Seconds away from lift-off, astronaut John Glenn monitored the instruments in his cramped Mercury capsule, listening intently as fellow astronaut Scott Carpenter called out milestones in the final moments of a tense countdown.
John Glenn boards the Friendship 7 capsule in February 1962. Image credit: NASA
Earlier attempts to launch Glenn on America's first orbital spaceflight had been scrubbed by technical snags and bad weather. But this time around, the Atlas rocket, the Friendship 7 capsule, and the weather co-operated, clearing the way for the long-awaited, high-stakes attempt to reach orbit.
Millions across the nation and around the world hung on every word from mission control, gathered around radios and black-and-white television sets. Daily activity virtually ground to a halt while the drama played out in Florida.
In a blockhouse near the launchpad, legendary test conductor Thomas 'TJ' O'Malley pushed a button to start the final launch sequence, saying softly, "Good Lord ride all the way."
Carpenter famously added "Godspeed, John Glenn" as the nation held its collective breath. Seconds later, the countdown hit zero and the Atlas rocket, its main engine roaring and belching a brilliant plume of fiery exhaust, majestically climbed away from its Cape Canaveral launch pad.
"Roger, the clock is operating, we're under way!" Glenn called out.
It was 9:47am, 20 February, 1962 — 50 years ago on Monday — and the US had a new hero.
The space race
The Soviet Union had shocked the world on 4 October, 1957, when it successfully launched Sputnik, the world's first artificial satellite. The Russians followed that triumph by launching Yuri Gagarin into orbit on 12 April, 1961, the first human to fly in space.
Under enormous pressure to catch up with the Russians on the high frontier, NASA launched Alan Shepard on 5 May, 1961, and Virgil 'Gus' Grissom on July 21. But both of those flights aboard modest Redstone rockets were sub-orbital, up-and-down missions lasting about 15 minutes each.
Capitalising on their role as the early leader in what came to be known as the "space race," the Soviets launched cosmonaut Gherman Titov just a few weeks later on a 17-orbit mission that dwarfed NASA's accomplishments to that point.
"They beat us out. They gave us a double whammy," Carpenter said, recalling Glenn's flight 50 years later. "Not only did they get the honour of the first man in space, but they sent him... into orbital flight. That was a double whammy for them. Who knew that better than Al Shepard? He was very disappointed that Yuri robbed him of the first-man-in-space title... That only inspired all of us here to do better work."
Enter John Glenn
Enter John Glenn and Mercury Atlas 6.
The clean-cut Marine Corps test pilot, a veteran of 59 combat missions in World War 2 and 90 during the Korean War, was selected by NASA as one of the original seven Mercury astronauts.
– John Logsdon
Glenn, I think, radiated a sense of competence and, if you want, 'American-ness' that made him kind of ideally suited for the role of the first US person to go into orbit.
While many at the time believed Shepard's selection to fly the first sub-orbital mission put him at the top of NASA's astronaut hierarchy, it was Glenn who ultimately became the enduring face of the early space programme, riding the Atlas rocket into American history.
"We needed someone to symbolise that we weren't going to stay behind in space," said John Logsdon, a space policy analyst and an expert on the US space programme. "This was after a very bad '61 with the threat of war over Berlin and Kennedy's administration slow getting started and the country's mood was not great.
"Glenn, I think, radiated a sense of competence and, if you want, 'American-ness' that made him kind of ideally suited for the role of the first US person to go into orbit. He carried it off with such style, a combination of humility and grace."
Mercury Atlas 6 blasts off 20 February, 1962, boosting astronaut John Glenn into orbit. Image credit: NASA
Mercury Atlas 6
The Atlas rocket, a converted intercontinental ballistic missile, had its share of problems during testing, which added drama to Glenn's flight. Glenn laughed when asked recently whether he was nervous about riding it for the first time.
"I think the first 18 or 20 Atlases that fired, I think they had a 45-percent failure rate, that's the figure I remember," he said in an interview. "The first time they took us [the Mercury 7 astronauts] down there to see a booster launch, we'd never seen a launch, and they took us down for a night launch and the thing blew at high Q at 27,000 feet right over our heads. It looked like an atomic bomb going off.
"Anyway, they came back and improved the whole thing and had several straight successes and had the problems worked out before I got on the thing. But it was something we were very concerned about at the time."
As it turned out, Glenn's Atlas performed flawlessly, boosting his Friendship 7 capsule to 17,500 mph in about five minutes and 20 seconds. When the capsule separated from the rocket, it was programmed to immediately turn around, putting its heat shield forward, in case of a problem that might force an emergency re-entry.
Hitting zero G
"Zero G and I feel fine," Glenn, now weightless, reported from orbit. "Capsule is turning around. Oh, that view is tremendous!"
Glenn's memory of that day remains razor-sharp, telling CBS News that "it seems more like a couple of weeks ago to me, because that fight was pretty well indelibly impressed on my memory back in that time."
– John Glenn upon launch
Despite the fire and thunder associated with rocket launches, Glenn said the Atlas was "very gentle" at first because the thrust of the booster barely exceeded its weight. But as the propellants were consumed and the rocket got lighter, it steadily accelerated, pushing Glenn into his contoured seat with nearly eight times the normal force of gravity on the way to orbit.
"When I hit orbit up there, I said, I think it was 'zero G and I feel fine.' I think the next thing I said was 'that view is tremendous!' ... It was right after detachment from the booster, from the Atlas, that I turned around and it went immediately into retro attitude, which was nose down a little bit looking back along the flight path. I could look back clear across Florida and along the Gulf of Mexico, and it was beautiful. I couldn't believe the view."
Other than a relatively minor but persistent attitude control problem that prompted Glenn to fly the capsule manually, Friendship 7 performed smoothly as it raced around the planet, giving the astronaut spectacular views of the Earth below. He even enjoyed a salute from the residents of Perth, Australia, who turned on their lights as the capsule passed over.
Heat shield warning
But at the start of his second orbit, telemetry from a sensor indicated the spacecraft's heat shield was not locked down. If the telemetry was correct, the straps...
