By the summer of 1969, almost every element of the Apollo program had been tested and proven. The massive Saturn V rocket – the most powerful machine ever built and the first launch vehicle developed strictly for space applications – had shown it could reliably lift the Apollo modules and astronauts together beyond the Earth’s orbit. The command/service module (CSM) and lunar module (LM) could launch together, dock, and separate, and the LM could fly on its own. Russian and U.S. unmanned probes had performed soft landings on the Moon, dispelling fears that spacecraft would simply sink into the powdery lunar surface. In December of 1968, during the Apollo 8 mission, the power bottled in the Saturn V’s three stages sent U.S. astronauts Frank Borman, James Lovell, and William Anders into orbit around the Moon and back, a total distance of a little under a half million miles.

There was, really, only one question left to answer, and it was embedded in Apollo 11’s pithy prime mission objective: “Perform a manned lunar landing and return.”

Could a man land on the Moon? Even in the Information Age, it’s difficult to grasp the technological burst – still unequaled today – that approached its historic climax in the summer of 1969. A little more than eight years earlier, Yuri Gagarin and Alan Shepard had become the first men in space; now astronauts were preparing to set foot on another world. Many experts continued to fear that the LM – much heavier than its unmanned predecessors – would sink into the lunar surface, fatally stranding the astronauts.

Judging from the icy cool of his decision-making in the Gemini 8 mission – and later in Apollo 11 – astronaut Neil Armstrong probably wasn’t fanciful enough to imagine he’d be mired in a lunar bog. But he did, reportedly – along with many NASA officials – fix the chances of a successful lunar landing attempt at about 50/50.  There were simply too many unknowns. 

To offset these unknowns, the Apollo 11 astronauts – Armstrong, the commander; Buzz Aldrin, the lunar module pilot; and Michael Collins, the command module pilot – trained fourteen hours a day, six days a week, from January to July 1969. About a third of Armstrong and Aldrin’s training time was spent inside the lunar module simulator and they began consistently demonstrating successful landings some time in late June, about two or three weeks before launch. To be fair, these simulations were led by ground crews who threw every imaginable problem at the two, who by July had probably begun to wonder when the bells, sirens, and warning lights of the simulator were going to burn themselves out. By July, NASA and its astronauts were as ready as they were ever going to be.

 

Outward Bound 

The American public, on the other hand, had some catching up to do. Since the onset of the “space race,” the visionary idealist who had launched it, John F. Kennedy, had been assassinated. The nation had become increasingly entangled in an unpopular war in Vietnam and in rancorous, sometimes violent, political debates at home about civil rights, poverty, and the competence of its leaders. Many Americans, by the end of the decade, seemed to have lost interest in the space program, or to believe it was a waste of the nation’s resources.

Most accounts of the time just prior to the Apollo 11 launch, however, portray a reawakening of the American spirit – and in the spirits of millions of people around the world – during the spring and summer of 1969. Launched as a competition to prove the superiority of one political system over another, the goal of the Moon had taken on much more significance in the intervening years and as the launch date neared there was, it seemed, a mounting public appreciation of the almost metaphysical importance of the approaching moment. 

On the morning of July 16, as the Apollo 11 astronauts – who had awakened early that morning, even by astronaut standards – sat atop the 363-foot Saturn V at Kennedy Space Center’s Launch Complex 39A, a million eyewitnesses packed themselves into the surrounding sandy flats and shorelines, waiting along with a worldwide television audience. Three and a half miles away, seated in grandstands, were half the members of Congress and more than 3,000 journalists from 56 different nations. At 9:32 a.m. Eastern Daylight Time, the rocket blasted the Apollo 11 crew into the sky. 

Threading the sky at more than 6,300 miles per hour, Apollo 11 jettisoned its first two rocket stages and entered a 103-mile high Earth orbit, during which flight and ground crews checked the spacecraft’s functions.  At 12:22 p.m., Apollo 11 fired its third-stage engine to launch it out of Earth orbit and into a lunar trajectory. A little more than 20 minutes later, the lunar module Eagle was unpacked from its compartment atop the launch rockets, and the CSM, Columbia, turned around and docked head-to-head with the LM. The crew passed the next three days traveling at a speed of nearly 13,000 feet per second, taking time from their daily routines to send two extended telecasts back to Earth.  

The crew approached the Moon on the morning of July 19, a sight Michael Collins later recalled in his memoir, Carrying the Fire: “The Moon I have known all my life, that two-dimensional small yellow disk in the sky, has gone away somewhere, to be replaced by the most awesome sphere I have ever seen.”  At about half-past 1:00 p.m. Eastern Time, the astronauts fired Columbia’s main rocket to slow the vehicle for entry into lunar orbit. It had been another epic Apollo journey, only the third spaceflight to the Moon – but until now, everything done by Armstrong, Aldrin, and Collins had been done before.  

 

Landing the Eagle 

On the fourth day of Apollo 11 – July 20, 1969 – its crew began to prepare for the mission’s unproven tasks. Aldrin crawled through the hatchway linking Columbia and Eagle and powered up the lunar module, to be joined about an hour later by Armstrong. Together, they rechecked the systems and deployed the LM’s spidery legs. On the far side of the Moon, at about 1:46 p.m., Collins pressed the switch that separated Columbia from the lander, kissing it off with the push of gentle springs.  “See you later,” he said. Armstrong and Aldrin were on their own now, rocketing over the lunar surface face down, feet forward. Armstrong fired the LM’s main engine in counterthrust, to slow the craft’s horizontal velocity, while Collins resumed his orbit.

As well-prepared as they considered themselves and the astronauts to be, NASA officials viewed the first lunar landing with concern. Gene Kranz, the legendary NASA Flight Director, recalled in a 1999 interview conducted for the NOVA television special, To the Moon: “Going through my mind was a very simple equation: Today we are either going to land, we are going to abort, or we are going to crash.”

As if on cue, the Eagle’s descent to the lunar surface promptly confronted Apollo 11 with its two most serious tests – either of which had the potential to kill the mission. At an altitude of just over 7,000 feet, about five miles from the landing site, the LM pitched over to assume its vertical landing posture, the ghostly lunar surface visible through the downward-angled windows. It descended about another 1000 feet and then the guidance computer sounded an alarm. The light that came on in the LM was coded 1202, an “executive overflow” alarm, which meant the computer was having trouble completing its work in the cycling time available.  

Almost nobody knew what a 1202 was and in the first row of consoles at the Mission Control Center – “the Trench” – it fell to 26-year-old Guidance Officer (GUIDO) Steve Bales to make the split second decision – Go or No Go. 

“GUIDO?” Kranz shouted, seeking an answer. The Eagle was burning up its descent fuel. Luckily, Bales was aided by 24-year-old Jack Garman, an expert in the guidance computer software, who knew immediately that the computer would complete its work as long as the alarm didn’t sound too frequently – a signal that it was overwhelmed. “It’s okay,” he assured Bales, who shouted “Go!” to the Capsule Communicator (CapCom), astronaut Charlie Duke.  

“We are Go on that alarm, Eagle,” Duke said.   

A few months earlier, Garman had suggested to the simulation supervisor, Dick Koos, that flight controllers should be tested on their reactions to computer error codes. Koos did, throwing a 1202 alarm at Kranz and his flight controllers on the last day of simulations, two weeks before the launch date. Bales, incorrectly, had called an abort – and, Kranz wrote later, “I was ready to kill Koos.” At Kranz’s insistence, Bales and the other controllers then wrote down every possible computer error code and the correct response to each – a list Garman had beneath his console glass during Apollo 11.

Meanwhile, as Armstrong eased the LM down toward the Moon, he and Aldrin could see that the chosen landing area, the vast Mare Tranquillitatis (Sea of Tranquility) – which had been selected because of its relative smoothness – wasn’t as smooth as advertised. Worse, the Eagle had come in slightly faster than anticipated, overshooting the target site and sailing over a crater strewn with boulders that would wreck the LM. Armstrong swiftly overrode the computer and assumed manual control. There was no time to discuss the decision with Mission Control in Houston; there was precious little reserve fuel for the descent stage and Armstrong would need every available second of it.

The Eagle diverged from the programmed path, coasting over the boulder field, searching for a clear landing spot as the fuel level dropped nearer to zero. In Houston, Charlie Duke called out the remaining fuel: “Sixty seconds.” Mission Control watched in silence, stunned at the telemetry data that told them the LM had not landed yet, but was throttling rapidly over the surface. Armstrong, who had crashed the LM many times during simulation, was, despite his outward calm, feeling the stress of the moment; his heart rate had climbed from a normal rate of 77 to 156. “Thirty seconds,” Duke radioed.  

Finally, Armstrong saw what he needed – a clear spot just beyond a small crater.  He brought the Eagle down slowly, kicking up sheets of gray dust that enveloped the LM. The lander’s downward-pointing feelers touched the surface of the Moon, tripping the circuit that illuminated the blue indicator light in the cockpit. “Contact light,” Aldrin called. Armstrong cut the engine, and the four footpads came down on the lunar soil. 

“We copy you down, Eagle,” said Charlie Duke.  

His heart rate beginning to slow a bit, Armstrong’s voice was calm and clear: “Houston, Tranquility Base here. The Eagle has landed.”

 

The Moon Walk 

After the tense moments spent waiting for the Eagle to land, Kranz recalled, many in Mission Control simply burst into tears after the LM landed and he himself admitted to having some trouble getting out the words that would begin the next sequence for the astronauts and Mission Control: the Stay or No Stay decision. Armstrong and Aldrin, once down, immediately prepared the ship for the contingency of an emergency launch.  

There was one last remaining unknown for Armstrong and Aldrin: whether they could actually walk on the surface of the Moon. It was beginning to seem more likely, but the Moon environment – which fluctuated about 500 degrees Fahrenheit in temperature, between the fatal extremes of about 243 degrees Fahrenheit at lunar “noon” to 279 degrees Fahrenheit below zero at “night” – was more forbidding than an Earth-orbit EVA (Extra-vehicular activity). Apollo 11 had been planned to land during lunar morning, which would make the outside temperature a more hospitable 40 or 50 degrees. The Moon spacesuit, also, had been reinforced with several aluminized layers to guard against not only the temperature extremes, but also the possibility of a tear – which would promptly prove fatal, causing an explosive decompression that would vent the astronaut’s oxygen into space.  

Six hours after landing, Aldrin and Armstrong had bled the Eagle’s cabin of air and were sealed in their suits, their enormous backpacks supplying them with cooled oxygen. At about 10:56 p.m. Eastern time, Armstrong stepped outside, the lunar sky around him darker than the blackest night on Earth, and descended the Eagle’s ten-foot ladder, on his way down, activating a television camera that had been installed specifically to capture the moment. His approach demonstrated the extreme caution with which the moment had been planned: first, he paused at the bottom rung to observe the lunar surface. “The LM footpads are only depressed in the surface about one or two inches,” he said.  “The surface appears to be very, very fine-grained, as you get close to it. It’s almost like a powder.” He dropped first onto one of the Eagle’s footpads, surveying the surface. And then, finally, it was time for the first person in history to set foot on something that did not exist on Earth.  

“I’m going to step off the LM now,” Armstrong said. He planted his foot on the surface – which was firm beneath the thin layer of moondust. With more than a billion people listening in, he said: “That’s one small step for a man, one giant leap for mankind.”  

He was joined about 19 minutes later by Aldrin, who described the lunar landscape as “magnificent desolation.” The two astronauts took several exploratory strides, bouncing over the surface of the Moon, whose gravitational pull, one-sixth that of the Earth, transformed the combined 360 pounds of astronaut, suit, and backpack to a mere 60 pounds. “Isn’t this fun?” said Armstrong at one point.

“I was struck,” Aldrin recalled later, “by the contrast between the starkness of the shadows and the desert-like barrenness of the rest of the surface. It ranged from dusty gray to light tan and was unchanging except for one startling sight: our LM sitting there with its black, silver, and bright yellow-orange thermal coating shining brightly in the otherwise colorless landscape.”

About two and a half hours were allocated for the astronauts’ inaugural Moon excursion, and there were many tasks to accomplish, including the planting of an American flag, photographing, collecting lunar soil and rock samples, and setting up three experiments: a seismic experiments package to measure moonquakes and meteor impacts; a laser ranging retro-reflector that would allow scientists to precisely measure Earth-Moon distances; and a solar wind experiment – basically, a sheet of foil for collecting solar wind particles, which could not be collected on Earth due to the deflection from its magnetic field. Armstrong and Aldrin also answered a congratulatory phone call from President Richard Nixon.

As they worked, Collins continued his silent vigil, spending 48 minutes of each orbit behind the dark side of the Moon, out of radio contact – a time during which, he recalled in his memoir, he felt “not fear . . . or loneliness, but . . . awareness, anticipation, satisfaction, confidence, almost exaltation.”  

After resting in the LM that night, Armstrong and Aldrin, using the Eagle’s descent stage as a launch pad, blasted off from the lunar surface at 1:54 p.m. They took with them soil samples, solar wind particles, film, and some mementos to be returned to Earth. At 5:35 p.m., while circling the back side of the Moon, Eagle and Columbia redocked, and Aldrin and Armstrong joined Collins for the ride home.

On the Moon, Apollo 11 had left behind a number of items, including the flag and equipment they didn’t need any more. They also left medals and shoulder patches in honor of the five astronauts who lost their lives in the race to the Moon: Yuri Gagarin, Vladimir Komarov, Virgil Grissom, Roger Chaffee, and Edward White. Gagarin and Komarov’s medals had been given to Frank Borman, the Apollo 8 commander, by the Soviet astronauts’ widows during a previous visit to Moscow.

The largest object left behind, of course, was the lower half of the Eagle, which, affixed to one of its legs, bore a plaque inscribed with both hemispheres of the Earth, the signatures of the three astronauts and President Nixon, and the inscription: 

HERE MEN FROM THE PLANET EARTH

FIRST SET FOOT UPON THE MOON

JULY 1969, A.D.

WE CAME IN PEACE FOR ALL MANKIND

Apollo 11’s Legacy

The next three days were, for the astronauts, anticlimactic, even boring.  About halfway home, they transmitted the final color television transmission from the cabin of Columbia, during which each of the crewmen reflected on their experiences. Each of them took the opportunity to point out that the Moon mission was an achievement for which thousands, even millions, deserved credit.  Said Armstrong: 

The responsibility for this flight lies first with history and with the giants of science who have preceded this effort; next with the American people, who have, through their will, indicated their desire; next with four administrations and their Congresses, for implementing that will; and then, with the agency and industry teams that built our spacecraft, the Saturn, the Columbia, the Eagle, and the little EMU, the spacesuit and backpack that was our small spacecraft out on the lunar surface. We would like to give special thanks to all those Americans who built the spacecraft; who did the construction, design, the tests, and put their hearts and all their abilities into those craft. To those people tonight, we give a special thank you, and to all the other people that are listening and watching tonight, God bless you. Good night from Apollo 11.

The trip back to Earth was so uneventful that only one of four planned course corrections was required. Columbia entered the atmosphere of the Earth at 12:35 p.m. on July 25, splashing down in the Pacific Ocean. After arriving on the flight deck of the aircraft carrier USS Hornet, Aldrin, Armstrong, and Collins were rushed into a quarantine chamber designed to protect the rest of the world from the remote possibility of contamination from “Moon germs” or lunar microorganisms. Of all the otherworldly images of the Apollo 11 mission, one of the strangest is the photograph of the three astronauts, sealed inside their quarantine chamber, being greeted by President Nixon, who was aboard the Hornet for the occasion. 

It is no exaggeration to say that, upon the return of the Apollo 11 astronauts, the entire world rejoiced. Even the Soviet Union, mirroring the astronaut’s goodwill gesture of enshrining Gagarin and Komarov on the Moon, offered its heartfelt congratulations.  

In fact, political leaders the world over viewed Apollo 11 as possibly the most historic success ever achieved by humankind, and it became a touchstone for optimists the world over: What couldn’t we do, if we could do this? Golda Meir, Israel’s new Prime Minister, publicly expressed the wish that Apollo 11’s achievement of the impossible could pave the way to the universal peace predicted by the prophets of Israel.

Today many people, jaded by the intervening years of conflict and bloodshed around the world, would probably regard such a sentiment as naïve. But many thought the same thing of President Kennedy on May 25, 1961, when he challenged Americans to find a way to the Moon. It is often pointed out – and it seems worth remembering – that Apollo 11, inspired in the 1950s by mortal fear of the Cold War enemy, resulted in perhaps the most powerful expression of hope ever shared by the people of the world. 

This story originally appeared in Apollo 11: 50th Anniversary of the Moon Landing.