Day 20: The Apollo 1 Tragedy Changed NASA and Spaceflight Forever
July 21, 1961. Astronaut Virgil āGusā Grissom has splashed down on his Mercury Spacecraft Liberty Bell 7, and now sits in his capsule-turned-boat. As Gus sits and performs post-flight assignments, something goes wrong: the pyrotechnic bolts on the spacecraft hatch meant to be detonated manually were prematurely triggered. The hatch flew off, leaving the capsule with a wide open holeā a fact which meant the spacecraft would flood in the turbulent waves of the Atlantic Ocean before the circling helicopters could recover it in time.
Luckily, Gus was able to get out of the capsule quickly before it filled with water; however, the line connecting the capsule to the helicopters failed and the capsule sunk to the bottom of the ocean (it was recovered 38 years later in 1999 at depths greater than that of the Titanic).
The hatch malfunction was at first blamed on Gus ā but testing later showed that the design of the hatch was at fault for the premature ejection. Despite his exoneration from this fault, this very issue would come back to haunt NASA and Grissom himself in 1967.
5 more missions utilizing the one-man Mercury capsule followed Grissomās, and 10 more would be flown using the Gemini (2-manned: Gemini twins) capsule; all were successful.
The Gemini Missions did not have hatches, opting instead for double door systems. When it came time to design the Apollo Capsule, though, NASA engineers were once again faced with the hatch issue: they had to ensure that the hatch would not blow in over pressurization or decompression events. The hatch was therefore designed in such a manner that it would open inward and only once atmospheric pressures inside were equalized to outside. Fate would prove this a fatal engineering flaw, hindering rescue operations and essentially making it impossible to open the hatch in case of an emergency until the capsule was decompressed.
Another fatal flaw in the new Apollo Capsule lay in its atmosphere. Nitrogen has a tendency to form bubbles in blood when subject to rapid pressure changes, as would be experienced in a spacecraft. To divers, this condition is known as decompression sickness, or āthe bendsā, and it has fatal consequences. In order to ensure that no Nitrogen enter the bloodstream of Astronauts, Astronauts would breathe pure oxygen, and engineers developed a one-gas system for pressurizing their capsules: pure Oxygen, an extremely flammable substance, would pressurize the entire capsule.
The X-15 (the supersonic aircraft test program that Neil Armstrong was a part of), for example, had a two-gas system for cockpit pressurization. Pilots would breathe pure O2, but the atmosphere they sat in was pure Nitrogen, which acts as a better fire suppressant than water (fire needs O2, so Nitrogen starves fire). By using the Nitrogen atmosphere, fire was essentially an impossibility in the X-15s cockpit. Now then, one may ask, why wouldnāt NASA implement this far safer system into spacecraft capsules as well? It is a simple answer: two-gas systems are much more complicated and expensive, and since NASA had flown 16 previous missions with the one-gas system, they were confident.
This confidence proved fatal. The Block 1 Apollo Capsules were enshrined in engineering shortcuts, hardware issues, and software malfunctions. The biggest of its flaws was the aforementioned one-gas system, and that would be made clear on January 27, 1967.
It was to be the first manned Apollo flight. Astronauts Gus Grissom, Ed White (the first man to perform an EVA), and Roger Chaffee (a rookie astronaut) were placed in the Capsule that fateful morning for a routine systems test prior to their orbital flight a month later. All 3 astronauts had been a part of the manufacturing process of the capsule, they all knew it better then they knew their own homes. They trusted it. The 3 astronauts sat in the pure O2 environment for 3 hours performing tests and having a hard time communicating with CAPCOM.
Suddenly, by the left foot of the Commander, a spark flew. Their fate was sealed.
Grissom: āWe got a fire in the cockpit!ā
In 3 seconds, fire engulfed the pure-oxygen environment, turning the inside of the capsule into a 2500*F oven. The 3 astronauts had seconds to process the situation before going into cardiac arrest from Carbon Monoxide poisoning (thankfully before the fire got to them). The fire burned for 3 minutes, until purge systems flooded the capsule with regular atmosphere and it was extinguished. Launch Pad personnel were unable to open the hatch until the pressure was relieved. When they did, they were met with a gruesome scene. None of the astronauts survived. In 6 years NASA had made 16 flights without a single astronaut injury ā and now 3 heroes were lost in mere seconds.
America mourned the loss of the 3 astronauts. There were threats of canceling the Apollo program reaching as far as Congress. It was obvious that changes had to be made, or the program ā and the prospect of landing men on the moon by the end of the decade ā would not be seen through.
A new spacecraft, labeled the Block 2 CSM, was put into production. The hatch now opened outwardly and quickly, allowing the rescue of the astronauts quickly if need be. The classic Apollo Launch Suit was adopted, with materials that would not burn even at temperatures as great as 2500*F. NASA finally got around to developing a two-gas system, where Nitrogen atmosphere would be used on the ground and pure O2 atmosphere would be used in Orbit, where the risk of fire is minimal due to the low-pressure environment of zero-g.
NASA has seemingly only recently learned to preemptively prepare for disasters. Their habit of failing to address issues until they cause problems was the key factor behind Apollo 1 and just as well in the Challenger and Columbia disasters later on: for years Engineers, Flight Surgeons and even Gus Grissom himself had been voicing concerns about safety issues including the one-gas system. I hope modern-day NASA takes into account the lessons written in blood with the Artemis Program, and I truly hope history will not have to repeat itself.
