TWO MAGNIFICENT FLYING MACHINES
But in April 1967 these machines were essentially strangers to me. How were they designed? How were they built and tested? What were their strengths and their weaknesses? Above all, what flaw in their design had caused the fire, and what other flaws lurked in their complexity?First there was the command and service module -the CSM- collectively a single spacecraft, but separable into two components (the command module and the service module) for the final minutes of reentry. It was built by North American Rockwell in Downey, California, a place which would become one of my many "homes" for the next 27 months. The command module was compact, solid, and sturdy, designed with one overriding consideration: to survive the fiery heat of reentry as it abandoned the service module and slammed back into the atmosphere at the tremendous speed of 25,000 miles an hour. It was a descendant of Mercury and Gemini, but its task was much more difficult. The speed of reentry from the Moon is nearly one and one-half times as fast as returning from Earth orbit; to slow down from that speed required the dissipation of great amounts of energy. In fact, there is enough energy at reentry to melt and vaporize all the material in the command module several times over, so the spacecraft had to be protected by an ablative heat shield that charred and slowly burned away, thereby protecting all that it surrounded. The command module was also crammed with equipment and subsystems; and of course three men lived in it for most of the lunar journey, and one of them for all of it. It was cone-shaped, with a blunt face for reentry; it was 11 feet long, 13 feet in diameter, and weighed 6 tons.
The service module was the quartermaster of the pair. It carried most of the stores needed for the journey through space; oxygen, power-generation equipment, and water as a byproduct of power generation. More than that, it had a propulsion system bigger and more powerful than many upper stages of present launch vehicles. It made all the maneuvers needed to navigate to the Moon, to push itself and the lunar module into lunar orbit, and to eject itself out of orbit to return to Earth. The service module was a cylinder 13 feet in diameter and 24 feet long. Fully loaded it weighed 26 tons.
Then there was the lunar module (LM, pronounced LEM, which had actually been its designation - for lunar excursion module - until someone decided that the word "excursion" might lend a frivolous note to Apollo). LM was the first true spaceship; it was hidden in a cocoon during the launch through the atmosphere because it could operate only in the vacuum of space. Built by Grumman in Bethpage, New York (another of my many homes away from home), it was somewhat flimsy, with paper-thin walls and spindly legs. Its mission was to carry two explorers from lunar orbit to the surface of the Moon, provide a base for them on the Moon, and then send its upper half back into lunar orbit to a rendezvous with its mother ship, the CSM. Designed by aeronautical engineers who for once did not have to worry about airflow and streamlining, it looked like a spider, a gargantuan, other-world insect that stood 23 feet tall and weighed 16 tons. When Jim McDivitt returned from Apollo 91, LM's first rnanned flight, he gave me a photograph of his Spider in space, with this caption: "Many thanks for the funny-looking spacecraft. It sure flies better than it looks."
These were the Apollo spacecraft: two machines. 17 tons of aluminum, steel, copper, titanium, and synthetic materials; 33 tons of propellant; 4 million parts, 40 miles of wire, 100,000 drawings, 26 subsystems, 678 switches, 410 circuit breakers.
To look after them there was a brand-new program manager who would have to leap upon this fast-moving train, learn all about it, decide what was good enough and what wasn't, what to accept, and what to change. In the meanwhile, the clock ticked away, bringing the end of the decade ever closer.
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