NOVA; To the Moon; Interview with Steve Bales, former NASA engineer and flight controller, part 2 of 3

Okay, how sophisticated were they put it in terms of what a kid would find it? We had two computing systems on the Apollo spacecraft and in the landing module, the primary one was called the pings. It was at a 64,000 words of memory only. It would run at 833 instructions per second. Today, if you gave that to your kid, he would throw it away. It wouldn't be worth it. He'd say, what have you given me? And yet, because the ingenuity of the MIT engineers that coded every line and worried about every instruction and thought and sweat over every piece of code in that machine, the 64,000 word machine running at 833 instructions per second could do things like start the limb guidance computer at a 50,000 feet, navigate and control that ship all the way down to 3,000 feet where the astronauts could manually take over.

And at the same time, it was controlling this ship in attitude. It was given a crew readouts. It was sending 100 pieces of information a second to the ground. That's quite remarkable for that kind of a computer. So it was all in the programming? It was all in the programming. That people that really worked and worked and worked to get it right, and then tested and tested and tested until it was right. That's amazing. And even then, they almost didn't get it right, because we almost had to abort. But it was one of those really subtle, subtle failures that we ran into the first flight. Before we get to that, how much more complex were the flight operations for Apollo versus Gemini? Sure. Once in Gemini that we understood the rendezvous, then many of the other operations were the same as had been in Mercury. Yes, there were new systems. So that was different. New fuel cells, new things to learn.

But once you had gotten to learn the new systems and done the rendezvous, it was still Earth orbit. And there were a lot of things that you knew and could build on for Mercury. You went out to the moon, the big thing that changed was your three days away. And not only that, you had to navigate the 250,000 miles, not 200 miles. And since the onboard systems still weren't that sophisticated, they couldn't do their own navigation. The ground had to track them with radar and then tell them where they were at all the time. And even we didn't precisely know the geometric conditions of the moon. I mean, we knew it very well, but we were afraid we didn't know it perfectly. And you were going to have to know it perfectly. Think about it. You're 250,000 miles away and you'd better know where that spaceship is to within 100 feet. 1969, not 1999. That was a big, big thing in my mind that was different. And if you missed it, nobody was going to figure it out, perhaps it was too late.

Were you involved at all, where were you when the fire happened? The Apollo 1 fire was a tremendous setback. You had to realize that I was working closely with a number of other people, and we were youngsters. And you know, astronauts may have been through that and lost comrades. Our more mature experience, the flight directors had probably been through that. Jim Krants, I'm sure, had been through that. Glenn probably had been through it. But when you're 23 and 24 and you'd never lost a friend or you'd never even lost a co-worker to an accident, and then all of a sudden, very publicly, here's this fire and no immediate understanding of what caused it and no immediate understanding of what it was going to do to your program and your chance to fly the space in space. And also the tragedy of losing people that you knew that it was a grievous setback to

us. But it wasn't a disastrous setback. It was a setback, but it wasn't a disaster in that. Within a few months, everybody started to pull together. You could see the people in NASA rallying around certain key leaders, and NASA handled that by bringing in one of the other center directors, and he took charge of the investigation. And when you're young like that, you look up to certain people to say, let's rally around them. Hey, they're showing us the delay. It can be done. We can do on. We can move on. We can do other things. And there were people like Chris Kraft and other center directors who would say, look, those guys know what has to be done. Let's do our part and follow that. NASA said he came into the mission control, came in the next day of the control room after the fire. He said, you could tell all these young people were just dead. Yeah.

And see, he'd been around. He'd been through that. He'd been through test flights. He'd lost. But Chris Kraft had been in a test flight business, and I've never asked him personally, but I know that he'd been in situations where they'd lost people. And so he knew you'd have to pick up in the flight operations. We were going to do something again, but knew that we would be looking to them to give us the leadership, which we needed all the way through the whole program. Tell me about the buildup to Apollo 11. What was your specific role in Apollo 11? What were you going to be? You were in the hot seat. There were about seven people in the hot seat in Apollo 11. My job was to monitor all the guidance systems, which included the computer, but also the radar, the inertial navigation system, the pointing instruments, and all the things that were needed to guide the spaceship from orbit around the moon down to the landing site. And that included monitoring information in the control center. But as much as that, it also included listening, listening to the crew in a way they were saying

it, helping to write the procedures they used to go through the power-up and actually the final landing of the moon. So it involved a lot of things in preparation and involved those real-time monitoring when it was a ton of flying. How hard did you guys practice this stuff in Mission Company? Practicing. Practicing. We would have been worthless without practicing. As much as we studied and listened to people and did things, and there were some really, really true planning leaders in NASA that ran the theoretical equations that determined the way the approaches we ought to use to go to the moon. But in the end, the actual detail part of it, in the control center, we were responsible to do. And the way you learn that is you practice and practice with simulations. Crews are in the trainers during the control center. You try to do a normal, and then you never see the normal again because the people are

inserting faults and what have you. First time we ran the first lunar landing simulation was almost as intense as the first time we actually landed on the moon. And I remember I was in a position that had quite a bit of responsibility, and as we were at the start to run, the first run, I heard this voice say, I'm going to plug in here. And I saw this plug go into my console, and I just got it stopped, and it was Chris Kraft. He doesn't usually come around and plug in to people's consoles. So I knew that he was quite concerned about this particular position, and he wanted to know, I'm sure, if I was going to be able to do the job. And we got into a situation where I had to call in a board, and I said, I know I'm doing the right thing, but I'd better be doing the right thing because a lot of scrutiny here. And it was interesting.

I was waiting for the debriefing, and I said, did I get this right? Did I get this right? And the first thing the simulation people said was, we don't know why you aborted, because they know all the things they put in. And I said, well, look, I saw this information. I saw an navigation go wrong, and I would have done the same thing, and I had a board. If I'm wrong, I got to know. They went back, and they found out there was a mistake in their simulator, and they put in a case, or it was failing, and it shouldn't have been failing. And they came out about two minutes later and said, uh-oh, we inserted this fault. So I really had called the right thing. Right before the actual landing, you guys have been running simulations, and I know I've heard, I've talked to craft about this, a craft about this. Things had not been going great. You guys have been able to try that to me, right? We had been having a lot of problems with simulations. We would call one right, and then something would happen, and we'd either call it wrong, or we would be too conservative, or we wouldn't be conservative enough. We'd either call off the landing too early, or we would take a little too far in a crew

with crash, and we were starting to, we had gone through so many problems that we were starting to wonder, you know, were we really on top of this game. And apparently there was a lot more pressure on the leaders than there were even on us. And I'm going to have to ask you something. We had been having a lot of difficulty with the simulations. Each of us had been trying hard, we thought we were executing the rules and the procedures the way we're supposed to. But the result hadn't been working out. We had either been too conservative, and we'd been aborting when we shouldn't have or didn't need to. We had been sometimes pressing it, and actually crashing in the simulator when it could have been prevented, at least in retrospect. You could look back and say it could have been prevented. And it was a nervous time, I mean, we felt we were trying to do the right things. Nobody was making any obvious mistakes.

They were subtle, and they had to do with teamwork, and the team wasn't just quite together. And of course, this is the first thing this time has ever been done. So who knew what quite together really was? And although we had successes, we also had failures. And I think when we finally quit and rate our last runs, we knew we were prepared, but we also knew that if things didn't go together right, something could happen that wasn't exactly what you wanted. What was the chances move at this point? Well I think everybody's mood was confidence and yet concern. That sounds crazy. Okay, we're at your comments, but concerned, okay. Okay, it's the day of the landing. Okay, you're going to go to the landing. What was the mood? What did crafts or crafts say? Describe it.

The day of the landing was so, tension was so thick, you could have cut it with a knife. I'll tell you, I worked in the control center. I looked up to the visitor's room. Anybody that had ever made a contribution to the space program was up in that room. And I didn't know two-thirds of them. The ones I knew were enough to be awesome. There was Werner von Braun, you know, who movies have been made in this man's life. There was the Administrator of NASA. There was all the center directors of NASA. But even if there had been nobody in the room, I could have felt the tension. You know, this was it. This was really it. Now, you've got seven, 25, 26-year-old young men. And we were all young men at the time. There were no women involved, really. They hadn't been involved in the program much. So you have 20, you have seven young engineers, 25-years-old. Each of us think we know exactly what we should do. Each of us smart enough to know that if things don't come together right, something could really happen.

And if it really happened bad, what was I going to do? You know, I couldn't keep working at NASA. I didn't know if I could keep working anywhere. I just want to go hide in the hole. So at the same time, we'd been trained, and we felt sure we could do the right thing. So here you are. You're confident, but you're scared to death. That sounds crazy. How can you be confident and scared to death? But that's exactly the way I felt. Confident and scared to death. And I said, and at that time, you look around and say, who's going to be with us? What's going to happen if this doesn't work the way we're trying to make it work? About that time, five minutes before the final landing, and the crew was not yet in acquisition of signal, Flight Director said, everybody go on a special loop. And then he said this, said, folks, we are going to land today, and we are all going to work together, and it's going to come out fine. But no matter what happens, when we go out of this room,

I'm going to be with you. You don't know the difference that made to me, and I believe it made that kind of a difference to every person in that room, because we knew that if something did happen, and even though we did our very best, something that was bigger than any of us happened, and it would have worked out badly, everybody would have put their reputation on the line that was in our control center and walked out together, and all of us would have stood up for that failure. And a lot. A lot. Really did. Okay, good. So now, they're coming down to the lunar surface. Okay. What's going on? Okay. Now, first thing to happen, we finally get data, and we had terrible data problems. And we finally get data. I realized that we're going toward the moon, 13 miles an hour faster than we should be. And the computer doesn't know it,

and our ground rate ours tell us. And that doesn't sound like much. And yet, it's almost enough that we have to abort the mission, because we have a rule that says, if it gets up to 20 miles an hour, we're going to stop this mission, because you could actually literally crash into the moon and not know it, or you're an automatic pilot. So now we're really, I'm worried. And I tell the flight director, we've got an air, and it's not growing, and I think we're going to be all right. We get to 30,000 feet, the landing radar locks on. It says, yeah, you're going a little too fast. It tells the computer. The computer says, oh, guys, I'll just correct that, and it quietly corrects it, and everything's fine. We're about four or five minutes into the mission, and we're four minutes into the landing. I think, hey, that was our big problem. We're going to be okay. 30 seconds later, I hear 1201. I said, what, what, what? That's an alarm. I know it's an alarm. And then I see it on telemetry, on my console, 1201.

And I'm frantically trying to remember what 1201 is, because it's one of those strange alarms that we're never supposed to get. And I have a back room, and he's helping me. He says, hey, that's the overflow alarm. And I remember, oh, my gosh, yes, that's the overflow alarm. And our rule on it is soft. And it says something like, if it doesn't happen too much, and we haven't defined too much, we just said if it doesn't happen too much, and if everything else is okay with the computer system, we'll keep going on. Overflow. Overflow means that every second the computer is trying to do so many instructions and so much work. Then it starts again, and it goes back, and it does the same things the next second. It's called a fixed cycle. And those days, that was the only way they could get the computer to do everything they had to do. They said, do these things on this second. I don't care if you don't have them all done or not, start doing the most important things again the next second. Now we had tested the computer and tested it and tested it, and it had never given an overflow for a year.

Never, even in our simulations, had this exact type of alarm. We'd had similar ones, but not this one. So that said that something didn't get done that second. What was it? Was it something that was really important or something that didn't matter too much? We didn't have a lot of parameters to tell us. The only way we could tell it was by inference. We had to infer what was going on. The first thing I looked at was the computer's knowledge of speed and altitude. They were okay. Still knew where it was. Still knew how fast it was going. Then I looked at the computer's guidance signals. What was it trying to do with the spaceship? And it was trying to do the things that it had been doing. It was gently guiding the ship toward the ground. Then I looked and saw was another one of these alarms happening because it could be like a cancer. You know, maybe it'll happen now. It won't hurt, but it'll happen five seconds later. And then it'll really start going. That's all the data we had to diagnose with. Based on that, I made a judgment about 10 seconds after the fact that we were go.

And I said, go, we're going to continue. Were somebody asking you what to do? The flight director says, what are we? Both the flight director and the crew said, give us a reading on the alarm. And I said, flight, we're going at alarm. Charlie Duke, the capcom immediately voiced that up to the crew. Then what happened? Coming. We'll go to the next day. All right. How exciting was that moment and then what was to come? The moment was at a fever pitch because I had to make a decision. And I was sure I was making the right decision based on the rules. But I wasn't sure how it was going to turn out. Nobody was. We didn't have enough information to really tell us everything. There was nobody who had enough information to tell us everything. So I made the best decision I could. And I said, go. And I said it as loud as I could. Probably halfway because I was scared and halfway because I wanted to make Darnwell's shirt that the flight director heard me. Because a lot of people are talking on the loop at that same time. I said, go as loud as I could. He told the Capcom to relate to the crew.

They said, go. And they didn't even look back. They just kept going. Two minutes later, we get another one. Almost the same thing. It's 1202. Almost the same type. I'm thinking, uh-oh, we're in. We could really begin in trouble now. We shouldn't have any alarms. Now we've had two. But it's far enough apart. It's two minutes past. We still know the speed. We still know the altitude. So I said, go again as loud as I could. So, call the two. Call the two. Call the two. It's been two minutes since we had the last alarm. But we shouldn't be getting any alarms. I mean, we should have zero alarms. Now we've had two. I decided it's been long enough since the first one. It's probably not enough to make a stop. Look around at everything else. We still have good speed. We still have good altitude. We still have good guidance commands. The ship is still stable. Everything says, we ought to keep going. So I said, let's go.

Let's keep going. Let's go on that alarm. In fact, I said, same type. We're go. Charlie Duke relates that to the crew. Again, they don't look back. All they want to know is they're go. And they forget about it immediately. They don't know how we figured it out or why we figured it out. And at that point, they don't care why we figured it out. Their job is to start guiding themselves to the, to the moon. Now, had the computer program expand to recognize that, you know, that the border alarms could trigger themselves and that kind of, what happened? Okay. What had happened? These alarms were never in there for real time or occurred during the mission. They were put in there way back in the first, in the beginning of the software, to help the people diagnose the software and test and check it out. They were never meant to happen during the mission. And the only reason it happened had nothing to do with the software program. Had to do with a piece of hardware that failed and sent thousands of instructions to the computer that said, look at me, look at me. And in fact, they were on the rendezvous radar, which wasn't even being used at the time.

But we'd always told the computer never ignore important hardware. So this failure was intermittent. Sometimes it would send thousands of instructions in a second. And then it would stop. So the computer that one second had had to process thousands of worstless instructions, thank goodness it had been programmed in a very smart way that did the most important things first. The things that weren't done that second were things like crew display, which you could live without. And it was good enough to keep going on. Also thank goodness that error that hardware failure was intermittent and stopped after a few seconds, drifted and then only came back two minutes later. We ended up having seven program alarms before we ended up landing on the moon. And each one was a cause of the hardware that had drifted into failure, sent thousands of information bits to the computer. Poor computer had to try to deal with them. Couldn't deal with it that second gave up, started the cycle again and told us about it. So the irony is that mission could have been aborted by a piece of software or hardware

that was never intended to be there for the mission. For that part of the mission. The irony is we left the rendezvous radar on because we were afraid if we ever had an abort, we didn't want to take the time to warm it up. But it was a convenience item. We could have left it off. We could have put it in another mode so the computer was never reading it. We never in a world dreamed we would have a subtle failure that would send...