A test that was not supposed to be dangerous
On the evening of 27 January 1967, astronauts Virgil “Gus” Grissom, Edward White and Roger Chaffee were sealed inside their Apollo command module on top of a Saturn IB rocket at Launch Complex 34, Cape Kennedy, Florida. They were taking part in what NASA called a “plugs-out” test: a rehearsal of the countdown in which the spacecraft runs on its own internal power. The rocket was not fuelled, and the test was officially classed as non-hazardous. That classification later became one of the most criticised details of the whole episode.
The mission, designated AS-204 and later renamed Apollo 1, was planned as the first crewed flight of the Apollo programme, an Earth-orbit mission scheduled for February 1967. Grissom, then 40, was one of the original Mercury astronauts and had flown on Gemini 3. White, 36, had made the first American spacewalk during Gemini 4 in 1965. Chaffee, 31, was a rookie preparing for his first spaceflight.
The fire
The test ran into problems from the start, including a sour smell in the spacecraft’s oxygen supply and persistent difficulty with the communications loop between the crew and the control teams. The countdown was held several times. In the early evening, at about 6:31 p.m. Eastern time, a voice from the spacecraft reported a fire. The transmission was brief and ended abruptly.
The cabin was filled with nearly pure oxygen at a pressure slightly above that of the outside air. In that atmosphere, many materials that normally burn slowly ignite readily and burn fast, and the pressure rose rapidly as the fire spread. The crew could not escape. The hatch was a multi-part design that opened inward and had to be unlatched against the pressure building inside the cabin, which made it impossible to open in the seconds available. Ground crew who rushed to help were driven back by heat and smoke, and it took several minutes to get the hatch open. All three men had died. The investigation concluded that they were killed by the effects of the fire, chiefly smoke inhalation and the loss of breathable atmosphere, rather than by the flames alone, and that they lost consciousness very quickly.
What the investigators found
NASA set up a review board under Floyd Thompson, the director of the agency’s Langley Research Center. Its report, delivered in April 1967, reached several main conclusions:
- The most probable ignition source was an electrical arc somewhere in the cabin wiring, although a single definite point of ignition was not conclusively identified.
- The cabin contained a large amount of flammable material, including nylon netting and Velcro, and the pure-oxygen atmosphere allowed the fire to spread with extreme speed.
- The hatch design prevented a quick escape or rescue.
- Wiring, plumbing and quality control in the command module were criticised, as were emergency procedures and the lack of readiness for a fire on the pad.
The report did not simply blame one component. It described a combination of hazards that had been accepted piecemeal, and it questioned the assumption that a ground test without fuel was safe. The contractor, North American Aviation, and NASA management both faced sharp scrutiny. Congressional hearings followed, and the programme’s leadership changed in the following months.
The redesign
The changes made to the spacecraft before any crew flew again were extensive. The main ones were:
- A new hatch. A single-piece hatch that opened outward could be released quickly by the crew, and was designed to open in a matter of seconds.
- A different atmosphere on the ground. During launch preparations, the cabin would use a mixture of oxygen and nitrogen rather than pure oxygen. Pure oxygen at low pressure was still used once in space, which saved weight and complexity.
- Less flammable material. Flammable fabrics and plastics were replaced or covered, and wiring was rerouted and protected.
- Tighter quality control and testing. Wiring and plumbing were reworked, and the spacecraft’s documentation and inspection procedures were made stricter.
The earlier version of the spacecraft was set aside and a heavily revised Block II design became the basis for the flights that followed. NASA also renamed the mission Apollo 1 in April 1967, at the request of the astronauts’ families, and used that name for the flight that never took place.
How the programme recovered
Crewed Apollo flights were paused for almost two years. In that time, uncrewed tests continued. In November 1967, Apollo 4 carried out the first launch of the huge Saturn V rocket, a test the programme needed to stay on course even as the investigation continued. The first crewed Apollo mission, Apollo 7, flew in October 1968 with Wally Schirra, Donn Eisele and Walt Cunningham, and tested the redesigned command module in Earth orbit. Later missions carried on to lunar orbit, and Apollo 11 landed on the Moon in July 1969, within the decade set as a goal by President Kennedy in 1961.
It is difficult to say with certainty how much time the fire cost the programme, since the Apollo hardware and the Saturn V needed further development in any case. What the records do show is that the disaster forced a sober reassessment of risk. It remains cited in discussions of safety culture, partly because the warning signs were present in the cabin’s design before the accident.
The wider context of 1967
The fire happened at a tense moment in the space race. Americans and Soviets were both preparing complex new spacecraft, and both would suffer a fatal accident that year. In April 1967, the Soviet cosmonaut Vladimir Komarov died when Soyuz 1 crashed on its return to Earth, and the loss of two national programmes’ crews in a single season shaped the sober mood. In the same year, the Outer Space Treaty was signed, setting out principles for how nations should behave beyond Earth, and the work of Lunar Orbiter and Surveyor 3 continued to prepare the ground for a landing.
Remembered
Grissom, White and Chaffee are commemorated at the Kennedy Space Center and elsewhere. The launch pad’s concrete structure now carries memorial plaques, and the three men are buried at Arlington National Cemetery (Grissom and Chaffee) and West Point (White). Their loss is remembered in NASA’s annual day of remembrance in late January, which also marks other lives lost in the space programme.