by William H. Benson
July 25, 2019
Apollo 11’s Saturn V rocket lifted off from Kennedy Space Center’s Launch Complex 39A, on Merritt Island, Florida, on Wednesday, July 16, 1969, at 9:32 a.m. EDT. At that moment a clock began running. Hence, NASA officials set liftoff at zero hours Mission Time.
The Saturn V rocket contained almost a million gallons of kerosene, liquid oxygen, and liquid hydrogen. Michael Neufeld, a Smithsonian curator, said, “If the Saturn V had blown up on or near the launch pad, it would have had the force of a small nuclear weapon.”
After one complete orbit around Planet Earth, the three astronauts—Neil Armstrong, Edwin Aldrin, and Michael Collins—set a trajectory for a rendezvous with the Moon, 240,000 miles distant. Three days later, on Saturday, July 19, at 75:49 hours, the three entered into the first of numerous lunar orbits.
On Sunday, July 20, at 100:0:12 hours, the Command Space Module, CSM, and the Lunar Module, LEM, undocked from each other. Armstrong and Aldrin commanded the LEM, code-named “Eagle,” while Collins remained alone to pilot the CSM, code-named “Columbia.”
At 102:33:05 hours, when 50,000 +/- feet above the lunar surface, Armstrong and Aldrin flipped the switches that ignited the “powered descent engine.” Less than thirteen minutes later, at 102:45:39 hours, Armstrong landed the LEM on the Moon’s surface.
He reported, “Houston. Tranquility Base here. The Eagle has landed.”
NASA officials, historians, and journalists have dissected and rehashed those thirteen minutes often. The BBC even built a podcast around those tense, nail-biting, thirteen minutes.
First, the computer called out a series of “1202” computer malfunctions that alarmed Armstrong and Aldrin, plus Collins and Houston.
Later, NASA officials determined that they were asking the computer to complete too many tasks, that it felt overloaded, forced to drop certain tasks and stick with others. NASA officials chose to set aside the “1202” warnings, deal with them later, but let Armstrong land the Eagle, rather than abort.
Then, when Armstrong neared the Moon’s surface, he noticed that the computer wanted to land the Eagle in a crater filled with boulders, some as big as cars. Armstrong took over the landing, keeping the Eagle airborne long enough to pass over that crater until he saw a level plain, and there he landed.
One NASA official estimated that the Eagle had seventeen seconds of fuel remaining.
Six and a half hours later, at 109:24 hours, or 9:56 p.m. EDT, Neil Armstrong climbed down the ladder and planted a footprint onto the Moon’s surface. Buzz Aldrin followed at 109:43.
Together they planted the Stars and Stripes, set up a video camera, unveiled a plaque with their signatures engraved, collected dirt samples, snapped photos, heard President Nixon offer his congratulations from the Oval Office, and ambled about the Moon.
Buzz Aldrin looked about him, and called the scene, “Magnificent Desolation.”
After two hours outside, at 111:37, the two were back inside the Eagle. There they spent the night. Altogether, the two astronauts spent 21 hours and 36 minutes on the Moon’s surface.
The next day, July 21, at 12:54 p.m. EDT, or at 124:22 hours, the two flipped switches to ignite the Lunar module’s liftoff from the Moon’s surface. The rocket scientists had not built redundant machinery for a liftoff. If Armstrong and Aldrin were to leave the Moon, and return to Earth, that single liftoff system had to work, and it did. One newspaper though had a headline prepared if it failed, “Marooned.”
At 128:03 hours, three hours and forty-one minutes after liftoff, Armstrong and Aldrin docked their module with Columbia. They then joined Michael Collins inside the Command Module.
Three days later, on July 24, at 195:07 hours, the Command Module entered the Earth’s orbit, and at 195:18, it splashed down in the Pacific Ocean, some 800 miles southwest of Hawaii, some 12 miles from the USS Hornet.
After 8 days, 3 hours, 18 minutes, and 35 seconds, the three called their mission completed.
A helicopter carried the three to a quarantine trailer, where they remained until August 10. NASA officials feared that the astronauts would bring back a germ that would unleash an epidemic on Earth.
Soon, they were reunited with their families, and a New York City ticker tape parade awaited them.
Fifty years have passed since those moments in 1969, but the three astronauts’ story and adventure, their unimaginable achievement, continues to astonish and surprise everyone. They expected their mission to succeed, and it did.