Apollo 1 was a command module developed in the U.S. Apollo manned lunar landing program. It was scheduled for the first manned mission on February 21, 1967 (1, 2). To make sure that the spacecraft would operate normally when it was detached from external power, a “plugs-out” test was carried out at Cape Canaveral on January 27, 1967 (1, 2). A fire occurred inside of the command module during the test and rapidly destroyed the command module (1). All three crew members, Command Pilot Virgil Grissom, Senior Pilot Edward H. White and Pilot Roger B. Chaffee, died in the accident (1, 2).
Apollo 1 was shipped to NASA Kennedy Space Center on February 1, 1967 (2), and NASA started investigating the causes of the fire on February 3, 1967 (1). Several conditions that could have led to the fire had been identified by the Investigation Board.
- An electricity wire stripped with its Teflon insulation was found to run near a cooling line carrying ethylene glycol, a combustible coolant (1, 2, 3). The electrolysis of ethylene glycol could have been the ignition source of the fire (1, 3).
- A design flow was found in Apollo 1, that is, the interior of the command module was made from many combustible materials (1, 2, 3).
- The cabin of Apollo 1 used a high-pressure (16.7 psi) pure oxygen atmosphere, in order to alleviate decompression sickness and to prevent air leaking from the cabin to astronaut’s spacesuit (1, 2, 3).
- The command module was designed with an inward-opening hatch. Due to the increase in pressure caused by the fire, the astronauts were unable to open the hatch during the accident (1, 2, 3).
- The test planners were not prepared for the accident, and the emergency equipment was inadequate (1, 2, 3).
After the fire, the United State Congress conducted investigations, and NASA and North American Aviation were both blamed for the design flaws and the careless assembling in Apollo project (1). The Apollo command module was redesigned. The atmosphere applied to the cabin was changed to a nitrogen/oxygen (40%/60%, v/v) mixture with a lower pressure (14.7 psi) (1). Non-flammable, fire-resistant materials were used for astronaut suits and for building the interior of the cabin (1). In addition, wiring and plumbing were protected with better insulation, and a large quantity of wring problems were identified and corrected (1).
Reference
- Apollo 1. Wikipedia, the Free Encyclopedia, 9 Apr. 2013. Web. 17 Apr. 2013.
- Apollo 1: The Fire 27 January 1967. NASA Special Publication. Web. 17 Apr. 2013.
- Apollo 204 Review Board Final Report. NASA, 5 Apr. 1967. Web. 17 Apr. 2013.
