The Apollo I Disaster: What Went Wrong

 

On July 21st, 1961, the second U.S. manned suborbital spaceflight, Mercury-Redstone 4, also known as Liberty Bell 7, launched with Gus Grissom at the controls. The mission was to continue to research and study man’s capabilities in space, as well as test new features in the spacecraft, one of which was an explosively actuated side hatch. This hatch was designed to utilize an explosive charge that would fracture the 70 bolts that attached the hatch, and quickly separate it from the spacecraft. Both the astronaut inside and the support team outside had the ability to trigger this function, which was meant as a safety device in case the astronaut needed to quickly exit the spacecraft. 

Gus Grissom

Shortly before the launch, a technician noticed that 1 of the 70 bolts was misaligned, but it was determined that the other 69 would suffice and nothing was done about it. The spaceflight went as planned and reached an altitude of 102.8 nautical miles, with a period of weightlessness lasting about 5 minutes. The re-entry process seemed to be a success too as the parachutes opened and Grissom successfully splashed down at Cape Canaveral. Then, as Grissom awaited the helicopters the pick him up, the explosive hatch prematurely activated. This caused water to fill the spacecraft and put Grissom’s life in danger. Grissom was able to get out, but was now swimming around, awaiting rescue. He almost drowned as helicopters were at first more focused on saving the spacecraft. It was too heavy to save, but Grissom was rescued just in time. Liberty Bell 7 sunk to the bottom of the ocean and was not recovered until 1999, 38 years later.

Gus Grissom being rescued from Liberty Bell 7 accident

Five and half years after the launch of Liberty Bell 7, as the Apollo program began its mission to get a United States astronaut to the moon before the end of the decade, Gus Grissom would find himself in another horrifying situation involving a hatch. Only this time, instead of opening too soon, it couldn’t be opened at all.

Apollo 1 – originally known as AS-204 - was intended to be the first crewed mission of the Apollo program and consisted of Grissom, the command pilot, along with Ed White, and Roger Chaffee. The aerospace manufacturing company who built the CSM – Command Service Module – were called North American Aviation. They wanted the hatch to have the same type of explosive safety device as Liberty Bell 7 had, despite the premature explosion. NASA disagreed and did not want to risk a similar accident. Instead, they created a hatch that could, under certain circumstances, be next to impossible to open. It consisted of three doors – an inner main hatch, a middle heat shield hatch and an outer hatch. The cumbersome inner hatch opened inward and was held shut by latches operated by ratchets. It took special tools, a lot of effort, strength and time - at least minute and a half - to open the hatch - under ideal conditions. Ed White used to practice opening the hatch as a workout. To make matters worse, if the pressure inside the cabin was any higher than the pressure exerted by the weight of the natural atmosphere, the hatch would become impenetrably sealed. No one man or even three men could have a prayer opening it. Unfortunately, the atmosphere inside the command module was higher than natural, due to NASA’s second fateful decision.

This decision was to use a pure oxygen environment for the astronauts, as opposed to the nitrogen/oxygen mixture used in some previous space programs. NASA decided to go with a more pure, breathable environment that they determined would be safer and less complicated. Pure oxygen eliminated the weight and complexity that would have been needed for a mixture with nitrogen. As for a potential fire hazard, they reasoned that there were no flammable hazards or sources that could cause a spark in the control module – and if there were no sparks, there could be no fire. One would have just take their word for it when examining the Apollo 1 control module, which had bundles of unprotected wire on the floor which were being constantly cut, spliced and re-routed. If there was an environment that existed in the world where no one had to worry about a spark, this didn’t look the one. Nevertheless, NASA didn’t even simulate what would happen if there was a spark inside the CSM before allowing the astronauts to enter and perform the “plugs out” test – a routine test that checks the spacecraft systems.

The crew of Apollo 1

During this “plugs out” test, several issues occurred, which is nothing new to NASA – but so far, despite several close calls, major tragedies had been avoided. Besides Liberty Bell 7, there was Gemini 8, which spiraled out of control, nearly killing astronauts Neil Armstrong and David Scott. On this day in January of 1967, however, the communications issues seemed minor, although they frustrated Grissom, who asked, “How are we going to get to the moon if we can’t talk between two or three buildings?” Shortly thereafter, Director of Flight Crew Operations Deke Slatyon, who considered joining the astronauts in the control module before ultimately deciding against it, thought he heard Grissom’s voice saying one word – “Fire.”

Roger Chaffee exclaimed “We’ve got a fire in the cockpit.” Less than 30 seconds after the initial report of fire, the last transmission came through – a horrifying sound of pain. The pure oxygen helped the fire to grow out of control in a matter of seconds and the astronauts never stood a chance. The intense heat and smoke prevented rescuers from getting to the astronauts in a timely manner. “It’s too hot!,” they could be heard saying as they attempted to get to and open the hatch. When they could finally get to it, it took several minutes to get it open. The next communication came from the pad leader, observing what was inside. He said, “I better not describe what I see.”

The death of the three astronauts that day shocked the nation and the NASA community as well, who were in general prepared for such a tragedy and understood the risks. However, it was expected for such a tragedy to occur during an official space mission – not during a routine test with technicians on every corner and a shuttle that wasn’t even fueled.

So, what went wrong? As you may have already surmised after the descriptions of the hatch and the pure oxygen, this was a disaster waiting to happen. Not surprisingly, NASA was wrong about a spark not being possible. A review board determined that in the lower equipment bay, there were some damaged wires and flammable fumes leaking from a coolant pipe, which caused a spark. Flammable netting and foam pads helped strengthen the blaze. Even with a normal one piece hatch that wasn’t impossible to open when pressurized, the crew would have struggled to escape without injury. In this case, however, the hatch sealed with thousands of pounds of force. Ed White didn’t even have time to start the process of removing the bolts before being asphyxiated.

The burnt inside of the command module

Plenty of blame went around and many in the NASA community pointed fingers at North American Aviation for shoddy work. However, this was the most complex and advanced piece of machinery ever created, designed to fly to the moon. Problems had to be expected. Furthermore, NASA vetoed North American’s idea of creating a hatch with an explosive safety feature, an understandable move after Liberty Bell 7, but in retrospect, the explosive hatch would have come in handy for Apollo 1. In the end, the fact that this tragedy occurred on the launching pad and not out in space also allowed investigators to get more information on what happened and make improvements that may saved lives in the future. Despite the horrific tragedy, the goal of landing on the moon before decade’s end – a goal first stated by President John F. Kennedy – would not be compromised and the missions would continue. AS-204 became known as Apollo 1, and the previous three uncrewed Apollo missions, AS-201, 202, and 203, would go unnamed. This led to the program continuing with Apollo 4 in November of 1967.