Apollo 1 The Cause

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Apollo 1
The Investigation

In the aftermath of the fire three questions hung in the air, what had caused the fire, who was responsible for such a tragedy and could NASA recover from such a disaster in time to achieve the moon landing before the end of the decade?

The Apollo 1 crew in California reviewing their flight plans.

Gene Kranz wrote "If there was anything that could be retrieved from this tragedy, it was evidence - it was right there in front of us on Pad 34. We had a chance to discover the cause of the fire before another spacecraft was put at risk".

The investigation began with the burnt out Command Module, CM 012, being examined alongside the Command Module that had been designated to Schirra's Apollo 2 flight. Bad workmanship was found in both spacecraft and the investigation team even found a wrench behind one of the panels inside CM 012 that had been left behind by a workman.

The search for clues to the fire went further and CM 017, assigned to the first unmanned launch of the Saturn V rocket, was also inspected leading to a list of over 1400 discrepancies being noted with that spacecraft.

Fire damage to the exterior of CM 012.

A guard stands on watch over the spacecraft's heatshield.

The various inner parts of the Command Module are laid out for inspection into the cause of the fire. Note the two hatches on the right hand tables, the blackened inner hatch can be seen, dreadful proof of the conditions inside the spacecraft during the moments after the fire started.

North American rebuffed the claims of being incompetent saying that NASA had continually made changes to the spacecraft specifications and had tried to tie them down to ever tightening deadlines. They cited that the rule of having no more than 500 sq inches of velcro inside the spacecraft had been ignored and that CM 012 had over 5000 sq inches of velcro in it.

They also stated that they had not designed the spacecraft to be used with over 16 psi pure oxygen as it's normal operating atmospheric pressure.

NASA counted by pointing out that the fire had occurred during a test and that such an high internal pressure would not be used at any other time and so the recriminations continued as each side tried to shift the blame.

Finally on 27th March 1967 the disassembly of CM 012 was completed and although the exact cause of the fire could not be determined, the investigation panel put forward their findings.

This diagram shows the Command Module (grey) with the inner cockpit pressurised with 100% oxygen (green).

Inside the cockpit can be seen the main instrument panel over the astronaut's couches.

Covering the Command Module (CM) was the Boost Protection Cover (BPC) this protected the spacecraft's exterior during ignition of the escape rocket, situated above the CM, when it was jettisoned during launch.

To exit the CM the CM Pilot (CMP) had to reach above his head and open six bolts on the inner hatch (red) and then open the outer ablative hatch (blue). The inner hatch maintained an air-tight pressurised environment for the astronauts to work in whilst the outer hatch was part of the protection from the heat of re-entry, it's ablative covering dispersed the heat that built up during the fiery return to earth. Finally the BPC hatch (gold) was secured in place after the astronauts had entered the spacecraft and the cockpit had been pressuried, for the test that day it had not been locked in place.

The two parts of the spacecraft can be seen in these photos of it in storage at the Langley facility below, the inner cockpit is on the left and the outer heatshield is on the right. On the 17th of February 2007 the spacecraft was resited to an environmentally-controlled facility at the Langley Research Center in Hampton, Va.

So what had been the circumstances that had led to such a disastrous fire? On the day, the astronauts had entered the spacecraft and the inner and outer hatches had been closed and locked in place. The spacecraft's internal atmosphere had pressurised at 16.7 psi of pure oxygen to simualte the conditions in orbit of around 5.5 psi. The high pressure had been necessary to counter the atmospheric presuure at sea level of 14.7 psi, if the difference between the outside pressure and that of the the pressure inside the spacecraft was greater than 2 psi then the cockpit could implode. This had resulted in two problems straight away.

Firstly, the pure oxygen had permeated everything inside the cockpit over a number of hours and oxygen at such high pressure is corrosive and extremely combustible and made the 70 lbs of flammable material inside a fire hazard. During tests conducted after the fire, velcro literally exploded into flames under such conditions and even aluminum burnt whilst the solution in the cooling system gave off a thick black smoke. Secondly, the inner hatch once in place was impossible to remove from it's postion because of the high pressure bearing upon it.

The three men were locked inside a spacecraft with a hatch that would not budge and an atmosphere of pure oxygen at a dangerous pressure. Lee Atwood, President of the CM contractors North American, was staggered to find out the details of the test for spacecraft AS 204 that January day. Hindsight makes some actions seem unbelievable but "locking those men in a spacecraft, pumping 16 lbs of pure oxygen on them and telling them to operate complicated electrical equipment" as he would later say was beyond belief.

Gus Grissom is photgraphed in his couch during a visit to the contractors to inspect the Apollo spacecraft. In the bottom right of this photo bundles of bare wires can be seen.

After being taken apart and then neglected for many years the poor condition of the interior can be seen in this image of the same view of that on the left.

The conditions inside the spacecraft were dangerous but further circumstances would lead to the fire. Continual design changes made by NASA had led to, in Donald Slayton's words, "sloppy workmanship", and errors and faults had crept into the 15 miles of wiring inside CM 012. At a point behind a panel on Grissom's side, the insulation on a couple of wites had frayed and could have caused an electrical arc. Below these wires ran an aluminium tube carrying a cooling glycol fluid that turned into flammable fumes when it came into contact with air.

The fact that the spacecraft was continually being worked upon most probably resulted in movement and stress upon this tube and could have caused a leeak of the coolant which then came into contact with the electrical arc from the damaged wiring. The tubing and wiring were not originally planned to meet at this point but after incessant chanes in it's design they now came together in spacecraft 012. To add to the problem, netting was located nearer than it should have been to the damaged wires.

The investigation panel theorised that a spark from the frayed wiring reacted with the fumes and caused a hot spot in the netting that grew in size and temperature until it burst into flames.

A foam pad left on the floor of the spacecraft and the velcro soaked in 100% pure oxygen would have exploded into flames and these would have spread from Grissom's side of the spacecraft to the opposite side surrounding the three men in fire.

The astronaut's spacesuits were made of materials with a resistance to temperatures up to 700 degrees Fahrenheit, the internal heat during the fire was above their melting point.

After a few seconds the men's oxygen hoses would have burnt through and they would have become unconcious in a very short space of time.

The internal temperature soared to over 2500 degrees Fahrenheit and the cabin pressure reached twice the atmospheric pressure at sea level. In just over 15 seconds after the first report of fire the spacecraft's inner hull ruptured sending flames jetting out into the White Room.

During the investigation of the fire a letter came to light that had been sent in early October 1966 by Hillard W. Paige, the Vice President and General Manager of the Missile and Space Division at General Electric. The letter had been sent to Joe Shea, the Apollo Program Manager, and it expressed the concerns felt by paige towards the 100% oxygen atmosphere. He had wrote that it was unwise to be influenced by the success of the 100% oxygen environment for Mercury and Gemini and he added that "The first fire in a spacecraft may well be fatal".

Not only did the fire result in a complete re-shuffle of crews and mission objectives, it also meant that the spacecraft and the way it was constructed had to be made far safer. Slayton questioned the decision to fly the Block I spacecraft at all saying they were rushing along with the program too fast. The Lunar Module was not ready and perhaps having a gap between the last Gemini mission and the first Apollo mission would have been a better idea. This time between the two programs could have given everyone a breathing space and Apollo could have started with the Block II spacecraft. In the end everyone got a breathing space but three men died in a sub-standard spacecraft in order to get it.

Would America have been able to land a man on the moon before the end of the decade if the fire had not occurred? Well the breathing space after the fire allowed for the spacecraft to be perfected so that once Apollo got under way it wasn't continually held up by faults appearing during actual missions, the Apollo 1 fire had reduced the chances of this happening.

As Chris Kraft later said, "There was enough wrong with the spacecraft that without the fire, we might not have made Kennedy's deadline at all. We'd have flown, found problems, taken months to fix them, flown again, found more problems, taken months...We might not have landed on the moon until 1970 or '71."

The sacrifice of Grissom, White and Chaffee should always be remembered as one of the reasons for the ultimate success of the Apollo Program and that it allowed Armstrong and Aldrin to land at Tranquillity Base, thus fulfilling Kennedy's challenge.

The same view of the spacecraft's interior seen before and after the fire. During the investigation the spacecraft was taken apart so that the cause of the fire could be determined. Note the oxygen hose outlet at top left.

Grissom's side of the spacecraft, note the blackened window at top left. It was determined that it was on this side of the spacecraft that the fire had started.

The re-design of the Command Module resulted in a far safer spacecraft with a new and easier to open one-piece hatch and better safety procedures including eliminating the pure oxygen atmosphere inside the spacecraft during the countdown period, although the crew still had 100% oxygen flowing through their spacesuits.

The 18 months before the launch of Apollo 7 were put to good use by NASA and the contractors building the hardware to catch up on the tight production and procedure schedules.

Altogether 15 Command Modules spent a total of over 281 days in space with only minor problems, testimony to the re-design of the Apollo spacecraft.