Six minutes before the Eagle Lunar Module was set to touchdown on the Moon, the tense voice of astronaut Neil Armstrong came through to Mission Control in Houston.
A yellow caution light was flashing on the computer in the cockpit, the 1202 alarm, and neither Armstrong nor fellow astronaut Buzz Aldrin knew what it meant. Should they continue to the Moon or abort the Apollo 11 Mission?
The call would come from a 26-year-old NASA guidance officer named Steve Bales.
Fifty years ago, men landed on the Moon because Bales said one word, “go”.
Steve Bales: I used to go out and look at the stars at night, we lived in a small farming community [in Iowa] and my father would point out a few of the constellations. And that got me really interested in space.
And then, as listeners may know, we had this shock in the United States called Sputnik and that really incentivised me, and many others in my age group, to do something if we could. I was pretty good at math and science and Iowa State had a good engineering school and I went there. And the last year that I was in school, for the summer I got an internship offer from Houston which was the best thing that probably ever happened to me.
Jesse Mulligan: Can you just help our younger listeners out? What was Sputnik and why was that such a motivating event?
SB: Sputnik was the first satellite launched into orbit and it was not by the United States it was by the Soviet Union.
We could have probably launched one, but for some reason didn't think it was that important. It was tremendously important, the world all of a sudden started to think the Soviet Union is ahead of the United States - it wasn't the case, but it appeared to be the case. And then, a few years later, they launched the first human into space, Yuri Gagarin, again they were first.
We were trying to catch up, we did catch up, but only caught up after President Kennedy made the challenge ‘Let's go to the Moon’.
It's hard to describe to your younger listeners but there was tremendous anxiety here in the States about are we behind? Can we catch up? What are we supposed to do? And the Apollo program was a big part of solving that problem.
JM: And people like you felt a sense of service to the country, like you wanted to be part of the solution?
SB: Absolutely, when I was in college we had our first launches of Mercury and the Apollo program was yet a dim hope in the future. But fortunately, when I was an intern, they were just building the new Control Center in Houston.
One of my jobs as an intern was be a tour guide and so I had to learn at least a little something about what each of the positions did. And to do that I had a chance to go to talk to the people that would actually be sitting there and doing things for the first Gemini missions.
And after I did that summer, there wasn't any place else I was going to go, I immediately started to talk to everyone there. How do I get a job? Who do I talk to? Where do I make an application? And that really helped me get an offer from Houston the next fall.
JM: What was your job?
SB: My job was called the guidance officer. The guidance officer sits in Mission Control at one of those consoles and is responsible for all the functions of the guidance system. Now the heart of the guidance system is something called the Apollo computer. But the guidance system is a lot more than that, it's the computer taking in information from radar, from accelerometers, from rendezvous radars and figuring out where it is and how fast it's going and where it's going to go, and guiding the vehicle to the ground in the case of the lunar descent.
In the descent phase, for the first 10 minutes, it's automated control. The crew can't even see the moon for all that time. And so they’re relying on this small computer, who is sensing all these other instruments, to take them there. And my job was to make sure that system as a whole was doing everything right. And if there was a problem to make a call on whether we should continue or not, continue based on the health of the guidance system.
JM: You were just 26 years old and a lot of them [at Mission Control] were young, most of them, was youth an advantage because you maybe didn't know how scared you should have been?
SB: It probably was and all the controllers were 27, 28 - I was 26, probably the youngest one was 26. Flight director Gene Kranz was 36, he was the oldest one, he was the old head and he really was the leader.
And we were lucky in that we came on at the time when the people that probably could have done a better job than us were already having to move up and manage the program, so it would be successful.
And so they needed people to come in, there wasn't a lot of experience in the area I was in, there was some guidance, but not a great amount, especially on how to monitor it during a mission. So I had a chance to learn from the ground up and listen to others and watch others during the Gemini program and be ready for the Apollo program.
JM: Buzz Aldrin and Neil Armstrong must have seemed like old men to you.
SB: They were, but you know these days I believe the astronauts and flight controllers are much closer in age and probably relationship. Buzz Aldrin and Neil were like heroes from the Korean War, and so were the others, and also they were gone a lot from Houston. They were all over the country, all over the world, training at various simulators and facilities. The training system for Apollo, at that time, was at Cape Kennedy so their simulators were Cape Kennedy and when we were training we would be in Houston. So, I knew who they were, and they knew who we were, but we didn't meet a lot.
JM: What was it like walking into work that day, the day of the Moon landing 50 years ago?
SB: We walked into the room at seven in the morning Houston time, it was like walking into a place where you could have cut the tension with a knife. And it got nothing but worse for the next eight hours.
Because we had eight hours of very, very difficult work. We had to power up the vehicle, all the different flight controllers had big responsibilities there. Mine was to make sure the computer knew where it was aligned, the programs were functioning properly … it was just hard work after hard work – for an hour and a half we would have communications with the vehicle and we would work as hard as you can imagine for an hour and a half, then they'd be gone behind the Moon for 30 minutes. We’d keep working because we had to be ready to start doing different things, the next revolution. And we did that, until finally everything was ready, the vehicle separated and it went behind the Moon for the last time.
JM: Can you tell us about a guy called Gene Kranz? He was the flight director, how did he prepare your young team for that incredible day back in July 1969?
SB: He was an incredible leader and he knew each of us and how we would all react. I cannot imagine anyone else, I'm sure others could have done it, but I personally can't imagine another man being in control of this team during these 13 minutes to landing.
Many of your listeners may be more familiar with him from the movie Apollo 13 - ‘Failure is not an option’.
Gene knew that he had a bunch of young guys ready to do what they had to do, but he also knew that It would be good for him to remind us what we were going to do just before the vehicle came into contact.
So he called us to a private loop and he said, ‘this is it, this is what we've worked for for years. This is what you're meant to do and we're going to do it today.’
Then he said something I'll never forget.
He said: ‘Whatever happens, when we walk out of this room we walk out as a team.’ You can't imagine how important that was to me, because I knew that we had three things that could happen to us; we were either going to land, we were going to abort, or we were going to crash. And we were praying that the first one was the one that would happen. What he said really, really helped to get ready and I still can remember that as clearly as if he said it yesterday.
JM: Minutes before the Eagle was meant to land you hear Neil Armstrong asking for a reading on an alarm going off the Lunar Module. Could you tell from his voice that there was real concern, it was quite rare to hear his voice right?
SB: Neil said they didn't know what it was. Actually the only reason we knew about it was we'd seen that in the simulation just before the launch. This alarm was never supposed to come up, it was only to come up as the computer was getting overloaded. And there'd been run after run, after run in training - nothing like it ever happened.
But there was a problem; unknown to us there was overloading in the computer and right at that time it had hit 100 percent, couldn't get everything done and said, ‘I didn't get everything done, your call’, essentially is what was being said. My back room reminded me this is an alarm, if it doesn't come too fast, we're okay as long as everything else is okay.
And since I had ability to look at the speed and the altitude and the rate of descent, the guidance commands and everything else, the vehicle seemed to be doing fine, the computer was doing fine and based on that, we said ‘go’, but it took us 15 to 18 seconds to make up our mind, because it really was a shock.
And that doesn't sound like a long time, but in powered descent that's an eternity. And we, thank the Lord, managed to come up with an answer that was the right one.
Charlie Duke heard me say it, I screamed it almost, and he immediately said: ‘Eagle we’ve got your go on that alarm’.
Buzz Aldrin calls up another display right after that and it happens again, we said the same thing ‘you’re go’. These were all at about 35,000 feet, so we told the crew, don't call that display up again we’ll monitor these parameters on the ground for you.
And they did, they just stayed off the diski, the diski is shorthand for the crew keyboard.
We managed to go all the way down to 7500 feet at that point, the computer pitches the vehicle up, we've killed off enough velocity so they can look down and the crew can see the moon, trying to figure out where they're going to land.
And quickly they see that they've gone about four miles too far down range, they had an idea this would happen, we told them it was probably going to happen. And as they get lower and lower, they see the terrain is really rough, where the computer’s about to take them, and Neil takes over manually.
The other problem we have is when you're in this program, it works even harder and we start getting more alarms, and so I had to do the same thing three more times. We had three more of these 1201, 1202 alarms and I had to give a ‘go’ each time - ‘we're continuing to go’.
We worked down the vehicle down to about a thousand feet and then Neil takes over manually because he's going to have to guide across a big crater the size of a football field.
The good news is, when he takes over manually, that relieves the computer of a lot of its work and the alarms go away, there are no more alarms after that.
But then we have big problems with fuel. He's about to run out of fuel, we are getting close to it. And if you listen to the air-to-ground that's what you hear, the word ‘the 90 seconds’ and then ‘60 seconds’ and we never thought we'd get below 90 seconds.
We’re down to 60 seconds and the propulsion engineer Bob Carlton has got his stopwatch going, he gets down to 30 seconds and all of a sudden we're picking up dust and then the contact light, and then ‘Houston Tranquility Base here, the Eagle has landed’.
JM: How much certainty did you have that saying ‘go’ was the right thing to do?
SB: You know, there was no certainty at all. There's a school of thought that says good outcomes don't mean there were good decisions. That may be true, but it's much better to have a good outcome.
We could have gotten in big trouble, no question about it, especially when we got low, when we got below 3000 feet. Once we got to 700 feet, he had some other options to manually land, but there was no guarantee that what we were doing was right, we were doing the best thing that we knew how to do.
If we just said ‘stop’, the lower you get the more risky it is because then the vehicle has to pitch around and try to make it back up into orbit.
So trading off risk versus risk, I'm convinced we made the right decision, but it was not guaranteed that it would work out well.
JM: Have you thought about the ratio of luck to preparation on that day?
SB: We were lucky because we saw a similar case two weeks before the landing. And we got into big argument about what we would have done. I aborted the mission when that thing came up, it was a similar alarm and I aborted the mission and we got into a big argument about what should we do?
And that's when Gene said ‘I want you to go off and make sure that you have rules to follow when one of these alarms come up’. I said ‘Gene, there is no way these are supposed to come up, these are put in there for software checkout’.
He said: ‘I don’t care what you think, you go do it’. And that's what we did …if we get certain alarms, we're going to try to keep going as long as they're not coming too fast. Other alarms, we can't do anything, we have to stop.
So, in that sense, we were lucky and prepared I guess you would say.
JM: How did you feel when you heard those words Tranquility Base here the Eagle has landed?
SB: I'll tell you what, there's a surge of ‘yes!’ for about 10 seconds and then we had to get ready for a lot of things on the surface. If you listen to the air-to-ground, instead of saying ‘go’ now we start saying ‘stay’, just to make sure we’re absolutely clear what we want the crew to do.
And so we had to get ready if something went wrong with the environmental system or the vehicle started to tip or something else happened, we had to get ready to go in two minutes. And that was intensive time.
And then once we get by the two-minute part, we have to get ready to go for there's another stay/go decision to make at 10 more minutes, we had to get ready to do that.
So it was almost impossible to understand what had really happened, other than we knew they were on the surface, but there was no time to enjoy it, be glad about it or anything else because we could have gotten right back in and had to lift off.
We're grateful that everything was calm after they landed and we were able to stay for the 24 hours.
JM: Did you get to watch the moonwalk?
SB: I'll tell you funny story, Gene comes in and says; ‘I want you to go with me to the press conference’, there's a press conference after every shift and you can imagine it was a big press conference after this one. And I was so tired and I said; ‘Gene, do I have to go?’
He said, ‘Yeah, you do because somebody may ask something about alarms'.
Well, I go over to this room, this room which is packed as you can imagine, and I was so tired that I almost fell asleep in a press conference. I remember nobody asked about alarms because really at that time, nobody's had chance to brief them on it. And they were more interested in what we felt and what was going on with the crew and that sort of thing.
And they let us go early because one press reporter said, ‘You guys look like you're beat. I'm sure you'll come back and explain more later’. And that was the best thing a press person has ever said to me in my life.
So we all go out as a team, and we go back over to an area, a lounge behind Mission Control and we watch it together. I mean, we all watch him come down the ladder, and step off the moon, what an incredible, incredible thing that was.
And then I just went to sleep in one of the bunk rooms that was behind Mission Control, because I had to get up the next day and monitor the launch phase, the ascent phase.
But that's how I watched it, I watched it with the team of people that landed us on the Moon.
JM: Have you reflected on why the Apollo Mission worked, not just from a technical aspect, but you know everything from the political will to the leadership and the dedication it takes to make something like this happen?
SB: It took a person like John Kennedy to have the vision, and even he wondered if he'd had the right vision according to some of the more recent historians studying papers and other things.
The other thing that happened, that I don't think anyone realised, is how much technological advance the Apollo program brought about in our country, and around the world too.
I've read recently that 50 percent of the transistors that were made in the 60s, were made because of the Apollo program. There just was a drive, we had to make lots of things: software, transistors, monitoring procedures, communications in space, and that really were beneficial to the country even more than I thought.
JM: Thinking about your childhood in Iowa, looking up at the stars, do you now hold your gaze for just a little longer, when you look at the Moon?
SB: I do and I'm grateful because if you think about it, it was a wonderful success, it was one of the few times that the world's attention was held on something and it was positive.
This was a positive thing and so I look up and I say thanks that it worked so well. And thanks that we can look up and we don't have to worry about something that went wrong. When I see the Moon from time to time, I'm grateful for all those things.