Finding out what happened
The Apollo 1 fire that killed Gus Grissom, Ed White and Roger Chaffee on 27 January 1967 was investigated by a panel NASA set up within days: the Apollo 204 Review Board. The number comes from the Saturn launch vehicle designation, AS-204, used for the mission before it was renamed Apollo 1. The board was chaired by Floyd Thompson, director of NASA’s Langley Research Center, and its members came from NASA, the Air Force, the Bureau of Mines and other bodies. Astronaut Frank Borman was among them, which gave the inquiry an informed view of how astronauts actually worked in the spacecraft.
The board examined the burned command module in detail. Investigators photographed and documented the cabin, removed parts in a controlled sequence and cross-checked each step against records of the spacecraft’s assembly. The board submitted its report to NASA in April 1967, and the findings were presented publicly and to Congress, which held its own hearings.
The pure oxygen cabin
The most important single factor was the atmosphere. During the test the cabin was filled with pure oxygen at a pressure of about 16.7 pounds per square inch, roughly 2 psi above normal sea-level air pressure of 14.7 psi. In space the spacecraft would have operated on oxygen at much lower pressure, but on the ground the cabin had to be held above outside pressure, which meant more oxygen in the air the crew breathed.
The design had a reasoned history. A single-gas oxygen system was lighter and simpler than a mixed-gas one, and it had been used in the earlier Mercury and Gemini spacecraft without a fire in flight. But materials that are merely hard to ignite in ordinary air can burn fiercely in oxygen-rich air. At the elevated pressure in the test, the fire spread extremely quickly. The board concluded that the atmosphere was a central reason a small ignition became unsurvivable within seconds.
Flammable materials
The command module contained a great deal of material that burned readily in that atmosphere. The board’s findings drew attention to nylon netting, Velcro fastening strips, foam, cloth and other items distributed around the cabin, including the crew’s own equipment. Plastics and wiring insulation also contributed. Once the fire started, these materials gave it fuel throughout the cabin.
The investigators also found that the amount of such material had grown as the spacecraft was fitted out, and that nobody had treated the total quantity as a serious hazard in a pure oxygen cabin. That finding reflected a general problem that the report did not try to hide: the fire risk had not been taken seriously enough during design and testing.
The ignition source
The board could not identify the exact point of ignition with certainty. It concluded that the most likely cause was an electrical arc, probably from damaged wiring in the lower part of the cabin on the left side, near the equipment bay. It noted problems with the way wiring and plumbing were installed and protected, including the presence of coolant lines carrying a flammable fluid. Because the fire destroyed the evidence, the report did not name a single failed component as proven. It said the conditions for a fire were present, and that a spark in the wrong place was enough.
The hatch
The most painful finding concerned escape. The crew’s hatch was an inward-opening plug type, made of an inner and outer section, and it had to be removed manually. Even in a rehearsal, a trained crew needed roughly a minute or more to open it. During the fire, the rising cabin pressure pressed the inner hatch even tighter against its seal, so that it could not be opened against the pressure at all.
The board concluded that the crew did not have the time to get out in any case, since the fire proceeded so quickly that they lost consciousness within a very short time, probably well under a minute. But it also said the hatch design was unacceptable, because it could not be opened quickly from the inside or from the outside under emergency conditions. Ground crews also faced heat, smoke and the lack of firefighting and rescue equipment suited to such an event.
What the board concluded
In summary, the report found that:
- The test was conducted in a hazardous condition that had not been recognised as such, so emergency equipment and procedures were inadequate.
- The cabin held pure oxygen at above-normal pressure.
- Combustible materials were widespread inside the spacecraft.
- Wiring and plumbing showed poor installation and protection.
- The hatch design prevented rapid escape or rescue.
- Communications between crew and the control room were poor during the test.
The board also criticised weaknesses in management and quality control between NASA and the contractor, North American Aviation. These points were widely discussed in the press and in congressional hearings, and they led to personnel changes and a long programme of corrective work.
Why the report mattered
The report was unusually frank for an official document of the period, written while the space race with the Soviet Union put NASA under intense pressure to keep to its schedule. It did not blame the crew, and it pinned most of the responsibility on a chain of overlooked risks. The recommendations for changes to the spacecraft, its materials and its test procedures set the course for the Apollo spacecraft redesign that followed, and the stricter approach to safety shaped later NASA practice well beyond Apollo.