Apollo Expeditions to the Moon|
WHEN THE RED LIGHT LIT UPIt was remarkable that every manned Apollo launch lifted off exactly on schedule, up to the last one. (Apollo 14's forty-minute delay was due to weather.) But Apollo 17, the only night launch, was delayed 2 hours and 40 minutes, until 12:33 a.m., because of the failure of an automatic countdown sequencer in the ground equipment. The way we had the launch set up was that the last three-minute period in effect was a series of automatic commands, all done by a timer. If you didn't get through a certain gate in the automatic sequencer the next command would not be given. This protected us against a faulty liftoff.
This is what the term "terminal sequence" meant, which took a great deal of check-out time in the months preceding launch. When we got down to 30 seconds before lift-off, the indication of pressurization for one of the propellants in the S-IVB stage hadn't registered, so the sequencer stopped the count. The red light on the overhead indicator in the firing room lit up. The engineer monitoring that read-out on the strip chart told us the S-IVB was not pressurized. The ladder in the sequence wasn't met, so we got a cut-off at 30 seconds.
The team went through a back-out act, as they had practiced, the arming command was withdrawn, the on-board batteries were taken off line, the radio-frequency transmitters turned off, and within three or four minutes the space vehicle had been returned to a status where we could safely hold. Everything was done very coolly, very gingerly. Gene Cernan, the commander of the flight, said later that he kept his hand - very tightly - on the abort switch, "because you never know". But once again the launch escape tower went unused.
The problem turned out to be a faulty diode in the terminal sequencer. Among the hundreds of commands given in sequence, one was not forthcoming, so everything stopped - which is one of the marvels of Apollo. At this late date in the program nobody batted an eye, including Walter J. Kapryan, the able engineer who had succeeded me as launch director when I went to Washington as Apollo Program Director three years earlier.
No story about the Cape - Canaveral, then Kennedy, then Canaveral again - would be complete without a mention of the visitors. By the time the Apollo program ended in 1972 we had attracted more than 6 million of them, and that doesn't count people who lined the roads and watched the lift-offs (there were a million of those, it was estimated, for Apollo 11). We had VIP visitors in a steady stream - Presidents of the United States, members of the Supreme Court, members of Congress, almost any prominent person you could mention.
We had leaders from many countries - I recall the Shah of Iran, King Hussein of Jordan (he was a jet pilot), the King of Afghanistan, King Baudoin of Belgium, Haile Selassie of Ethiopia, Chancellor Erhard of Germany, and President Radhakrishnan of India, who had been a professor of philosophy at Oxford. Other visitors included foreign ministers and cabinet members from many countries. We talked to most of them in informal sessions, explaining as best we could the mysteries of spaceflight. The one visitor who impressed me most came in November 1963, and we briefed him on a Saturn-Apollo unmanned mission due to fly in January - which would be the first Saturn I to carry two stages (with a total of 14 engines, still the record for launch vehicles). He promised to come back for the launch if he possibly could. But he never made it because he was assassinated in Dallas six days later.