Space: Trial & Triumph

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On Launch Complex 34 of Cape Kennedy stood Saturn IB, the mightiest rocket the U.S. — and most likely the world — has ever known. The 224-ft.tall bird, with a fantastic initial thrust of 1,600,000 lbs. to hurl its 650-ton bulk into space, was ready for its first crucial test. Atop Saturn's nose sat the payload: the 33,800-lb. Apollo three-man command capsule and service module that will transport U.S. astronauts to the moon and back. If the U.S. is to achieve its goal by 1969, now was the time to start ironing out the bugs.

The flight plan called for a suborbital 5,500-mile flight downrange to Ascension Island in the South Atlantic. As it turned out, practically all the bugs were on the ground. The shot was delayed for 75 hours, while the kind of weather that Florida does not advertise locked the cape in clouds and rain. When the skies finally cleared, low pressure readings from a small nitrogen sphere that operates fuel valves delayed the lift-off for 31 hours; at one point, NASA control in Houston decided to scrub the mission, but technicians on the pad convinced Launch Director Kurt Debus that the pressure—though low—was sufficient to complete the mission. The rest was something for rocketeers to cheer about and a new eyeful for the millions who watched on television.

Roar & a Crackle. Its eight booster engines spitting a 150-ft. tail of flame, Saturn 1B burned for 2 min. 26 sec., at which point it was 35 miles up and moving at 5,400 m.p.h. Next came the tricky second stage, a single 225,000-lb.-thrust engine powered by an exotic combination of liquid oxygen (lox) and liquid hydrogen (LH2). While lox boils off at a difficult -290° F., LH2 boils at -423° F., thus requires extreme pressurization to keep cool. Moreover, in weightless space, LH2, like mercury, tends to gather into a ball or spin off into tiny globs; simply to feed the fuel from tank to engines, the second stage was equipped with three fast-burning rockets that exerted enough G force to start the LH2, flowing. All went smoothly, and after 7½ minutes of burn, Saturn was 170 miles up.

Critical to this and all future missions was the supersophisticated 3-ft.-high IBM instrument unit, packed with 3,900 lbs. of computers, monitors and guidance equipment so carefully contrived that the entire system was triply redundant. If one set of circuits disagreed with the other two, the system would take an instantaneous vote, with the majority ruling. In a series of programmed commands halfway through the 40-minute flight, the unit ordered itself and the second-stage engine to jettison.

Now the test turned to Apollo coasting through space at 15,000 m.p.h. Inside the 24-ft. spacecraft and its service module was virtually everything that will go to the moon—except the three astronauts, their couches and the Lunar Excursion Module (LEM), for which ballast had been substituted. At an altitude of 310 miles, a programmer—filling in for the astronaut pilot—ordered the Apollo's own 22,900-lb.-thrust engine to head the craft back to earth, increase its speed, then separate the module just before reentry.