The erection of the S-IB stage and the dummy stages for the S-IVB and instrument unit marked the start of LC-34 facility tests on 18 August 1965. Although the mating went well, the launch team soon fell behind schedule. Hans Gruene reported a four-day lag the following week, attributing most of the delay to faulty electrical support equipment from Huntsville. He listed among the shortcomings missing connectors, cables improperly marked, and schematics that did not reflect engineering changes already accomplished.5 Similar problems threatened in early September to postpone the start of tests on the ground equipment test sets. More than 250 power cables had not arrived. About 100 GE cables were of the wrong length. Gruene also singled out computer problems, an area that would plague Launch Vehicle Operations throughout the 201 mission. The shortage of spares was also critical. A power supply failure on the 26th had necessitated the air delivery of a new component from California. Computer breakdowns during the test of the ground equipment test sets could cause a day-for-day slip in the schedule. Delays in Marshall's breadboard* testing of the RCA 110A operating program could also impact the checkout.6
The wet test in September disclosed some problems in LC-34's new propellants system. Hydrogen did not flow from its storage tank during the first H2 "cold shock" test. When no mechanical block could be found in the valves, lines, or filter, the obstruction was blamed on frozen nitrogen. The gas had leaked into the hydrogen system through a hand valve during the nitrogen pressurization test. The launch team also had trouble loading the S-IVB auxiliary propulsion system.** The surprisingly slow flow rate of the hypergolic oxidizer, coupled with a thunderstorm, left no time for the flow test of the fuel. As Launch Vehicle Operations planned to remove the dummy stage the following day, the second half of the hypergolic loading was postponed until after the erection of the live stage.7
Another highlight of the facilities test was the replacement of an S-IB fuel tank. The tank had been damaged during a load test, and repressurization left numerous wrinkles in its skin. Although a Chrysler crew subjected the tank to above-normal pressures without mishap, Marshall representatives wanted a replacement. The new fuel tank arrived from Michoud, Louisiana, on 24 September and was installed in eight hours on the 29th. This delayed erection of the S-IVB stage by two days, but numerous breakdowns in the RCA 110A computer had already thrown the tests 12 days behind schedule.8
* Breadboard means an assembly of circuits or parts used to prove the feasibility of a device or system. Huntsville used breadboards as a design tool (those for Saturn circuitry occupied a half-dozen large rooms). The breadboards were kept in the same configuration as the vehicle and ground support equipment. When a problem arose, Huntsville engineers verified any proposed solution on the breadboard before KSC applied it to the flight equipment.
** The auxiliary propulsion system provided attitude control for the S-IVB stage and payload during the coast phases of flight.