ercise to a conclusion. Throughout the morning, however, most of the preparations went smoothly, with one group after another finishing checklists and reporting readiness.
After an early lunch, Grissom, White, and Chaffee suited up, rode to the pad (arriving an hour after noon), and slid into the spacecraft couches. Technicians sealed the pressure vessel inner hatch, secured the outer crew access hatch, and then locked the booster cover cap in place. All three astronauts were instrumented with biomedical sensors, tied together on the communications circuit, and attached to the environmental control system. Strapped down, as though waiting for launch, they began purging their space suits and the cabin atmosphere of all gases except oxygen--a standing operating procedure. (2)
STALKED BY THE SPECTRE
For almost a year, the Grissom crew had watched its craft go through the production line, test program, and launch pad preparations. After participating in a multitude of critiques, reading numerous discrepancy reports, and going through several suited trials in the spacecraft in altitude chambers at Downey and the Cape, Grissom's group had learned almost all the idio- syncracies of spacecraft 012. The astronauts knew, if not every nut and bolt, at least the functions of its 88 subsystems and the proper positions for hundreds of switches and controls inside the cockpit. They also knew that the environmental unit had been causing trouble. Indeed, Grissom's first reports on entering the cabin were of a peculiar odor--like sour milk. (3)
As all traces of sea-level atmosphere were removed from the suit circuit and spacecraft cabin, pure oxygen at a pressure of 11.5 newtons per square centimeter (16.7 pounds per square inch) was substituted. The crew checked lists, listened to the countdown, and complained about communications problems' that caused intermittent delays. The men could speak over four channels, either by radio or telephone line, but the tie-in with the test conductors and the monitors was complicated and troublesome. Somewhere there was an unattended live microphone that could not be tracked down and turned off. Other systems, Grissom's crew noted, seemed to be operating normally. At four in the afternoon, one shift of technicians departed and another came on duty.
Near sunset, early on this winter evening, communications problems again caused a delay, this time for ten minutes, before the plugs could be pulled. Thus, the test that should have been finished had not really started, and an emergency egress practice was still to come. The crew was accustomed to waiting, however, having spent similar long hours in trouble-plagued training simulators. About 6:30, Grissom may have been thinking about the jest he had played on Riley McCafferty by hanging a lemon on the trainer. (4)
Donald Slayton sat half a kilometer away at a console in the blockhouse next to Stuart Roosa, the capsule communicator. On the first floor of the launch complex, Gary W. Propst, an RCA employee, watched a television monitor that had its transmitting camera trained on the window of the command module. Clarence A. Chauvin, the Kennedy Space Center test conductor, waited in the automated checkout equipment room of the operations building, and Darrell O. Cain, the North American test conductor, sat next door. NASA quality control inspector Henry H. Rogers boarded the Pad 34 elevator to ride up to the clean room. There, at the moment, were three North American employees: Donald O. Babbitt, pad leader; James D. Gleaves, mechanical technician; and L. D. Reece, systems technician. Reece was waiting to pull the plugs on signal. Just outside on the swing arm, Steven B. Clemmons and Jerry W. Hawkins were listening for Reece to call them to come and help. All of these men and several others in the vicinity at 6:31 heard a cry over the radio circuit from inside the capsule: "There is a fire in here. (5)
Stunned, pad leader Babbitt looked up from his desk and shouted to Gleaves: "Get them out of there!" As Babbitt spun to reach a squawk box to notify the blockhou