Wallace Johnson -- who still flies planes with the Alameda Aero Club, even in his 90s -- began his career as a Navy sailor at only 16. Now, he's the world's leading expert at landing an Apollo spacecraft, even though he's never left Earth's atmosphere.
RELATED: Astronaut encourages Concord students to follow their dreams
As a test pilot for North American Aviation, he spent long hours running detailed simulations, and ultimately trained the astronauts who went to the moon.
"I have many, many hours of flying the capsule on the return flight, penetrating the earth's atmosphere," Johnson said. "If you came in too shallow, you would skip out, and if you came in too steep, you would burn up."
Newspapers called Johnson the "ground astronaut" -- which was more flattering than another nickname he was given.
"My wife called me a half-astronaut," Johnson confessed, lingering a bit too long on the first syllable of "astronaut."
Happy birthday to “the ground astronaut,” Wallace Johnson — who turns 93 tomorrow! I got to hear the incredible story of how he came to test spacesuits, design training programs and teach astronauts how to safely steer the Apollo capsule back to earth. pic.twitter.com/FcKxAM3RGO— Jonathan Bloom (@BloomTV) April 18, 2018
Johnson went to civilian pilot school even while continuing to serve as an enlisted man in the Navy.
RELATED: Former NASA astronaut visits East Bay high school students
He was offered a chance to attend the Navy's electronics school, and became the chief electronics technician aboard the USS Hornet -- a World War II aircraft carrier that's since been retired and turned into a museum just up the street from Johnson's home in Alameda.
It was his unusual combination of experience, with both electronics and airplanes, that made Johnson the perfect test pilot for North American Aviation, which built the command module for the Apollo space missions. They called on him in the wake of the fatal fire that killed three Apollo 1 astronauts.
"You can see here that i'm pretty worn out," Johnson said, showing us a color photograph from 1967. "I've been in and out of that capsule I don't know how many times."
The photo was one of a handful taken during the painstaking efforts to recreate the conditions of the Apollo 1 fire, with Johnson and two other test pilots in spacesuits, strapped into a simulator as engineers looked on. They ultimately found the electrical problem that likely started the fire, and the design flaw that kept the crew from opening the hatch.
Though a setback for the space program, the work to prevent another tragedy launched a whole new career for Johnson: testing spacesuits, designing control layouts, writing manuals and ultimately training astronauts.
RELATED: Astro Kate visits old Napa high school after trip to space
"They were just ordinary guys, when you really get right down to it," he said. "They were all brilliant, for one thing, i will say that."
Over the years, Johnson accumulated more than 60 astronauts' signatures in a copy of the book, "We Seven," about the pioneering Mercury manned space missions. Among the autographs are all seven Mercury astronauts, and the three who later died in Apollo 1.
Johnson attended three of the Apollo launches, but retired shortly after training Apollo 11 astronauts Neil Armstrong and Buzz Aldrin. He stayed home and watched their historic first steps on the moon from his living room -- glued to the TV along with the rest of the nation.
The passion for flight never left Johnson, who lives on his own, takes long walks and updates his blog regularly when he's not at the controls of an airplane.
"I'm still flying," he said. "That keeps me busy, and out of trouble."
Click here for more stories, photos, and video on space.