Preparing the Apollo Missions

by Thomas Wm. Hamilton

In 1963, I was very unhappy with my job. I was working for a well-known computer manufacturer and had been told I would work in Manhattan, enabling me to continue my grad school career. But my sixth day on a job I economically needed, I was told I would be in Poughkeepsie, New York, too far away for me to attend classes.

I let everyone know how unhappy I was, and someone passed my name along to Jerry Cook, an engineer at Grumman Aircraft, who was recruiting people to work on a contract they had recently received to build the Lunar Excursion Module, intended as the spacecraft to carry the first people to the Moon.

Cook phoned me, and asked if it was correct that I had an educational background in astronomy. I explained it was the graduate program I hoped to complete, and my undergraduate degree was in astronomy and German. His next question asked if I would be interested in working on the Apollo Project. I considered the idea for perhaps as long as a nanosecond and replied, “I can afford an arm and both legs to work on it.” He laughed and said, “I guess you’re interested.”

After an interview in Bethpage, Grumman’s headquarters, I was called back for a session with their security office. I filled out a form of four 8 × 14 pages, two columns each page, listing organizations they wanted to know if I or any family member was now or had been a member of. The bottom of the last page asked the same for any organization not listed that preached or advocated the violent overthrow of “the government,” with threats of civil and criminal penalties for lies or omissions. I dutifully wrote in that I had relatives who had indeed acted to violently overthrow the government; they had fired on the King’s troops in April 1775 as they marched towards Bunker Hill.

This disturbed the head of Security, who asked me to delete it “because it would cause trouble.” I asked if it would cause him trouble. He said no, and added, “It’s on your head, dammit, go ahead.”

I got the job despite my subversive fourth- and fifth-times great grandfathers and was assigned to a group called “LEM Dynamics.” The name was later changed to “LM Dynamics,” when NASA decided “Excursion” sounded too frivolous. The Dynamics group included about forty men — this was 1963, after all — and three secretaries, one of whom claimed to have worked as a Playboy Bunny.

I was the only one with an astronomy background. The rest included a couple of draftsmen, computer programmers, a mathematician, and a variety of engineers. The boss, Ross Fleissig, had been a long-time member and sometimes officer in the American Rocket Society.

Two early incidents stick in my mind. One fellow had plotted on ordinary graph paper the altitude of the initial planned Earth orbit of the Apollo spacecraft and was surprised it was not a flat line. I explained elliptical orbits and how they transfer onto graph paper.

The second incident had a number of engineers come complaining to me as the only local representative of the astronomical community that the Moon’s distance was not known to an accuracy of better than one mile. My response was that if the spacecraft would be flying about 240,000 miles, having a one-mile difference meant their tolerances were too tight.

What about those secrets the Security office had so diligently protected? The Saturn 5 launch rocket had quite a few secrets, but it was being designed and built in California by North American Rockwell, and I never got near it or its secrets.

Two secrets I did get close to were the planned date for the first manned landing and the communications frequencies. The original date of May 1967 was lost due to the Apollo 1 fire. And the radio frequencies NASA would use for communications with the astronauts were secret because, if published, it was feared every person on Earth with a ham radio would jam the airwaves trying to talk to them.

I found the engineers, lacking a proper education, had invented their own vocabulary. I heard constant reference to something called the “central angle,” and after a couple weeks finally asked for an explanation. One of the engineers put on his most gracious face and deigned to explain. With seconds, I said, “You mean the true anomaly!”

I had to explain to him and some eavesdropping engineers that astronomers had been dealing with this since Kepler’s day, over 300 years earlier. I wound up giving a brief impromptu class to bring them up to date on ordinary terminology, but they did invent one pair of new terms: pericynthion and apocynthion. These were closest and furthest points in an orbit around the Moon, based on an ancient Greek name for the Moon goddess.

My main job for the three years on Apollo was determining a back-up technique for lunar orbit rendezvous, radar accuracy requirements for the on-board radars during the return of the LM from the Moon to the orbiting CSM (Command and Service Module), fuel usage for the RCS (reaction control system), and a few other minor issues.

Calculations were done mostly on an IBM 7094 computer, only recently upgraded from a 709. Materials were sent to a central computer room and came back the next day. A small IBM 1620 sat near us and was available all the time, but it could not handle six degree of freedom problems.

An analog computer was also involved. On another, older Grumman building, the roof bore a large blue sphere. The inside had been adapted for a “full mission simulator” that astronauts were expected to use in training. But first, select Grumman employees were sent to test it and themselves.

Someone decided my work on the planned lunar orbit rendezvous of the LM and CSM made my flying the simulator a good idea. It was truly impressive, with a view of a shrinking lunar surface as I ascended into space to link up with the CSM. I felt embarrassed when the control panel showed I had rammed into the CSM at 19 feet per second, when the limit was under 10 fps. But I was told that most people missed rendezvous and had the LM wander off into lunar orbit, while a few crashed back on the Moon. I was congratulated for an excellent first — and only — flight.

By the time the first landing took place, I was working at Viewlex, writing canned shows for their Apollo model planetarium. For the landing, I bought my first television and held a three-day party, attracting a couple of dozen friends, one of whom brought his own TV. We were always tuned to two different networks, switching if one dared carry a commercial. My only disappointment was that the broadcast from space was not interrupted by an alien voice announcing we had qualified for junior membership in the Galactic Federation.