Astronauts and Automation

As eventual users of the Apollo guidance system, the astronauts had values, opinions, and goals that complicated the programmers' work. Most of the IL staff remember the early astronauts as resistant to electronics, computers, and automation. They were used to a world where electronics routinely failed. ''The fact that we were going to do things in a digital system, an inertial system,'' Cline Frasier recalled, ''they absolutely believed to their core that stuff wasn't going to work.''38 Sensitive about their level of activity in the spacecraft, astronauts found it difficult to accept the idea that the digital computer would be even partially in control.

As Alonso remembered it, the astronauts saw the computer like a calculator, a disposable appendage to the flight. ''Of course we'll shut the computer off as soon as we're up there'' he was told (indeed the early plans did involve shutting the system down between maneuvers).39 Other times the astronauts wanted to approve, step by step, every move the computer made. Such a desire, of course, was wildly impractical with a computer running thousands of instructions per second and would lead to an impossibly high workload. Similarly, the users wanted direct control of the systems— right down to the valves themselves, asking, for example, for hand throttling of the LM's descent engine.40 Nonetheless, the astronauts were not being reactionary, just hard-headed about which systems they were willing to stake their lives on. Lickly remembered his first lecture to the ''new nine'' on automatic control of reentry: ''I was just overwhelmed by the smart questions. Neil Armstrong was all over it. . . . They knew the right questions to ask. They weren't Luddites.''41 Eventually, the word came down from NASA that the astronauts could suggest changes and provide input to the systems design, but that they could not dictate the basic controls philosophy.

Battin remembers a story he told to astronaut and Apollo 12 Commander Pete Conrad: ''One day an airliner was on the field, and wasn't able to take off. An announcement came over the intercom, 'Sorry passengers, we can't take off, there is an indication of a problem with the airplane. We've got to replace a piece of equipment and it's going to be very difficult and take many hours.' Just half an hour later, another voice announced that the flight was ready to go. One of the passengers asked, 'I guess it was easier than you thought to replace that piece of equipment.' The airline representative replied, 'No, we replaced the pilot.''' Battin remembered Conrad being impressed by the story and repeating it to others.42 The message: if the astronauts weren't happy with the automation, there were plenty of other people willing to go.

IL engineers gave regular courses about their systems to astronauts and other NASA personnel. In general, they found the astronauts disinterested in the computers, or even in the guidance per se. Research engineers at the IL had a habit of teaching the fundamental principles, but the crews wanted operational techniques and checklists. Indeed, much of the IL's training proved more academic and theoretical than the astro nauts could absorb. Michael Collins found it sufficiently off-putting to record his response to one course in his diary: ''This course was designed for someone who is going to either (a) build a better computer, or (b) repair and replace components of the existing computer. It was not a course for the pilot, who needs to know how to operate the computer and how to detect malfunctions.''43 Collins both rejected in-flight repair and made the point that the IL lacked experience in communicating with operators.

Still, astronauts made numerous suggestions to the IL engineers, most of them fairly concrete. For example, they wanted velocity units displayed in feet per second, even though the AGC used metric units internally. The software thus did a whole series of conversions between metric and English units for the user interface. Procedures and even trajectories were modified to allow the astronauts to monitor, and possibly interrupt, the automatic sequences.44 A PRO button, for ''proceed,'' allowed the astronauts to approve major actions (like firing the engines) before the computer commanded the hardware.

Difficult problems still arose, like the ''attitude indicator'' in the spacecraft, the primary display of which way the vehicle was pointing. Pilots were used to the artificial horizon in aircraft, a gyro-driven display that maintained orientation to the vertical, with a dark region on the bottom representing the earth and a light-blue region above representing the sky. In the spacecraft, this unit needed to be a ball, because of the wide range of possible attitudes. It became formally known as the ''flight director attitude indicator'' (FDAI), but colloquially as the ''eight ball.''

But how should the eight ball be oriented? In aircraft, a gyroscope drove the artificial horizon directly, which seemed elegant to the IL engineers, who proposed driving the Apollo eight ball off one of the gimbals in the inertial platform;like the platform itself, the ball would then be fixed in inertial space (i.e., in relation to the stars). This solution did not appeal to the astronauts, however, because it meant that as the spacecraft orbited the earth, the ball would seem to rotate as well and would not track the horizon. As an alternative, the ball could track the horizon, the ''local vertical'' (on earth or the moon), but that also created problems. A ball tracking local vertical would be essentially useless, for example, as the spacecraft pointed skyward on the launch pad and during launch before it pitched over toward orbit. A similar set of problems, in reverse, affected decisions on the eight ball for the LM. The astronauts got their way because they would have to use it, but it offended the IL engineers' sense of elegance and accuracy. ''I do think that somehow they are being too much dominated by their experience in flying airplanes,'' Hoag said at the time, ''to go over this [flat] plane which is the earth surface, rather than going out and away and trying to go between this earth and the moon.''45

Another critical question: should the computer allow the astronauts to do something dangerous with the spacecraft? Initially, IL programmers put in a series of caveats and constraints. Jim Miller remembered Alan Shepard objecting to this approach on his 1962 visit. ''Take out all those inhibitions ...if we want to kill ourselves, let us. It may involve saving ourselves,'' Shepard said. ''Of course he was right,'' Miller remembered, ''and it made the software a lot easier.''46 Yet Hamilton fought hard to get user-error-checking in the code. ''We were very worried that what if the astronaut, during mid-course, would select the pre-launch [program] for example? Never would happen, they said.'' (But exactly that did happen on Apollo 8.)47

NASA insisted these were the most expert, highly trained users in the world. Of course the astronauts were very well trained, and experts in their systems. But they also got very tired, and building performance limits in the software could mitigate the effects of fatigue. Astronauts swore to Lickly they were going to fly the reentry manually, without using his automated program (this before Gemini's success with automated reentry). ''As far as I know, none of them ever touched a manual stick,'' on reentry, Lickly remembered, for ''they were so beat'' after a two-week flight.''48

At the 1963 press conference, Hoag put the issue more colorfully, describing the computer as ''a young maiden who is asked something improper, and she'd also respond in that fashion. The computer, too, will not do things that it shouldn't.'' If an incorrect key or code were entered, the computer would signal ''operator error'' so the astronaut could try again.49 In the end, the software came up against the limits of memory usage, and most of the self-checks had to be eliminated anyway. It did, however, check basic keystrokes and allow astronauts to recover from keyboard errors, analogous to a modern ''escape'' key or ''undo'' function.

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