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U.S. Astronauts in Test Flight of Apollo 1 Got Burned to Death
A test spaceflight on launch pad razed by fire was renamed Apollo 1
President John F. Kennedy, on May 25,1961, issued a challenge to land men on the moon “before this decade is out.” He made that call for the United States before Congress. The feat should be for men to land on the moon and return safely to earth. In a way, it was a response to the technological advance displayed by the Russians who had launched Sputnik I into orbit earlier.
Landing on the moon had been accomplished on July 24,1969 by Apollo 11.
The mission to land men, or rather Americans, on the moon started with Apollo 1. Why did it take Apollo I to Apollo 10 before Apollo 11 could land on the moon?
The excitement over the landing of men on the moon is still very much alive. Amidst the celebrations it is now time to understand how the landing came about.
Well, people who were in charge of developing the aims, strategies, spacecraft, astronauts, physical theories, communications systems, computer programs, scientific experiments and allocating funds have long understood.
What could a common mortal like me relish out of (or mourn over) the Apollo program?
The Apollo program was baptized by fire!
That is not a metaphor. Apollo 1 was razed by fire killing three astronauts.
How did that happen? It happened in a simulation spaceflight.
There are several things to test in a simulation spaceflight. One is power supply.
How does the spacecraft perform with its own power supply?
Three astronauts are out to record that performance in a launch simulation; not yet a true launch. The command module is disconnected from the electrical power supply. Astronauts enter the module which is sealed, then pressurized. The command and service module (CSM) life-support system is maintained at cabin pressure at 5 pounds per square inch, which is only one-third of the pressure at sea level (14.7 pounds per square inch). Pure oxygen is used in the CSM. The command module is built for a vacuum in space, that is, with a greater pressure inside than outside. This is to guard against the outside pressure to cause outside air to leak into the command module.
For the simulation flight, the module is filled with pure oxygen with a higher pressure inside at 15.5 pounds per square inch.
Given that pure oxygen is a fire hazard. It appears that the designers and staff at NASA (National Aeronautics and Space Administration) do not consider it likely that fire would occur in the cabin. The hypothesis (scientific guess) is that cabin fire would not sustain itself in space. If a fire starts, weightlessness in space would prevent air current to carry oxygen to the fire. However, this hypothesis cannot be proven true or false if the module is on earth and not in space. A launch simulation would test this hypothesis, among others, on the command module of AS-204. (A means Apollo; S means Saturn, the launch rocket. The first Apollo-Saturn launch was “mission AS-201”).
Three astronauts, Virgil “Gus” Grissom, Roger B. Chaffe, and Edward H. White, were scheduled to fly 14 days in a first manned mission (AS-204), part of a series of spaceflights toward a landing on the moon.
On January 27,1967 they boarded AS-204 to make a test on the launch pad at the Kennedy Space Center, Florida; not yet on a real spaceflight.
Five hours into the simulation flight, an electrical spark occurred and ignited a fire in the cabin. The fire, fed by 100 percent pure oxygen, abruptly increased temperature and pressure inside the cabin. “Choking black smoke” was produced in profusion.
Edward H. White began executing evacuation steps. In practice, the six bolts of the hatch took 90 seconds to undo. However, even if White had removed the bolts in less than 90 seconds the astronauts could not open the hatch because it was designed to swing inward. Pressure from inside the command module kept the hatch tightly closed. If the inside pressure is greater than the outside pressure by 0.25 pounds per square inch it is impossible to open the hatch. Even if there were no fire, the pressure inside the cabin is greater than that at the outside.
The pressure within the cabin rose to 30 pounds per square inch due to the fire in confined space. In five seconds more, making the total duration of fire within 25 seconds, the 100 percent pure oxygen was exhausted and the fire stopped.
“All three astronauts died before they could be rescued” (Magill, F.N., editor. “Apollo 1-6.” Magill’s Survey of Science.1989.1:41).
The hypothesis that the fire would smother itself was proven true. Unfortunately, at the cost of the lives of Grissom, Chaffe and White.
Investigation of the fire showed tangled wires and access panels slammed shut. The astronaut’s spacesuits made of Nomex cloth, and other combustible materials accelerated spread of fire. The coolant fluid which consisted mostly of water and ethylene glycol, a chemical, turned an electric conductor and flammable when the water had evaporated. This coolant leaked during the early stage of fire due to poor soldering. The spark was believed to have been triggered by an electrical arc located near the lithium hydroxide, a chemical for use to remove carbon dioxide exhaled by astronauts.
Owing to the fire, the command module underwent 1,500 modifications. The hatch was redesigned such that it swings outward and could be opened in 12 seconds. The material for spacesuits was changed to Beta cloth that would not burn at 500 degrees Celsius and would melt not burn only at 800 degrees Celsius. Pure oxygen at 5 pounds per square inch was used in the operation of the command module.
“The tragedy-ridden AS-204 mission was dubbed Apollo 1” in honor of Grissom, Chaffe and White. Each of them was awarded the "Congressional Space Medal of Honor"posthumously.