Apollo 1

The launch simulation on January 27, 1967, on pad 34, was a "plugs-out" test to determine whether the spacecraft would operate nominally on (simulated) internal power while detached from all cables and umbilicals. Passing this test was essential to making the February 21 launch date. The test was considered non-hazardous because neither the launch vehicle nor the spacecraft was loaded with fuel or cryogenics and all pyrotechnic systems (explosive bolts) were disabled.[11]
At 1:00 pm EST (1800 GMT) on January 27, first Grissom, then Chaffee, and White entered the command module fully pressure-suited, and were strapped into their seats and hooked up to the spacecraft's oxygen and communication systems. Grissom immediately noticed a strange odor in the air circulating through his suit which he compared to "sour buttermilk", and the simulated countdown was put on hold at 1:20 pm, while air samples were taken. No cause of the odor could be found, and the countdown was resumed at 2:42 pm. The accident investigation found this odor not to be related to the fire.[11]
Three minutes after the count was resumed the hatch installation was started. The hatch consisted of three parts: a removable inner hatch which stayed inside the cabin; a hinged outer hatch which was part of the spacecraft's heat shield; and an outer hatch cover which was part of the boost protective cover enveloping the entire command module to protect it from aerodynamic heating during launch and from launch escape rocket exhaust in the event of a launch abort. The boost hatch cover was partially, but not fully, latched in place because the flexible boost protective cover was slightly distorted by some cabling run under it to provide the simulated internal power (the spacecraft's fuel cell reactants were not loaded for this test). After the hatches were sealed, the air in the cabin was replaced with pure oxygen at 16.7 psi (115 kPa), 2 psi (14 kPa) higher than atmospheric pressure.[11][17]: Enclosure V-21, [181] 
Movement by the astronauts was detected by the spacecraft's inertial measurement unit and the astronauts' biomedical sensors, and also indicated by increases in oxygen spacesuit flow, and sounds from Grissom's stuck-open microphone. The stuck microphone was part of a problem with the communications loop connecting the crew, the Operations and Checkout Building, and the Complex 34 blockhouse control room. The poor communications led Grissom to remark: "How are we going to get to the Moon if we can't talk between two or three buildings?"
The simulated countdown was put on hold again at 5:40 pm while attempts were made to troubleshoot the communications problem. All countdown functions up to the simulated internal power transfer had been successfully completed by 6:20 pm, and at 6:30 the count remained on hold at T minus 10 minutes.[11]


The crew members were using the time to run through their checklist again, when a momentary increase in AC Bus 2 voltage occurred. Nine seconds later (at 6:31:04.7), one of the astronauts (some listeners and laboratory analysis indicate Grissom) exclaimed "Hey!", "Fire!",[17]: 5–8  or "Flame!";[23] this was followed by two seconds of scuffling sounds through Grissom's open microphone. This was immediately followed at 6:31:06.2 (23:31:06.2 GMT) by someone (believed by most listeners, and supported by laboratory analysis, to be Chaffee) saying, "[I've, or We've] got a fire in the cockpit." After 6.8 seconds of silence, a second, badly garbled transmission was heard by various listeners as:
•	"They're fighting a bad fire—Let's get out ... Open 'er up",
•	"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 ..."
The transmission lasted 5.0 seconds and ended with a cry of pain.[17]: 5–8, 5–9 
Some blockhouse witnesses said that they saw White on the television monitors, reaching for the inner hatch release handle[11] as flames in the cabin spread from left to right.[17]: 5–3 
The heat of the fire fed by pure oxygen caused the pressure to rise to 29 psi (200 kPa), which ruptured the command module's inner wall at 6:31:19 (23:31:19 GMT, initial phase of the fire). Flames and gases then rushed outside the command module through open access panels to two levels of the pad service structure. The intense heat, dense smoke, and ineffective gas masks designed for toxic fumes rather than smoke, hampered the ground crew's attempts to rescue the men. There were fears the command module had exploded, or soon would, and that the fire might ignite the solid fuel rocket in the launch escape tower above the command module, which would have likely killed nearby ground personnel, and possibly have destroyed the pad.[11]
As the pressure was released by the cabin rupture, the rush of gases within the module caused flames to spread across the cabin, beginning the second phase. The third phase began when most of the oxygen was consumed and was replaced with atmospheric air, essentially quenching the fire, but causing high concentrations of carbon monoxide and heavy smoke to fill the cabin, and large amounts of soot to be deposited on surfaces as they cooled.[11][17]: 5–3, 5–4 
It took five minutes for the pad workers to open all three hatch layers, and they could not drop the inner hatch to the cabin floor as intended, so they pushed it out of the way to one side. Although the cabin lights remained on, they were unable to see the astronauts through the dense smoke. As the smoke cleared they found the bodies, but were not able to remove them. The fire had partly melted Grissom's and White's nylon space suits and the hoses connecting them to the life support system. Grissom had removed his restraints and was lying on the floor of the spacecraft. White's restraints were burned through, and he was found lying sideways just below the hatch. It was determined that he had tried to open the hatch per the emergency procedure, but was not able to do so against the internal pressure. Chaffee was found strapped into his right-hand seat, as procedure called for him to maintain communication until White opened the hatch. Because of the large strands of melted nylon fusing the astronauts to the cabin interior, removing the bodies took nearly 90 minutes.[11]
Deke Slayton was possibly the first NASA official to examine the spacecraft's interior.[24] His testimony contradicted the official report concerning the position of Grissom's body. Slayton said of Grissom and White's bodies, "it is very difficult for me to determine the exact relationships of these two bodies. They were sort of jumbled together, and I couldn't really tell which head even belonged to which body at that point. I guess the only thing that was real obvious is that both bodies were at the lower edge of the hatch. They were not in the seats. They were almost completely clear of the seat areas.




As a result of the in-flight failure of the Gemini 8 mission on March 17, 1966, NASA Deputy Administrator Robert Seamans wrote and implemented Management Instruction 8621.1 on April 14, 1966, defining Mission Failure Investigation Policy And Procedures. This modified NASA's existing accident procedures, based on military aircraft accident investigation, by giving the Deputy Administrator the option of performing independent investigations of major failures, beyond those for which the various Program Office officials were normally responsible. It declared, "It is NASA policy to investigate and document the causes of all major mission failures which occur in the conduct of its space and aeronautical activities and to take appropriate corrective actions as a result of the findings and recommendations."[26]
Immediately after the fire NASA Administrator James E. Webb asked President Lyndon B. Johnson to allow NASA to handle the investigation according to its established procedure, promising to be truthful in assessing blame, and to keep the appropriate leaders of Congress informed.[27] Seamans then directed establishment of the Apollo 204 Review Board chaired by Langley Research Center director Floyd L. Thompson, which included astronaut Frank Borman, spacecraft designer Maxime Faget, and six others. On February 1, Cornell University professor Frank A. Long left the board,[28] and was replaced by Robert W. Van Dolah of the U.S. Bureau of Mines.[29] The next day North American's chief engineer for Apollo, George Jeffs, also left.[30]
Seamans ordered all Apollo 1 hardware and software impounded, to be released only under control of the board. After thorough stereo photographic documentation of the CM-012 interior, the board ordered its disassembly using procedures tested by disassembling the identical CM-014 and conducted a thorough investigation of every part. The board also reviewed the astronauts' autopsy results and interviewed witnesses. Seamans sent Webb weekly status reports of the investigation's progress, and the board issued its final report on April 5, 1967


According to the Board, Grissom suffered severe third-degree burns on over one-third of his body and his spacesuit was mostly destroyed. White suffered third-degree burns on almost half of his body and a quarter of his spacesuit had melted away. Chaffee suffered third-degree burns over almost a quarter of his body and a small portion of his spacesuit was damaged. The autopsy report determined that the primary cause of death for all three astronauts was cardiac arrest caused by high concentrations of carbon monoxide. Burns suffered by the crew were not believed to be major factors, and it was concluded that most of them had occurred postmortem. Asphyxiation occurred after the fire melted the astronauts' suits and oxygen tubes, exposing them to the lethal atmosphere of the cabin.

Major causes of accident[edit]
The review board identified several major factors which combined to cause the fire and the astronauts' deaths:[11]
•	An ignition source most probably related to "vulnerable wiring carrying spacecraft power" and "vulnerable plumbing carrying a combustible and corrosive coolant"
•	A pure oxygen atmosphere at higher than atmospheric pressure
•	A cabin sealed with a hatch cover which could not be quickly removed at high pressure
•	An extensive distribution of combustible materials in the cabin
•	Inadequate emergency preparedness (rescue or medical assistance, and crew escape)