Source: This document taken from the Report of Apollo 204 Review Board
NASA Historical Reference Collection, NASA History Office, NASA Headquarters, Washington, DC.

Description of Test Sequence and Objectives

2. Events From Initiation Of The Plugs-Out Test Until The T-10 Minute Hold

The purpose of the Space Vehicle Plugs-Out Integrated Test, Operational Checkout Procedures (OCP) FO-K-0021-1, Spacecraft 012 is to demonstrate all space vehicle systems and operational procedures in as near a flight configuration as is practical and to verify their capability in a simulated launch. System verification is performed, an abbreviated final countdown conducted and a flight simulation made. All communication and instrumentation systems are activated and proper measurements are monitored at appropriate ground stations. At the start of the simulated flight, umbilicals are disconnected and the spacecraft is on simulated fuel-cell power.

Specific objectives of this test for Spacecraft 012 as stated in the Final Procedure Document were:
a) To verify overall spacecraft/launch vehicle compatibility and demonstrate proper function of spacecraft systems with all umbilicals and Ground Support Equipment disconnected.
b) To verify no electrical interference at the time of umbilical disconnect.
c) To verify astronaut emergency egress procedures (unaided egress) at the conclusion of the test.

The preliminary outline for this test procedure was written by North American Aviation, Inc. (NAA) in July 1966. The test procedure was reviewed and revised periodically over the next few months. In September the flight crew requested that emergency egress practice which was not in the original test outline be added. This addition was requested because a subsequent test, Countdown Demonstration, would involve a fully fueled Launch Vehicle and this latter test was identified as hazardous. This egress test was then added to the Space Vehicle Plugs-Out Integrated Test.

The first draft of the Procedure was issued on September 26, 1966. After informal review and revision a second draft was issued on October 19, 1966. After formal review by both NASA and NAA, and further revision the formally approved procedure was issued on December 13, 1966. This procedure was reviewed at KSC and operational and minor technical changes made. A major revision was issued at 5:30 p.m. EST on January 26, 1967 and 4 additional pages were issued at 10:00 a.m. EST on January 27, 1967.

The Plugs-Out Test was initiated on January 27, 1967 at 12:55 GMT (7:55 a.m. EST) when power was applied to the spacecraft for this test. After completion of initial verification tests of system operation the flight crew entered the Command Module. The Command Pilot entered at 18:00 GMT (1:00 p.m. EST) followed by the Pilot and Senior Pilot. The Command Pilot noted an odor in the Spacecraft Environmental Control System suit oxygen loop and the count was held at 18:20 GMT while a sample of the oxygen in this system was taken. This odor has been determined from subsequent analysis not to be related to the fire. The count was resumed at 19:42 GMT with hatch installation and subsequent cabin purge with oxygen beginning at 19:45 GMT. Communication difficulties were encountered and the count was held at approximately 22:40 GMT to troubleshoot the problem. Various final countdown functions were still performed during the hold as communications permitted. From 22:45 GMT until about 22:53 GMT the flight crew interchanged equipment related to the communications systems in an effort to isolate the communications system problem. This problem consisted of a continuously live microphone that could not be turned off by the crew. The live microphone condition was first noted by the test crew about 22:25 GMT and records indicate that the condition first occurred between about 20:57 GMT and 22:18 GMT. During the troubleshooting period problems developed in the ability of various ground stations to communicate with one another and with the crew. None of the communications problems appear to have had a direct bearing on the fire.

By 22:20 GMT (6:20 p.m. EST) all final countdown functions up to the transfer to simulated fuel cell power were completed and the count was held at T-10 minutes pending resolution of the communications problems.

History Of The Accident | Chronology From T-10 Minutes | Investigation And Analysis | Findings, Determinations And Recommendations


Updated February 3, 2003
Steve Garber, NASA History Web Curator
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