John Glenn became the first American to orbit Earth in 1962

John H. Glenn became the first American to orbit Earth on February 20, 1962, circling the planet three times in 4 hours, 55 minutes and 23 seconds aboard Friendship 7 on NASA’s Mercury-Atlas 6 mission, at about 17,500 mph and roughly 160 miles up.

The flight was a catch-up, not a lead. Yuri Gagarin had orbited Earth ten months earlier, and the Soviets had since kept a cosmonaut in space for a full day. Glenn’s own launch slipped repeatedly: a first attempt on January 27 was halted 13 minutes before liftoff by thick cloud, and on launch day he spent nearly four hours strapped in the capsule before the Atlas fired at 9:47 a.m.

In orbit he saw the “fireflies” (ice particles glinting in the sunrise), ate the flight’s only food, a tube of applesauce, and took over steering when the capsule’s automatic control system began letting it drift.

The famous heat-shield scare came from a signal, not a fault. At the start of his second orbit, controllers saw a reading that the landing bag had deployed, which would mean the heat shield behind it was loose. Engineers assumed the signal was erroneous but took no chances: Glenn would keep the retrorocket pack strapped on after firing, hoping its straps would hold the shield in place. He was not told outright, only repeatedly asked to check that the landing-bag switch was off.

Re-entering, he called it “a real fireball outside” as pieces of the pack burned past his window. It was a false alarm: the signal proved faulty, and the shield had been secure all along. Friendship 7 splashed down 41 miles west and 19 miles north of its target near Grand Turk Island, so the destroyer USS Noa, not the planned carrier, hauled it aboard 21 minutes later.