Landing: One giant leap for mankind

23 July 2019

Interview with 

Amy Shira Teitel, Spaceflight Historian

ASTRONAUT-ON-MOON

An astronaut standing on the Moon's surface

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We’ve just heard about how the Apollo 11 crew; Michael Collins, Buzz Aldrin and Neil Armstong, navigated their way towards the moon. After an intensive hunt for a landing site, NASA eventually chose a site called the Sea of Tranquility. One of the darker patches you see when you look up at the Moon, with the lunar module touching down on the evening of July 20th 1969. And just a few hours later, in the early morning of the 21st of July, Neil Armstrong made his way out of the lunar module, towards the moon’s surface. It was nineteen minutes later that Buzz Aldrin joined Neil Armstrong, adding his footprints on the moon’s dusty surface as the second person to set foot there. But once the crew had touched down, once the Eagle had landed, what did they actually do? Adam Murphy heard more from spaceflight historian Amy Teitel...

Amy - The first thing the crew did was go through the stay/no stay. So NASA had to double check that all of the systems on board, all of the consumables, everything was fine to support the lunar stay. The crew was actually supposed to have a rest period first because NASA wanted them, you know, bright eyed bushy tailed walking on the moon for the first time. The crew was so excited that NASA opted for the alternate mission plan of moving up the spacewalk to the first thing after the landing. Now that first thing was seven hours later - it took seven hours to prepare the lunar module for them to actually go outside. At which point they did take their first steps on the moon and were outside for about two and a half hours before returning to the lunar module, taking a quick nap and going back up to meet Mike Collins in the command module.

Adam - How concerned were they with advancing science on Apollo 11?

Amy - Science was not the key concern on Apollo 11. Apollo 11 was the mission to land.. that was its goal - was just to get there, to do the landing, to grab some stuff and to come home. You know, to that end there was Neil Armstrong's first task. So he got out of the lunar module first, as we know, he said the famous first words on the moon. His first job while Buzz was getting ready to follow him out was to actually pick up a contingency sample and this was just from any area near him on the surface. Just pick something up, stick it in your leg pocket. That was in case anything went wrong and the crew had to jump into the lunar module and leave on a dime.

Adam - It was a case of grab something - anything - just so you'd have something if everything went sideways. But what was the third man - Michael Collins: the loneliest man in the solar system - up to while Aldrin and Armstrong were bouncing around on the moon?

Amy - Mike Collins had the - depending on your perspective - the enviable or very unenviable job of waiting in lunar orbit for his moonwalking crewmates to come back. So his job was really to make sure that everything onboard the command module was running perfectly. That was in case, you know, if anything happened on the moon and Neil Armstrong and Buzz Aldrin couldn't get back up, Mike Collins was coming home alone, so he had to make sure that at every point he was ready to do that trans Earth injection burn. So fire the engine to leave lunar orbit and go back to the Earth, but also make sure that everything was working perfectly so that when his crewmates came back they could leave whenever they had to - if they had to leave before the mission was scheduled to actually have them leave lunar orbit.

The other thing he was doing was taking a lot of photographs and running some experiments from orbit. Now this is where - like I said - NASA didn't have the best detailed image of the landing sites for Apollo 11. It had data, of course, but the later missions, all of the orbital missions took really detailed pictures of specific surface areas from orbit so that NASA could make very deliberate decisions of “OK, well this is a geologically interesting area that we have to land in so let's put this mission here” or “this structure looks very neat”. You know it was really kind of gathering more data so that the later missions could return even more interesting science.

Adam - Although they were walking on the moon's surface for just a couple of hours, they were on the moon for a little over 21 hours. At the end of that they left behind a few trinkets, including a gold olive branch to symbolise peace and an Apollo 1 mission patch to commemorate the three men who died in an accident on the runway during Apollo 1. But, once they were done how did Armstrong and Aldrin meet up with Collins again after mankind's great leap?

Amy - Getting the crew back together after moonwalk was not the easiest part of the mission. It involved - what is technically called - a rendezvous and docking, which is basically just having the two spacecraft meet up in orbit and then physically connect and do a dock so that you can take out the probe and drogue apparatus that would connect the two spacecraft. You move that out, you have a tunnel and you can move between them. So that's what was needed to have the astronauts move back from the lunar module into the command module.

Now that's a little bit easier said than done. Thankfully orbital mechanics and physics mean that once you're in orbit you're pretty steadily in orbit and you can just adjust your orbit so that you come up and meet at the exact point. The problem was that the lunar orbital environment is not the same as the Earth. So practicing on Earth - in Earth orbit rather - isn't the same as doing it on the moon and the moon's gravity is also not uniform. The moon has these things called mass concentrations or mascons, which means that the gravity is a little bit wonky depending on where you are in orbit.

It all came down to having the most detailed understanding of the lunar orbital environment - how a rendezvous has to work with one spacecraft catching up to the other by just adjusting its orbit and having the brilliant software engineers write it all into the computer so that it basically took care of itself.

Adam - Brilliant software engineers just like Norm Sears who Izzie spoke to earlier. But looking back with 50 years hindsight how risky was the whole endeavor.

Amy - Well the thing with Space is that everything is trying to kill you. So dangerous would be the keyword. You know when think about the reality of what they're doing. We now almost see flying in space as routine but you're sitting on top of a giant rocket that is effectively a controlled explosion, punting you into space which then has multiple pieces that have to be put together. That has to punt you to the moon and then you're dealing with this foreign alien environment, landing on the surface that no one had done before. And it's not like crossing the oceans to the Americas with Christopher Columbus. You can't breathe on the moon or until the land. It's also trying to kill you. Everything about it - if anything goes wrong the chances were bad. But NASA did have this rule of three nines - everything had to be ninety nine point nine percent reliable. Now that obviously doesn't rule out every problem. Apollo 13 - it notably had some issues onboard with a ruptured oxygen tank but NASA and its contractors and subcontractors who built all of the spacecrafts, who worked on all of the software worked tirelessly to make sure that it had the highest rate of success possible. So given that everything on a mission to the moon was trying to kill them, it was also way safer than their previous jobs as test pilots which is the weirdest thing about it.

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