January 27, 1967
Plugs Out Integrated Test initiated when power applied to spacecraft. 12:55
Following completion of initial verification tests of system operation, command pilot entered spacecraft, followed by pilot and senior pilot. 18:00
Count held when command pilot noted odor in spacecraft environmental control system suit oxygen. Sample taken. 18:20
Count resumed after hatch installed. 19:42
Cabin purged with oxygen. 19:45
Open microphone first noted by test crew. 22:25
Count held while communication difficulties checked. Various final countdown functions performed during hold as communications permitted. 22:40
From this time until about 23:53 GMT, flight crew interchanged equipment related to communications systems in effort to isolate communications problem. During troubleshooting period, problems developed with ability of various ground stations to communicate with one another and with crew. 22:45
Final countdown functions up to transfer to simulated fuel cell power completed and count held at T-10 minutes pending resolution of communications problems. For next 10 minutes, no events related to fire. Major activity was routine troubleshooting of communications problem. All other systems operated normally during this period. 23:20
First indication by either cabin pressure or battery compartment sensors of a pressure increase.
23:21:11
Command pilot live microphone transmitted brushing and tapping noises, indicative of movement. Noises similar to those transmitted earlier in test by live microphone when command pilot was known to be moving. 23:30
No voice transmissions from spacecraft from this time until transmission reporting fire. 23:30:14
Slight increase in pulse and respiratory rate noted from senior pilot. 23:30:21
Data from guidance and navigation system indicated undetermined type of crew movement. Gradual rise in oxygen flow rate to crew suits began, indicating movement. Earlier in Plugs Out Integrated Test, crew reported that an unspecified movement caused increased flow rate. 23:30:24
Senior pilot’s electrocardiogram indicated muscular activity for several seconds. 23:30:30
Additional electrocardiogram indications from senior pilot. Data show increased activity but were not indicative of alarm type of response. More intense crew activity sensed by guidance and navigation system. 23:30:39
Crew movement ended. 23:30:44
All of senior pilot’s biomedical parameters reverted to “rest” level. 23:30:45
Variation in signal output from gas chromatograph. 23:30:50
Significant voltage transient recorded. 23:30:54.8
Command pilot microphone noises ended. 23:30:58.6
Oxygen flow rate reached limit of sensor. 23:30:59
Additional spacecraft movement noted 23:31:00
First voice transmission ended. 23:31:10
Fire broke from its point of origin. Evidence suggests a wall of flames extended along left wall of module, preventing command pilot, occupying left couch, from reaching valve which would vent command module to outside atmosphere. Original flames rose vertically and spread out across cabin ceiling. Scattering of firebrands of molten burning nylon contributed to spread of flames. It was estimated that opening valve
would have delayed command module rupture by less than one second. 23:31:12
First verbal indication of fire reported by crew 23:31:04.7
Cabin pressure exceeded range of transducers, 17 pounds per square inch absolute (psia) for cabin and 21 psia for battery compartment transducers. Rupture and resulting jet of hot gases caused extensive damage to exterior. 23:31:16
Beginning of final voice transmission from crew. Entire transmission garbled. Sounded like, “They’re fighting a bad fire—let’s get out. Open ‘er up.” Or, “We’ve got a bad fire—let’s get out. We’re burning up.” Or, “I’m reporting a bad fire. I’m getting out.” Transmission ended with cry of pain, perhaps from pilot. 23:31:16.8
Command module ruptured, start of second stage of fire. First stage marked by rapid temperature rise and increase in cabin pressure. Flames had moved rapidly from point of ignition, traveling along net debris traps installed to prevent items from dropping into equipment areas. At same time, Velcro strips positioned near ignition point also burned. 23:31:19.4
End of final voice transmission. 23:31:21.8
All spacecraft transmissions ended. Television monitors showed flames spreading from left to right side of command module and shortly covered entire visible area. Telemetry loss made determination of precise times of subsequent occurrences impossible. 23:31:22.4
Third stage of fire characterized by greatest conflagration due to forced convection from outrush of gases through rupture in pressure vessel. Swirling flow scattered firebrands, spreading fire. Pressure in command module dropped to atmospheric pressure five or six seconds after rupture. 23:31:25
Command module atmosphere reached lethal stage, characterized by rapid production of high concentrations of carbon monoxide. Following loss of pressure, and with fire throughout crew compartment, remaining atmosphere quickly became deficient in oxygen and could not support continued combustion. Heavy smoke formed and large amounts of soot deposited on most spacecraft interior surfaces. Although oxygen leak extinguished most of fire, failed oxygen and water/glycol lines supplied oxygen and fuel to support localized fire that melted aft bulkhead and burned adjacent portions of inner surface of command module heat shield. 23:31:30
Fire apparatus and firefighting personnel dispatched. 23:32
Attempts to remove hatches. 23:32:04
Pad leader reported that attempts had started to remove hatches. 23:32:34
Hatches opened, outer hatches removed. Resuscitation of crew impossible. 23:36
Pad leader ascertained all hatches open, left White Room, proceeded a few feet along swing arm, donned headset and reported this fact. 23:36:31
Firefighters arrived at Level A-8. Positions of crew couches and crew could be perceived through smoke but only with great difficulty. Unsuccessful attempt to remove senior pilot from command module.
23:40
Doctors arrived. 23:43
Photographs taken, and removal efforts started. 28 Jan 1967 00:30
Removal of crew completed, about seven and one-half hours after accident. 07:00
Command module 014 shipped to KSC to develop disassembly techniques for selected components prior to their removal from command module 012. 01 Feb 1967
Disassembly plan fully operational. 07 Feb 1967
Command module moved to pyrotechnics installation building at KSC, where better working conditions were available. 17 Feb 1967
Disassembly of command module completed. 27 Mar 1967
What caused the Disaster
As with most engineering disasters, the determination of the exact cause of the disaster was not easy. The Apollo 1 mission to this day still remains a mystery. The specific initiator of the fire has not yet been determined, and probably never will be. However, after investigation, a number of factors that signifacntly contributed to the disaster were determined. The fire began because of an electical short, it spread quickly because of the volatile atmospheric conditions and the presence of combustible materials inside the module. The hatch design and NASA's management of the Apollo program may have also been contributing factors.
Electrical Components
In the Apollo 204 spacecraft, many problems occurred with the electrical wiring. Teflon, has an excellent fire resistance and was therefore chosen as the covering for the wiring in the spacecraft. The specific type used for the craft was easily damaged or penetrated by abrasion. If this wiring experiences penetration by a metal structure (namely spacecraft components) a short is created at the point of conductor contact. Tests performed in highly pressurized atmosphere indicate that sparks blown from an arc can ignite combustible materials that are a short distance away from that arc. Taking this into consideration, it is quite feasible that the many arcs located by investigators on the spacecraft could have been the initiator of the fire.
Electric power distribution malfunctions in the Apollo 204 module were also related to the Environment Coolant System leakage. RS-89 was the coolant the leaked, which is a mixture of 62.5 percent ethylene glycol, 35.7 percent H20, and 1.8 percent stabilizer and corrosion inhibitor. This mixture is not highly combustable, however leakage and spillage of this fliud does present a threat. The water in this fluid evaporates much faster than the ethylene glycol. This results in a salt formation that does not evaporate and which is highly combustable. Furthermore, the residue from RS-89 is electrically conductive, therefore contact with uninsulated wire would result in current exposure to the internal atmosphere. It was proved in laboratory tests that this coolant provides an mechanism to ignite a fire.
Spacecraft Atmosphere
The high pressure and concentration levels of oxygen gas largely contributed to the dispersion of the fire. During the initail stages of the fire oxygen levels were reported to be at saturated levels which may have prompted the spread of the fire. The initial flow rate increase was probably due to crew movement which normally results in increased leakage to the cabin.
Combustible Materials
The fire moved rapidly from the point of ignition, traveling along the Raschel net debris traps which were installed in the Command Module (CM) to prevent items from dropping into equipment areas during tests. These nets were made mainly of nylon, and were thus highly combustible. Since these nets ran along large sections of the CM they generated firebrands which scattered, igniting more materials. NASA was aware of this undesirable property, but not anticipating a fire in the test runs, allowed them to be used on the ground but not during space flight.
Hatch Design
The main exit from the Command Module was through inner and outer hatches. The hatch design for the Apollo 1 spacecraft was not a cause of the disaster, but it had a large impact on the outcome. With this particular design three hatches were installed. The outermost hatch (the Boost Protective Cover (BPC)) covers the Command module during launch. The inner hatch or ablative hatch becomes the outer hatch when the BPC is jettisoned after launch. The inner hatch closes off the Command Module and is the first to be opened by the crew in the case of the emergency.
In the case of the AS 204 testing, the outer BPC was not fully latched because of wiring that was temporarily in place for the tests. The problems maily arose with the inner hatch. As indicated by reports, one of the astronauts attempted to open the inner hatch but was unsucessful. The inner Command Module became highly pressurized as the fire heated up the module, causing the gases to expand. To release the inner hatch it was necessary to open it into the cabin, a task that would have been impossible in the higher cabin pressures. The release valve to allow pressure to be normalized, was not large enough to have any effect in the event of a fire. The crew had also been having problems evacuating in the 90 second benchmark time due to the complicated, multi-step nature of the hatch design.
NASA's Mis-management
It was determined by the review board that the organizations responsible for the planning, conduct and safety of the test had failed to identify the situation as hazardous. It was also determined that deficiencies in design, manufacture, installation, rework and quality control existed in the electrical, Environmental Control, and the communication systems. These problems werewstrongly influenced by governmental pressure to minimize cost and time and a lack of communication between NASA and it's contractors.
Plugs Out Integrated Test initiated when power applied to spacecraft. 12:55
Following completion of initial verification tests of system operation, command pilot entered spacecraft, followed by pilot and senior pilot. 18:00
Count held when command pilot noted odor in spacecraft environmental control system suit oxygen. Sample taken. 18:20
Count resumed after hatch installed. 19:42
Cabin purged with oxygen. 19:45
Open microphone first noted by test crew. 22:25
Count held while communication difficulties checked. Various final countdown functions performed during hold as communications permitted. 22:40
From this time until about 23:53 GMT, flight crew interchanged equipment related to communications systems in effort to isolate communications problem. During troubleshooting period, problems developed with ability of various ground stations to communicate with one another and with crew. 22:45
Final countdown functions up to transfer to simulated fuel cell power completed and count held at T-10 minutes pending resolution of communications problems. For next 10 minutes, no events related to fire. Major activity was routine troubleshooting of communications problem. All other systems operated normally during this period. 23:20
First indication by either cabin pressure or battery compartment sensors of a pressure increase.
23:21:11
Command pilot live microphone transmitted brushing and tapping noises, indicative of movement. Noises similar to those transmitted earlier in test by live microphone when command pilot was known to be moving. 23:30
No voice transmissions from spacecraft from this time until transmission reporting fire. 23:30:14
Slight increase in pulse and respiratory rate noted from senior pilot. 23:30:21
Data from guidance and navigation system indicated undetermined type of crew movement. Gradual rise in oxygen flow rate to crew suits began, indicating movement. Earlier in Plugs Out Integrated Test, crew reported that an unspecified movement caused increased flow rate. 23:30:24
Senior pilot’s electrocardiogram indicated muscular activity for several seconds. 23:30:30
Additional electrocardiogram indications from senior pilot. Data show increased activity but were not indicative of alarm type of response. More intense crew activity sensed by guidance and navigation system. 23:30:39
Crew movement ended. 23:30:44
All of senior pilot’s biomedical parameters reverted to “rest” level. 23:30:45
Variation in signal output from gas chromatograph. 23:30:50
Significant voltage transient recorded. 23:30:54.8
Command pilot microphone noises ended. 23:30:58.6
Oxygen flow rate reached limit of sensor. 23:30:59
Additional spacecraft movement noted 23:31:00
First voice transmission ended. 23:31:10
Fire broke from its point of origin. Evidence suggests a wall of flames extended along left wall of module, preventing command pilot, occupying left couch, from reaching valve which would vent command module to outside atmosphere. Original flames rose vertically and spread out across cabin ceiling. Scattering of firebrands of molten burning nylon contributed to spread of flames. It was estimated that opening valve
would have delayed command module rupture by less than one second. 23:31:12
First verbal indication of fire reported by crew 23:31:04.7
Cabin pressure exceeded range of transducers, 17 pounds per square inch absolute (psia) for cabin and 21 psia for battery compartment transducers. Rupture and resulting jet of hot gases caused extensive damage to exterior. 23:31:16
Beginning of final voice transmission from crew. Entire transmission garbled. Sounded like, “They’re fighting a bad fire—let’s get out. Open ‘er up.” Or, “We’ve got a bad fire—let’s get out. We’re burning up.” Or, “I’m reporting a bad fire. I’m getting out.” Transmission ended with cry of pain, perhaps from pilot. 23:31:16.8
Command module ruptured, start of second stage of fire. First stage marked by rapid temperature rise and increase in cabin pressure. Flames had moved rapidly from point of ignition, traveling along net debris traps installed to prevent items from dropping into equipment areas. At same time, Velcro strips positioned near ignition point also burned. 23:31:19.4
End of final voice transmission. 23:31:21.8
All spacecraft transmissions ended. Television monitors showed flames spreading from left to right side of command module and shortly covered entire visible area. Telemetry loss made determination of precise times of subsequent occurrences impossible. 23:31:22.4
Third stage of fire characterized by greatest conflagration due to forced convection from outrush of gases through rupture in pressure vessel. Swirling flow scattered firebrands, spreading fire. Pressure in command module dropped to atmospheric pressure five or six seconds after rupture. 23:31:25
Command module atmosphere reached lethal stage, characterized by rapid production of high concentrations of carbon monoxide. Following loss of pressure, and with fire throughout crew compartment, remaining atmosphere quickly became deficient in oxygen and could not support continued combustion. Heavy smoke formed and large amounts of soot deposited on most spacecraft interior surfaces. Although oxygen leak extinguished most of fire, failed oxygen and water/glycol lines supplied oxygen and fuel to support localized fire that melted aft bulkhead and burned adjacent portions of inner surface of command module heat shield. 23:31:30
Fire apparatus and firefighting personnel dispatched. 23:32
Attempts to remove hatches. 23:32:04
Pad leader reported that attempts had started to remove hatches. 23:32:34
Hatches opened, outer hatches removed. Resuscitation of crew impossible. 23:36
Pad leader ascertained all hatches open, left White Room, proceeded a few feet along swing arm, donned headset and reported this fact. 23:36:31
Firefighters arrived at Level A-8. Positions of crew couches and crew could be perceived through smoke but only with great difficulty. Unsuccessful attempt to remove senior pilot from command module.
23:40
Doctors arrived. 23:43
Photographs taken, and removal efforts started. 28 Jan 1967 00:30
Removal of crew completed, about seven and one-half hours after accident. 07:00
Command module 014 shipped to KSC to develop disassembly techniques for selected components prior to their removal from command module 012. 01 Feb 1967
Disassembly plan fully operational. 07 Feb 1967
Command module moved to pyrotechnics installation building at KSC, where better working conditions were available. 17 Feb 1967
Disassembly of command module completed. 27 Mar 1967
What caused the DisasterAs with most engineering disasters, the determination of the exact cause of the disaster was not easy. The Apollo 1 mission to this day still remains a mystery. The specific initiator of the fire has not yet been determined, and probably never will be. However, after investigation, a number of factors that signifacntly contributed to the disaster were determined. The fire began because of an electical short, it spread quickly because of the volatile atmospheric conditions and the presence of combustible materials inside the module. The hatch design and NASA's management of the Apollo program may have also been contributing factors.
Electrical Components
In the Apollo 204 spacecraft, many problems occurred with the electrical wiring. Teflon, has an excellent fire resistance and was therefore chosen as the covering for the wiring in the spacecraft. The specific type used for the craft was easily damaged or penetrated by abrasion. If this wiring experiences penetration by a metal structure (namely spacecraft components) a short is created at the point of conductor contact. Tests performed in highly pressurized atmosphere indicate that sparks blown from an arc can ignite combustible materials that are a short distance away from that arc. Taking this into consideration, it is quite feasible that the many arcs located by investigators on the spacecraft could have been the initiator of the fire.
Electric power distribution malfunctions in the Apollo 204 module were also related to the Environment Coolant System leakage. RS-89 was the coolant the leaked, which is a mixture of 62.5 percent ethylene glycol, 35.7 percent H20, and 1.8 percent stabilizer and corrosion inhibitor. This mixture is not highly combustable, however leakage and spillage of this fliud does present a threat. The water in this fluid evaporates much faster than the ethylene glycol. This results in a salt formation that does not evaporate and which is highly combustable. Furthermore, the residue from RS-89 is electrically conductive, therefore contact with uninsulated wire would result in current exposure to the internal atmosphere. It was proved in laboratory tests that this coolant provides an mechanism to ignite a fire.
Spacecraft Atmosphere
The high pressure and concentration levels of oxygen gas largely contributed to the dispersion of the fire. During the initail stages of the fire oxygen levels were reported to be at saturated levels which may have prompted the spread of the fire. The initial flow rate increase was probably due to crew movement which normally results in increased leakage to the cabin.
Combustible Materials
The fire moved rapidly from the point of ignition, traveling along the Raschel net debris traps which were installed in the Command Module (CM) to prevent items from dropping into equipment areas during tests. These nets were made mainly of nylon, and were thus highly combustible. Since these nets ran along large sections of the CM they generated firebrands which scattered, igniting more materials. NASA was aware of this undesirable property, but not anticipating a fire in the test runs, allowed them to be used on the ground but not during space flight.
Hatch Design
The main exit from the Command Module was through inner and outer hatches. The hatch design for the Apollo 1 spacecraft was not a cause of the disaster, but it had a large impact on the outcome. With this particular design three hatches were installed. The outermost hatch (the Boost Protective Cover (BPC)) covers the Command module during launch. The inner hatch or ablative hatch becomes the outer hatch when the BPC is jettisoned after launch. The inner hatch closes off the Command Module and is the first to be opened by the crew in the case of the emergency.
In the case of the AS 204 testing, the outer BPC was not fully latched because of wiring that was temporarily in place for the tests. The problems maily arose with the inner hatch. As indicated by reports, one of the astronauts attempted to open the inner hatch but was unsucessful. The inner Command Module became highly pressurized as the fire heated up the module, causing the gases to expand. To release the inner hatch it was necessary to open it into the cabin, a task that would have been impossible in the higher cabin pressures. The release valve to allow pressure to be normalized, was not large enough to have any effect in the event of a fire. The crew had also been having problems evacuating in the 90 second benchmark time due to the complicated, multi-step nature of the hatch design.
NASA's Mis-management
It was determined by the review board that the organizations responsible for the planning, conduct and safety of the test had failed to identify the situation as hazardous. It was also determined that deficiencies in design, manufacture, installation, rework and quality control existed in the electrical, Environmental Control, and the communication systems. These problems werewstrongly influenced by governmental pressure to minimize cost and time and a lack of communication between NASA and it's contractors.