
Three months later, Carpenter was launched into space from Cape Canaveral, Fla., and completed three orbits around Earth in his space capsule, the Aurora 7, which he named after the celestial event. It was just a coincidence, Carpenter said, that he grew up in Boulder, Colo., on the corner of Aurora Avenue and 7th Street.
His four hours, 39 minutes and 32 seconds of weightlessness were "the nicest thing that ever happened to me," Carpenter told a NASA historian. "The zero-g sensation and the visual sensation of spaceflight are transcending experiences and I wish everybody could have them."