Apollo Guidance Computer Activities

AGC Conference 3 - After Apollo: Spinoffs and Legacies

Apollo Guidance Computer History Project

Third conference

November 30, 2001

Dave Bates and Jack Poundstone

After Apollo: Spinoffs and Legacies

SANDY BROWN: I was curious to know what happens after the Apollo program. What happens to the little old ladies, for example?


HERB BRISS: No, we went on to a lot of things.

ED BLONDIN: Lot of programs.

ED DUGGAN: Oh, these things got projected forward, I think. You gained a toolkit for the next proposal.

JACK POUNDSTONE: More important, from the contractor’s point of view, the lessons that were learned from Apollo were just applied to the next generation.

ED BLONDIN: You had Trident.

ELDON HALL: They went into the Navy programs and a lot of other programs. The Navy started it - Apollo was just a second-generation Navy program forward.

ED DUGGAN: And they picked up a lot of the things we learned in Apollo. Well, we had Dave Gold in those programs, and he was a single minded individual. He’d make decisions on the spot. Sometimes with a lot of pain.

JACK POUNDSTONE: From an individual’s point of view, as you’ve heard here, in some cases the careers continued on Apollo or as in other places, the careers moved somewhere else. And like I said, for some who stayed on Apollo too long, like Eldon, it didn’t work out too well.

HUGH BLAIR-SMITH: Well, how did it come about that once we had to give up being architects of spacecraft computer systems, we got into fault tolerance. Can you trace how that came about?

ELDON HALL: Yes, it actually started in Apollo. Near the end, before there were any flights or anything, and before computers could be accepted as reliable, Paul Ebersol gave us a contract to build a dual computer. I wanted to figure out what the name of that thing was.

HUGH BLAIR-SMITH: DCA, they called it.

ELDON HALL: Strap down IMU and a dual computer, DCA. That combination was in case the mainline thing didn’t work. Paul Ebersol supported that and pushed it. Well, first of all, the Apollo computer had fault tolerance, and then the DCA started a different configuration of fault tolerance. And that led to other forms of fault tolerance like multi-processors and so forth and a lot of that is still supported by NASA,   looking towards the shuttle. Even though eventually we lost almost all contributions into the shuttle, that's where all the processor concepts got started. So does that answer your question?

HUGH BLAIR-SMITH: Yes. I was just bringing that up to ask what became of people afterwards? In our case, we took the same bunch of people and I think essentially changed direction. It was very clear that after Apollo that NASA felt, perhaps correctly, that the industry was able to build spacecraft computers, which they obviously hadn't been before. And so in some sense we taught the world how to do that.

ELDON HALL: Yes, in some measure. So we became obsolete.

JACK POUNDSTONE: We did ourselves out of a job.  That hurt our lives because we were nonprofit.

ELDON HALL: They had a goal just to say the guy that makes the mistakes always gets more attention. And everybody comes in and helps themselves to the mistakes.

DAVE BATES: So then on my side of the house, we kept that design agency concept even to today, on the Trident program.

ED DUGGAN: There was some major commercial spinoffs, though, of the Apollo.

DAVE BATES: Well, there some major companies, like Intermetrics with Miller, were developed. What about the space group over here under Eisenhower? That moved off. There were a lot of spinoffs. In fact, Doc made the comment at one time that his job was to expand technology.

ELDON HALL: Yes, that was Doc’s whole concept, right.

DAVE BATES: And then he got pissed off when everybody left.

ELDON HALL: Not really.

DAVE BATES: Oh, yes. I don’t know whether it was Doc or somebody else, because we ran into a situation where other companies were starting up and they were taking people off and they said, "Well, you know, why are you hiring these people?" And I got caught in the middle of one of them where they were setting up a company. I think it was even Miller’s company, that they said, "Well, why didn’t you let them know?" Because they would keep them happy there. Well, they didn’t want to be happy there.

ELDON HALL: Well, after Doc was going downhill, Dave Driscoll got very upset if people left.

JACK POUNDSTONE: That might make an interesting part of your report if you could sort of identify all of the spinoffs and companies that were formed out of this group.

CLINE FRASIER: There’s one spinoff from this program that I don’t think is generally recognized, and I've certainly never seen it in print. One of the problems we had with the Apollo computer was that it was probably one of the first developments that went through extensive random vibration testing. We found lots of problems in the computer and relays and everything else.

JACK POUNDSTONE: We didn’t have relays in Poseidon and that’s why. We didn’t have flat packs.

CLINE FRASIER: We found contamination in the flat packs and they were the cleanest flat packs that could be bought, and still you have the contamination. The little silicon particles if they got into the right place would cause a block.

DAVE BATES: Solder balls.

CLINE FRASIER: No, these were silicon. The solder balls were in the relays. This would cause a hiccup from the computer which is not too good. That got sorted out through attention to cleaning the sinter around the vibration screen. Then maybe in ’68 or something like that, one of the guys at Autonetics had a job like yours. He would come around to see the NASA folks in Houston. We were talking and I asked him about the Minuteman II and he said, "I really shouldn’t tell you this but, I think it was last nine shots, we had seven failures. And these were the first nine shots. We had seven failures." I said, "My God, what happened?" He said, "Well, it’s up to staging. The thing stages, and the computer goes crazy and it blows up."

From that conversation, I told him what we were doing on Apollo, and what you guys had found out, and I expected the way things go that that would just totally die. And it wouldn’t get through the system. Apparently this was a real crisis at Autonetics, and the next step was they came to Raytheon, but Raytheon screened their modules, taught them how to screen and that's what got the Minuteman II program back online.

ED BLONDIN: A case in point though. That never could have happened on Apollo, where you could have seven out of nine failures. It kept everybody focused.

HERB BRISS: Well, it’s that man on board stuff again.

JACK POUNDSTONE: In my mind, as much as I hate to admit it, I think in that issue of the contamination in the flat packs we were all at fault there. We never thought about weightlessness.

ELDON HALL: Oh, yes we did. Starting with what do we do with it here sitting on the earth? I was very concerned about what is going to happen to those particles.

DAVE BATES: Oh, what was the one with the solder ball?

ELDON HALL: Apollo 14.

DAVE BATES: No, no, this was inside a flat pack.

ELDON HALL: It was in a relay. Apollo 12.

DAVE BATES: When they sealed the thing, North American had a problem. When they sealed a flat pack, they had a little solder ball on the top of it. But when they went into vibration, the solder ball fell off.

JACK POUNDSTONE: Oh, that's in a hybrid. You’re talking about solder hybrids.

ELDON HALL: In Apollo 12, the main panel DSKY at the launch pad signaled what was normally the test for detecting these shorts. All eights on the DSKY. They were just about ready to launch and it signaled all eights several times. We proved there was some sort of contamination in those relays and they all agreed with us. Yet that thing flew without any problem. So it sort of answered the question, are these things going to fool around?

JACK POUNDSTONE: What we didn’t do, though, was investigate passivation of some connector surfaces back in those days.

ELDON HALL: Not seriously, no.

JACK POUNDSTONE: That’s right. Today, that's a standard in the industry. We needed it back in Apollo.

DAVE HANLEY: And the particles got a static charge, and then would stick to things.

JACK POUNDSTONE: I know, but if they were passivated… We had unpassivated surfaces. You know.

DAVE HANLEY: You can contaminate the surface pretty easily, too.

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