On July 16, 1969, Apollo 11 astronauts Neil Armstrong, Buzz Aldrin, and Michael Collins launched from Florida’s Kennedy Space Center with the goal of becoming the first people in history to walk on the Moon. Four days later, on July 20, 1969, the manned mission achieved that historic goal when Neil Armstrong took his famous “one small step” onto the lunar surface. But getting there was hardly smooth sailing.

1. The original goal of the Apollo program was to send a crew into the Moon’s orbit, but John f. Kennedy wanted more.

When the Apollo program was announced in 1960, the original plan was to send a small crew into the Moon's orbit, not to its surface. President Kennedy, of course, made his famous speech in 1961, declaring his and the United States's commitment to landing a man on the Moon before the end of the decade.

2. Apollo 11’s goal was simply to arrive on the Moon, then return to Earth.

When it came to the primary objective of the Apollo 11 mission, NASA kept it simple: "Perform a manned lunar landing and return."

3. The Apollo 11 astronauts were oddly calm during liftoff.

The average resting heart rate of an adult human is somewhere between 60 and 100 beats per minute (bpm), depending on the individual’s age, size, heart conditions, and other factors. Throw a little excitement into the mix and one’s heart is likely to beat much faster. Yet the Apollo 11 astronauts, whose heart rates were monitored throughout the expedition, remained surprisingly normal. At liftoff, Armstrong was the most excited of the bunch with a rate of 110 bpm. Collins, meanwhile, was clocked at 99, while a clearly calm Aldrin logged a rate of just 88 bpm.

4. The most important Apollo 11 spectators were seated miles from the launch pad.

While millions of people kept track of Apollo’s movements on television, space program enthusiasts also traveled to Florida to watch the guys launch into space with their own two eyes. It was the perfect opportunity for NASA to honor some of the organization’s biggest supporters and VIPs with a prime seat for watching it all go down. But even then, those individuals were seated 3.5 miles from the launchpad—in the event that the rocket exploded upon takeoff.

5. Richard Nixon had a speech prepared in case the Apollo 11 astronauts never came home.

As with many historic undertakings, President Nixon had to prepare for the possibility that a tragedy might occur during the Apollo 11 mission. So his speechwriter, William Safire, wrote two different speeches: one to celebrate the mission’s victory, another titled “In the Event of Moon Disaster.” It stated:

"Fate has ordained that the men who went to the Moon to explore in peace will stay on the Moon to rest in peace.
These brave men, Neil Armstrong and Edwin Aldrin, know that there is no hope for their recovery. But they also know that there is hope for mankind in their sacrifice."

You can read the full text online [PDF].

6. Your toaster is more advanced than Apollo 11’s command module computer.

Though the Apollo Guidance Computer (ACG) was cutting-edge technology for its time, when compared to the computer-based items we use every day, they were pretty basic. reported that these “ingenious computer systems” were no more powerful than a pocket calculator and that the ACG was “more basic than the electronics in modern toasters that have computer controlled stop/start/defrost buttons."

7. The Apollo 11 astronauts consumed a lot of fizzy water.

Due to a problem with the spacecraft’s hydrogen-gas filters, the men’s drinking water was always a bit bubbly. “The drinking water is laced with hydrogen bubbles (a consequence of fuel-cell technology which demonstrates that H2 and O join imperfectly to form H2O)," Michael Collins wrote in Carrying the Fire: An Astronaut's Journeys, his 1974 memoir.

8. All those bubbles meant that there was a lot of farting.

As if being in tight quarters for several days didn’t already present enough challenges, all those fizzy drinks led to some serious flatulence. “These bubbles produced gross flatulence in the lower bowel, resulting in a not-so-subtle and pervasive aroma which reminds me of a mixture of wet dog and marsh gas,” Collins wrote.

9. Normal bodily functions weren’t a thing that NASA had adequately planned for with Apollo 11.

Speaking of bodily functions: NASA hadn’t fully worked out all the challenges the astronauts might face when attempting to go to the bathroom in a zero-gravity situation. One Apollo 11 astronaut spent the entire trip loading up on anti-diarrhea medication so that he could forgo having to deal with that situation altogether (though the identity of that astronaut has never been made public).

10. Buzz Aldrin’s mom had a prophetic last name.

Before Buzz Aldrin’s mom, Marion, married Edwin Eugene Aldrin Sr., she was known as Marion Moon. When asked by The New York Times to confirm the veracity of that fun coincidence, Aldrin responded with an emphatic: “Yes. I didn’t feel NASA needed to know that. Somebody would think I was trying to get favored treatment because my ancestors had the name Moon. And that’s a joke.”

11. Michael Collins designed the Apollo 11 insignia.

In 1965, Gemini V became the first NASA crew to have a dedicated insignia, which was designed by pilot Pete Conrad and command pilot Gordon Cooper. This tradition of a crew wearing patches designed by its own members has continued over the years, with the Apollo 11 crew following suit. Ultimately, they decided to make the concept a representation of the larger goals of NASA—and America—at the time.

"We wanted to keep our three names off it because we wanted the design to be representative of everyone who had worked toward a lunar landing, and there were thousands who could take a proprietary interest in it, yet who would never see their names woven into the fabric of a patch,” Collins said. “Further, we wanted the design to be symbolic rather than explicit."

12. Neil Armstrong wasn’t convinced that they’d be able to land the Lunar Module.

In 2012, in a rare interview, Armstrong admitted that while he was confident he and his fellow crew members would make it back to Earth, he was less convinced that the crew would succeed in landing their lunar module, known as Eagle.

"A month before the launch of Apollo 11, we decided we were confident enough we could try and attempt on a descent to the surface," Armstrong said. “I thought we had a 90 percent chance of getting back safely to Earth on that flight but only a 50-50 chance of making a landing on that first attempt. There are so many unknowns on that descent from lunar orbit down to the surface that had not been demonstrated yet by testing and there was a big chance that there was something in there we didn't understand properly and we had to abort and come back to Earth without landing."

13. The woman who coined the phrase software engineering is partly to thank for sending Apollo 11 to the Moon.

Getting to the Moon requires some serious software innovation, especially in the 1960s. Margaret Hamilton led the team that wrote every line of code for the Apollo Guidance Computer. Hamilton—a pioneer who coined the term software engineering—is probably most recognizable for the famous photo of her and the stack of printed-out code standing as tall as she is. She was just 33 years old when that code sent the Apollo 11 mission to the Moon.

14. The source code that took Apollo 11 to the Moon was full of jokes and political references.

Computer programmers aren't generally known for their senses of humor, but a piece of space history—discovered in 2016—suggests that maybe they should be. Former NASA intern Chris Garry uploaded the Apollo 11 flight source code to GitHub, revealing a legendary piece of flight software that was full of jokes and topical 1960s references.

Paired with the code that helped NASA astronauts navigate the Moon landing are file names like "BURN_BABY_BURN," which, as ABC News reported, is actually a reference to DJ Magnificent Montague and the Black Power movement. Other comments include "HELLO THERE," "GOODBYE. COME AGAIN SOON," and file names like "PINBALL_GAME_BUTTONS_AND_LIGHTS."

15. Pieces of the Wright Brothers’ first aircraft were onboard Apollo 11.

In 1969, the Air Force contacted Armstrong to see if he’d be willing to take pieces of the Wright Brothers’ first aircraft to take flight to the Moon with him. As a thank you, Armstrong would be allowed to keep half of the pieces. Armstrong, an avid flier, was enthusiastic.

"It was important to take the genesis of flight with him," Mark Armstrong, Neil’s son, said earlier this year. "First and foremost, he was an engineer and someone who wanted to make aircraft better. That was his boyhood goal, to be an aircraft designer.”

16. When asked what he wanted to take with him to the Moon, Armstrong’s answer was somewhat prophetic.

On July 5, 1969, the Apollo 11 astronauts did a roundtable interview with members of the press. When asked whether he’d be taking any personal mementos to the Moon with him, Armstrong responded: “If I had a choice, I would take more fuel."

17. When Apollo 11 landed, they were really low on fuel.

Why was Armstrong’s aforementioned response so prophetic? When Apollo 11 finally did land, their fuel supply was extremely low. The alarm had already sounded that the men had 60 seconds left to land or abort, then the 30-second alarm sounded. "When it got down to 30 seconds, we were about 10 feet or less" from the surface, Aldrin said. "I could sneak a look out, because at that point, I don't think Neil cared what the numbers were. He was looking at the outside. I could see a shadow of the sun being behind us." Seconds later, Armstrong confirmed to Houston that, "the Eagle has landed."

18. Eagle’s overworked computer system had Apollo 11 landing in a boulder-filled crater.

Eagle's computer was really put to the test during the mission’s landing—so much so that it was attempting to land the module in a crater full of boulders. "Those slopes are steep, the rocks are very large—the size of automobiles," Armstrong said. In order to avoid that potential disaster, Armstrong took manual control of the lunar module and attempted to find a safer place for them to land.

19. Apollo 11 landed in the wrong place.

Needless to say, Apollo 11 didn’t touch down at its intended landing site. Thanks to Armstrong’s quick thinking, they were able to successfully land—albeit 4 miles from where they were supposed to. “I took it over manually and flew it like a helicopter out to the west direction, took it to a smoother area without so many rocks, and found a level area and was able to get it down there before we ran out of fuel,” Armstrong said.

20. Armstrong’s "small step" was more of a "giant leap."

Because Eagle had to reconfigure its landing site, Armstrong’s landing was a very gentle one—so gentle that the module’s pads and legs didn’t collapse as they were supposed to. Which meant that the bottom rung of Eagle’s ladder was about 3.5 feet above ground. In order to get to the surface of the Moon for that official step, he first had to hop off the ladder, then back up to it (to make sure he could reach it again). Then came that whole “one small step” business.

21. Armstrong’s first steps took place late at night.

22. A lot of people watched the Apollo 11 Moon landing happen.

It may have been past a lot of kids’ bedtimes, but an estimated 600 million people around the world watched Apollo 11 land on live television.

23. Even Disneyland guests took a break from Mickey and Minnie to watch the Moon landing.

24. Armstrong swore that his “one small step” line was misheard back on Earth.

People back on Earth who watched Armstrong’s first steps onto the lunar surface could have sworn that they heard him say, “That's one small step for man, one giant leap for mankind,” but Armstrong repeatedly stated that this was incorrect. And what he really said was, “That's one small step for a man, one giant leap for mankind.”

"It's just that people just didn't hear [the 'a']," Armstrong told the press once he was back on Earth. In 2006, a computer programmer used a piece of software to analyze Armstrong’s words and found that the “a” was indeed there (it was likely not heard because of radio static).

25. Armstrong tried to not be too awed by his surroundings.

Ever the professional, Armstrong did his best to ignore the fact that he was standing on the Moon so that he and Aldrin could get their work done. According to The Guardian, "Armstrong said there was too much work to do to spend too long meditating or reflecting on where he was."

26. Armstrong may have been the first man to walk on the Moon, but Buzz Aldrin was the first man to pee on the Moon.

"It's lonely as hell out there," Aldrin told a crowd of people at Washington, D.C.'s Newseum in 2009. "I peed in my pants."

27. No one back at NASA HQ knew what "Tranquility Base" meant.

In all of the meticulous pre-mission planning, two words never came up: “Tranquility base.” Which made Armstrong’s announcement that, “Houston. Tranquility Base here. The Eagle has landed,” kind of confusing. Fortunately, the folks back in Houston just rolled with it.

28. At the same time Armstrong and Aldrin were completing their moonwalk, a soviet spacecraft accidentally crashed into the Moon.

At the same time that Armstrong and Aldrin were wrapping up their work on the lunar surface, Luna 15—an unmanned Soviet spacecraft—accidentally crashed into the Moon approximately 530 miles from the Sea of Tranquility.

29. Collins was terrified that something would go wrong and he’d have to return to Earth alone.

In his memoir, Michael Collins wrote about how dangerous the Apollo 11 mission was and how terrified he was that something would go wrong. “If they fail to rise from the surface, or crash back into it, I am not going to commit suicide,” Collins wrote about the moment when he watched his fellow astronauts attempt their return home. “I am coming home, forthwith, but I will be a marked man for life, and I know it.”

30. Some Apollo 8 legal problems caused a last-minute change of plans.

When Apollo 8 circled the Moon on December 24, 1968, they were asked to do “something appropriate” to mark the occasion for the millions of people who were spending their Christmas Eve listening to them back on Earth. They decided to read a verse from Genesis, which ended up enraging noted atheist Madalyn Murray O’Hair to the point that she sued the space organization, claiming that reading had violated her First Amendment rights. The case was eventually thrown out, but NASA didn’t want to chance having to deal with a similar situation with Apollo 11. Buzz Aldrin had planned to read a communion passage, but was asked to scrap it at the last minute.

31. A communion wafer was the first item eaten on the Moon.

Though Aldrin wasn’t able to share his communion passage with those back on Earth, he did take a few moments to observe the sacrament privately shortly after landing on the Moon. "I ate the tiny host and swallowed the wine,” Aldrin said. “I gave thanks for the intelligence and spirit that had brought two young pilots to the Sea of Tranquility. It was interesting for me to think: The very first liquid ever poured on the moon, and the very first food eaten there, were the communion elements."

32. Armstrong and Aldrin had to be careful not to lock themselves out of the module.

If their heart rates were any indication, Armstrong and Aldrin were pretty calm, cool, and collected when they landed on the Moon. And it’s a good thing: Had they been overwhelmed by the cosmic wonder of it all, they could have easily locked themselves out of their lunar module, as Eagle’s door had no outer handle.

33. There was some confusion about where the Apollo 11 flag came from.

Before landing on the Moon, there was much discussion as to how appropriate planting any single country's flag on its surface would be. Ultimately it was decided that the men would plant an American flag and leave a plaque emphasizing that they “came in peace for all mankind.”

Of course, then the big question became: Where did that American flag come from? NASA tried their best to dodge the question, explaining that they had purchased flags from several different manufacturers. However, it turned out that all of the flags came from Sears, but the space organization didn’t “want another Tang” on their hands. In other words: They didn’t want Sears to turn the Moon landing into an advertising campaign for the company.

34. Planting the American flag wasn’t as seamless a task as it may have seemed.

Though studies conducted before Apollo 11’s mission had concluded that the Moon’s surface would be soft, Armstrong and Aldrin quickly learned that wasn’t the case. The surface was made of hard rock, with a layer of dust on top of it, which made planting the American flag one of their toughest jobs.

35. That flag didn’t stand for very long.

While the photos of Armstrong and Aldrin standing next to the planted American flag are famous around the world, that flag didn’t stay standing very long, Thanks to the power produced by Eagle’s thrusters when the two launched back into lunar orbit, the flag quickly toppled over.

36. The flag most likely disintegrated.

As for what happened to that flag once it fell over? It likely turned to ashes. “The flag is probably gone,” Tony Reichhardt wrote for Air & Space Magazine. “Buzz Aldrin saw it knocked over by the rocket blast as he and Neil Armstrong left the Moon … Lying there in the lunar dust, unprotected from the sun’s harsh ultraviolet rays, the flag’s red and blue would have bleached white in no time. Over the years, the nylon would have turned brittle and disintegrated.”

37. The astronauts left a lot of stuff behind.

Armstrong and Aldrin left more than just that flag behind: Among the other meaningful mementos that didn’t make the trip back to Earth were messages from 73 world leaders, a gold pin in the shape of an olive branch (meant to symbolize peace), and a patch from the Apollo 1 mission (which never launched because three of its astronauts were killed during a training exercise).

38. Apollo 11's return to Earth is largely due to a felt-tipped pen.

When Eagle landed on the Moon’s surface, the circuit breaker’s switch—which was essential for their return to Earth—accidentally broke off. Aldrin wrote about how some quick-thinking helped solve the problem in his 2009 memoir, Magnificent Desolation: The Long Journey Home From the Moon:

"Since it was electrical, I decided not to put my finger in, or use anything that had metal on the end. I had a felt-tipped pen in the shoulder pocket of my suit that might do the job. After moving the countdown procedure up by a couple of hours in case it didn't work, I inserted the pen into the small opening where the circuit breaker switch should have been, and pushed it in; sure enough, the circuit breaker held. We were going to get off the Moon, after all."

39. Aldrin kept that pen as a memento.

In addition to that pen, Aldrin also kept the broken circuit breaker switch. Before they took off, all three of the Apollo 11 astronauts were issued their own "Rocket" felt-tipped pen today, Collins’s can be seen at the Smithsonian National Air and Space Museum.

40. The rocks they brought back were billions of years old.

While the press seemed most interested in what the Apollo 11 astronauts were planning to take with them to the Moon, what they brought back was even more amazing. Some of the rocks they brought home were estimated to be 3.7 billion years old.

41. Armstrong’s bag of Moon dust was accidentally sold for $995.

While surveying the surface of the Moon, Armstrong collected a bag of dust for NASA scientists to study and analyze. In 2015, that bag of Moon dust was purchased from a government auction site for $995 by Chicagoan Nancy Lee Carlson. When Carlson sent the bag to NASA to confirm the authenticity of what was inside it, NASA claimed the bag was their property and refused to send it back. So Carlson took the agency to court, where a judge ruled in her favor. In 2017, Carlson sold the bag for $1.8 million via Sotheby’s.

42. The Moon apparently has a very distinct smell.

"It smelled, to me, like wet ashes in a fireplace,” Armstrong said of the Moon’s smell.

To Aldrin’s nose, however, it was more of “a pungent metallic smell, something like gunpowder, or the smell in the air after a firecracker has gone off."

43. Buzz Aldrin had to fill out an expense report for his trip to the Moon.

Bureaucracy doesn’t stop for world-changing events. Though he made history by becoming the second person to walk on the Moon, Aldrin—like so many other office drones before and after him—was forced to be subjected to the mundane indignities of filling out his expense reports. The astronaut, who retired in 1971, requested reimbursement for $33.31 in travel expenses incurred while traveling to and from Cape Kennedy in Florida.

44. The astronauts had to fill out customs forms, too.

Just like any other traveler who left the United States, the Apollo 11 team had to fill out customs forms when they made their way back through Honolulu.

45. Armstrong, Aldrin, and Collins were quarantined for more than two weeks upon their return to Earth.

On July 24, the Apollo 11 crew reentered Earth's atmosphere and splashed down into the Pacific Ocean after more than a week in space. In order to ensure the men hadn’t brought back any sort of weird Moon diseases or other microbes, Armstrong, Aldrin, and Collins were quickly placed into a mobile quarantine unit, which was then transported to the NASA Lunar Receiving Laboratory at Houston's Johnson Space Center. They were released from quarantine on August 10, 1969.

46. Hundreds of autographed photos were the astronauts’ version of life insurance.

To make sure that their families were taken care of, financially, if they did not return from their mission, the Apollo 11 astronauts spent part of their pre-mission quarantine signing hundreds of autographs, which were to be auctioned off if and when needed. Fortunately, they were not.

47. Apollo 11 “life insurance autographs” still pop up at auctions from time to time.

Space historian Robert Pearlman told NPR that Apollo 11 insurance autographs began popping up at space memorabilia auctions in the 1990s, where they could fetch $30,000 apiece. When Armstrong, who did his best to stay out of the spotlight following Apollo 11, learned that people were profiting from his autographs, he stopped signing them altogether.

48. The Apollo 11 astronauts (mostly) laughed off the conspiracy theories.

Even 50 years later, there are still some people who believe that the Moon landing was a hoax. But the men who manned Apollo 11 had a sense of humor about it. “It would have been harder to fake it than to do it,” Armstrong once famously said. And on at least one occasion, Aldrin had a hard time laughing it off.

In 2001, Aldrin was approached by conspiracy theorist Bart Sibrel, who wanted the astronaut to put his hand on a Bible and swear to God that he had walked on the Moon. While Aldrin did his best to ignore Sibrel, the NASA legend didn't take too kindly to being called "a coward, and a liar, and a thief" by Sibrel. So he punched him in the face ...

49. no, The Apollo 11 astronauts did not have an alien encounter.

In 2018, UFO enthusiasts ran with an out-of-context quote Aldrin had given about an unidentified object the crew had seen outside the spacecraft's window. While many tabloids ran with the idea that Aldrin was saying the Apollo 11 crew had seen a UFO, Aldrin was quick to correct the record ... but it was too late to stop the conspiracy theories from developing. In a 2014 Reddit AMA, Aldrin tried to set the record straight yet again:

"On Apollo 11 [en] route to the Moon, I observed a light out the window that appeared to be moving alongside us. There were many explanations of what that could be, other than another spacecraft from another country or another world—it was either the rocket we had separated from, or the 4 panels that moved away when we extracted the lander from the rocket and we were nose to nose with the two spacecraft. So in the close vicinity, moving away, were 4 panels. And i feel absolutely convinced that we were looking at the sun reflected off of one of these panels. Which one? I don't know. So technically, the definition could be 'unidentified.'
... [W]hen we returned, we debriefed and explained exactly what we had observed. And I felt that this had been distributed to the outside world, the outside audience, and apparently it wasn't, and so many years later, I had the time in an interview to disclose these observations, on another country's television network. And the UFO people in the United States were very very angry with me, that I had not given them the information. It was not an alien."

50. The first men to walk on the Moon had a lot of help.

In total, it’s estimated that it took approximately 400,000 scientists, engineers, and technicians to make Apollo 11’s mission a success.

This article was originally published on www.mentalfloss.com as 50 Facts About the Apollo 11 Moon Landing.