This week marks the fiftieth anniversary of the Apollo 11 mission, when astronauts Neil Armstrong, Buzz Aldrin, and Michael Collins became the first people in history to land on the Moon. Here are five facts you should know about the most famous manned space mission.

1. The Apollo 11 mission was carried out by three mander Neil Armstrong, lunar module pilot Buzz Aldrin, mand module pilot Mike Collins. But the team that took them to the moon included more than 400,000 scientists, engineers and technicians, and workers from across the United States. Many of the people on the project were also relatively young. The average age of the engineers inside Mission Control when the Apollo 11 capsule returned on July 24, 1969 was 28.

2. puters on the Apollo spacecraft were plex than a basic calculator. According to Computer Weekly, astronauts entered mands using verb-and-noun instructions: a verb to tell puter to do a specific action, and a corresponding noun on which to do it [i.e. “aim telescope”]. To do that, it only needed 64 kilobytes of memory and operated at 0.043MHz. Today, a USB memory stick today is more powerful than the Apollo Guidance Computer.

3. Armstrong wasn’t convinced the team would be able to land their lunar module, and put the odd of success at only 50-50. “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 e back to Earth without landing,” said Armstrong. His concerns were not unwarranted since mishaps were likely. While Armstrong and Aldrin were concluding the first moonwalk, the Soviets Luna 15 probe crashed into the Moon about 530 miles from the Apollo 11 landing site.

4. Armstrong’s famous words uttered when stepping on the Moon were misheard. Most people on Earth heard, “That’s one small step for man, one giant leap for mankind.” But Armstrong was adamant that what he had actually said was, “That’s one small step foraman, one giant leap for mankind.” “It’s just that people just didn’t hear [the ‘a’],” Armstrongtoldthe press once he was back on Earth. In 2006, puter programmer used a piece of software toanalyzeArmstrong’s words and found that the “a” was indeed there but was likely not heard because of radio static.

5. Aldrin became the first person to celebrate the Lord’s Supper on the Moon. munion bread was carried in a plastic packet, the way regular inflight food is wrapped. He also carried the wine in a vial and poured it into a small silver chalice. Before munion, Aldrin read fromJohn 15:5, which he had handwritten on a scrap of paper—”I am the vine, you are the branches. Whoever remains in me, and I in him, will bear much fruit, for you can do nothing without me.” munion ceremony was dramatized in an episode of From the Earth to the Moon, a twelve-part HBO television miniseries from 1998. Buzz Aldrin was played by actor Bryan Cranston.