On February 20th, 1962, after months of delays, NASA mission control hit the go button on the Mercury Atlas 6 mission. The enormous Atlas D rocket blasted out of Cape Canaveral with over 400,000 lbs. of force.
On top of this massive 94-foot-tall flying tower was attached the tiny Friendship 7 Mercury capsule. Aboard was astronaut John Glenn, one of the very first Americans in space and soon to be the first ever American to orbit the Earth.
It was a turning point for American confidence. Before Glenn took flight, the entire history of NASA manned spaceflight consisted of 2 suborbital flights, first by Alan Shepard and then Gus Grissom. And before that, a successful suborbital flight by a chimpanzee named Ham.
The Challenges of Orbital Space Flight
Suborbital spaceflight involved reaching altitude. Get your capsule up 62 miles above sea level, and you were considered to be in space. Shepard and Grissom both made it to at least 117 miles above sea level.
But orbital spaceflight required incredible speed as well. Previous manned missions used the smaller Redstone rocket, which was “only” able to reach about 8,000 miles per hour.
This new orbital flight meant adapting the Mercury capsule to fit the much larger Atlas D rocket to get more speed.
At the time the Atlas was the largest ICBM in the United States military arsenal, capable of transporting a 3,700 lb. nuclear warhead anywhere in the world. Modified to accept the Mercury capsule, the Atlas made 3 successful unmanned test launches along with 2 failures.
Notably, the Mercury Atlas 3 mission resulted in the rocket detonating directly above Cape Canaveral, raining burning material back down on the launch pad below.
It was only when a final test mission piloted by another chimpanzee, Enos, found success that Glenn’s pioneering human flight was given the go-ahead.
Godspeed, John Glenn
Up until Glenn stepped into the spacecraft, the mission was hit with delay after delay. The fuel tanks inside the Atlas rocket suffered constant problems, including leaks that would set back the launch weeks at a time.
And once Glenn had entered the craft, there was 2 more delays as first a guidance component was replaced and then a bolt to seal the capsule door securely.
The final words spoken before ignition were “Godspeed, John Glenn.” They were said by fellow astronaut John Carpenter as he anxiously watching the operation from mission control. But due to communications malfunctions, John Glenn never heard him.
Moments later, the rocket engines ignited. The launch went almost perfectly, and after less than 5 minutes of steadily increasing vibration the Friendship 7 reached an altitude of 162 miles above sea level, and a speed of 17,600 miles per hour.
The capsule made 3 complete orbits around the Earth. Glenn watched the sun both set and then rise again. He made observations of weather patterns and city lights he saw over Australia.
During this time he also experienced problems with the automatic attitude controls, as well as overheating in the cabin. In addition, Mission Control was concerned by warning sensors indicating the reentry heat shield wasn’t properly secured.
The capsule initiated reentry after only 3 orbits (6 were originally planned). Luckily the heat shield problem was only the result of a sensor error. Deceleration took place normally.
A slight delay in the deploy of the parachute provided one last moment of adrenaline before the Friendship 7 made a successful splashdown in the Atlantic Ocean.
The successful completion of the Mercury Atlas 6 mission would make John Glenn one of the most celebrated astronauts in U.S. history.
He was the first American to orbit the Earth, and his flight time surpassed the flight times of the 2 Russian cosmonauts who had proceeded him into orbit.
His successful mission was a monumental turning point in the evolving Space Race that began with the launch of the Sputnik satellite in October of 1957 and ended with Neil Armstrong, Buzz Aldrin, and Michael Collins completing a successful manned lunar landing in 1969.
He would go on to a third career in politics (after Marine and astronaut), winning a seat in the U.S. Senate, before finally riding to space again in 1998 aboard the Space Shuttle, at the age of 77.