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NASA Historical Reference Collection, NASA History Office, NASA Headquarters, Washington, DC.

History of The Accident

1. Events From Initiation Of Fabrication Until The Initiation Of The "Plugs Out" Test

Spacecraft 012, assigned to Mission AS-204, was built at North American Aviation, Inc., Space and Information Systems Division, Downey, California. Enclosure 1 shows sketches of the complete space vehicle, the spacecraft and the Command Module. Fabrication was begun in August 1964 and the basic structure was completed in September 1965. While the structure was being fabricated, each component of every subsystem was subjected to acceptance tests and subsystems were assembled. During this period a series of Preliminary Design Reviews were held between November 1964 and January 1965. Installation and final assembly of subsytems into the Command Module took place between September 1965 and March 1966. Critical Design Reviews were held during February and March 1966. Checkout of all subsystems was then initiated followed by integrated testing of all spacecraft subsystems. A series of reviews of the spacecraft and checkout was held during the checkout and integrated testing process. A two-phase Customer Acceptance Readiness Review was conducted by NASA at Downey in conjunction with NAA in July and August 1966. After the August review NASA issued a Certificate of Flight Worthiness and authorized the spacecraft to be shipped to the John F. Kennedy Space Center (KSC), Florida. The Certificate included a listing of open items and work to be completed at KSC.

The Command Module was received at KSC on August 26, 1966. It was mated with the Service Module in the altitude chamber at KSC early in September 1966 and alignment, subsystems and system verification tests and functional checks were performed. Many open design change orders were completed and various malfunctions were noted and corrected. The first combined systems tests were begun on September 14 and completed on October 1, 1966. Several malfunctions were noted and correction of some these was deferred to a later date.

A Design Certification Review was held at NASA Headquarters during September and October 1966. This detailed review was conducted by a Board chaired by the Associate Administrator for Manned Space Flight. Board Members were Office of Manned Space Center Directors. This Board issued a Design Certification Document on October 7, 1966 which certified the design as flightworthy, pending satisfactory resolution of listed open items.

After the combined systems tests were completed at KSC in the altitude chamber, the first manned test in this facility was performed. This test was conducted in air at sea level pressure and was made to verify total spacecraft system operation. The test was initiated on October 10 and discontinued on October 11 to replace bent umbilical pins. The test was begun again on October 12 and completed on October 13. On October 14 and 15, an unmanned test was performed at altitude pressures using oxygen to verify spacecraft system operation under these conditions before a manned altitude test was run. The manned test (with the flight crew) was initiated on October 18 but was discontinued after reaching a simulated altitude of 13,000 feet because of the failure of a transistor in one of the inverters in the spacecraft. The inverter was replaced and the test was completed on October 19. A second manned altitude test (with the backup crew) was initiated on October 21 but it was discontinued when a failure occurred in an oxygen system regulator in the spacecraft Environmental Control System. This regulator was removed and found to have a design deficiency. While redesign was being accomplished various spacecraft work items were completed.

On October 27 the Environmental Control Unit was removed and returned to the factory for a design change to the water/glycol evaporator.

During this period a propellant tank had ruptured in the Service Module of Spacecraft 017 at Downey. Therefore, it was decided that the tanks on the Spacecraft 012 Service Module should be checked by special testing at KSC. In order to conduct this testing in parallel with further checking of the Spacecraft 012 Command Module was removed from the altitude chamber. The Service Module was later removed for tests related to the propellant tanks. The Service Module and Command Module were reinstalled in the altitude chamber and ECU was installed. A water/glycol leak developed in the ECU, and it was again returned to the factory for further examination of the leak problem. It was returned on December 14, 1966.

Also, during this period on December 21, 1966 the Apollo Program Director conducted a Recertification Review which closed out the majority of the open items remaining from previous reviews.

After the Command and Service Modules were reinstalled in the altitude chamber and testing in the chamber was resumed. The sea level and unmanned altitude tests were conducted on December 27 and 30.

It should be noted that this final manned test in the altitude chamber was very successful with all spacecraft systems functioning normally. At the post-test debriefing the backup flight crew expressed their satisfaction with the condition and performance of the spacecraft.

It should also be noted that in the altitude chamber tests the Command Module was pressurized with pure oxygen four times at pressures greater than 14.7 psia for a total time of 6 hours and 15 minutes. The total time was about 2 1/2 times longer than the time the Command Module was pressurized with oxygen during the test which was in progress when the accident occurred.

The Command Module was removed from the altitude chamber on January 3, 1967 and the spacecraft was mated to the launch vehicle on January 6 at Launch Complex 34. Various tests and equipment installations and replacements were then performed.

The system was determined to be ready for the initiation of the Plugs-Out Test on January 27, 1967.

Of the many events which took place at KSC subsequent to the arrival of the spacecraft a few stand out as possible indications of deficiencies in the program and some appear to have possible relation to the fire.

The events that possibly may be related to the fire are those concerned with the occasions when water/glycol spillage or leakage from the Environmental Control System was noted. This may be of significance in that water.glycol coming into contact with electrical connectors can cause corrosion of these connectors. Dried water/glycol on wiring insulation leaves a residue which is electrically conductive and combustible. Of the six recorded instances where water/glycol spillage or leakage occurred (a total of 90 ounces leaked or spilled is noted in the records) the records indicate that this resulted in wetting of conductors and wiring on only one occasion. Action was taken to clean the water/glycol from the connectors and wiring on this one occasion. There is no evidence which indicates that damage resulted to the conductors or that faults were produced on connectors due to water/glycol which contributed to the fire. If the cleaning was inadequate, residue would have remained on the wires. Also, undetected wetting could have occurred, which would leave a residue. Small quantities of water/glycol were found in the Command Module after the fire. This, however, could have been due to water/glycol line breakage which is known to have occurred during the fire. And while water/glycol and its residue may have contributed to the spread of the fire there is no positive evidence that residue was related to the ignition of the fire.

The number of open items at the time of shipment of Command Module 012 was not known. There were 113 significant Engineering Orders not accomplished at the time Command Module 012 was delivered to NASA; 623 Engineering Orders were released subsequent to delivery. Of these, 22 were recent releases which were not recorded in configuration records at the time of the accident.

The effort and rework required on Spacecraft 012 at KSC was greater than that experienced on the first manned Gemini spacecraft. However since the Apollo Spacecraft are considerably more complex than Gemini Spacecraft this does not necessarily indicate that the quantity of problems encountered was excessive. There is, however, an inference that the design, qualification and fabrication process may not have been completed adequately prior to shipment to KSC.

Another item should be noted when considering the problems that were found at KSC including some of the problems encountered in the Plugs-Out Test prior to the fire. The prime purpose of all tests conducted prior to launch is to verify and demonstrate that the space vehicle ground support equipment, procedures and personnel are all ready for flight operations. Many of the tests involve a "first time" operation particularly in an overall sense. Therefore, inherent in the verification process is the likelihood that faults will be found in procedures and in equipment. This Plugs-Out Test had not been classified as hazardous because only those tests involving fueled vehicles, hypergolic propellants, cryogenic systems, high pressure tanks, live pyrotechnics or altitude chamber tests were routinely classified as hazardous.

Description of Test Sequence And Objectives | 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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