January 19, 2016
Fire is one of the most destructive forces in the world. But it can also be a great impetus for change. The great Chicago Fire brought about many changes in building codes in the years following the blaze. Another famous fire that occurred on January 27, 1967, also brought about many innovations and modifications that most assuredly have saved lives.
The notoriety of this fire was not due to the number of lives that were lost. In fact, there were only three casualties total. It is famous because of who the casualties were and that no one of their kind had ever been killed before in the line of duty. The three men who died were astronauts.
Virgil Grissom, Edward White, and Roger Chaffee were the crew of Apollo I and were killed when a fire sparked inside the space capsule during a routine ground test. While the exact cause of the fire is not known, conditions inside the capsule were ripe for fire and certainly led to the astronaut’s demise.
The Apollo Program was NASA’s attempt to put man on the moon and after the fire scientists had to reevaluate several design features of the spacecraft. Like every NASA vehicle before it, the inside environment of Apollo I had been pure oxygen. This was a design feature that was intended to lower the weight of the vehicle. Unfortunately, it also made fire very easy to start.
Afterwards, NASA scientists redesigned Apollo to increase the safety of everyone on board. Oxygen levels were reduced to 34% in all pressurized modules. The walls of the vehicles were also thickened to be able to handle the additional pressure. But at these lower levels, the probability of an electrical spark igniting a fire were tremendously lowered.
Another facet of Apollo that certainly led to the spread of the fire was the amount of flammable material inside the spacecraft. Velcro was widely used by NASA up to that point and after the tragedy the amount of Velcro was drastically reduced. NASA tested all materials inside the cabin for flammability which led to the creation of new fire safety measures.
All redesigns were performed with the thought of fire safety during spaceflight in mind. The insulation surrounding electrical wires was redesigned after Apollo I. The special coating is now so fire resistant, it cannot burn even in a pure oxygen environment.
But perhaps the greatest change brought about by the fire was the redesign of the capsule hatch. After the fire erupted inside Apollo, the astronauts tried to escape through the hatch but could not get it open. The procedures to open the hatch were too complex and took far too long to save the astronauts lives. However, it was a design flaw that most likely led to their demise.
The door to the hatch on Apollo I opened inward on the capsule. Under any increased air pressure higher than regular atmospheric levels, the door would be impossible to open. The fire inside definitely raised the cabin pressure and sealed the astronauts inside.
In the aftermath, the doors were redesigned to open outward to increase safety. A similar change in common design elements was made with fire exit doors in theaters after the Iroquois Theater Fire of 1903 in Chicago.
Explosive bolts were added also added to the spacecraft so that the astronauts could quickly escape the capsule in the event of an emergency. These elements have been present on NASA spacecraft since Apollo I and will even be implemented on the new Orion Spacecraft which will eventually take humans into deep space.
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