>> Thursday, January 27, 2011
Yes, I'm still shut down, but this is an important week for NASA, something we all must remember lest it happen again. Today is the anniversary of the Apollo 1 fire and a post I wrote two years ago.
This is a tough week for NASA and for those that care about safety and space. In the space of six days, we have the anniversaries of each of the worst space disasters resulting in loss of life (though we have lost ground support personnel in other accidents): Apollo I, STS-51L (Challenger) and STS-107 (Columbia). It’s a sad time for us, a time to reflect on what we’ve done wrong and on the brave and talented souls that paid the ultimate price for our mistakes.
The sad thing, as I mentioned in a comment for yesterday’s blog, is that all three of these accidents were preventable. Of all the lessons we should be taking home, that is the one we must not lose sight of. There are issues and unexpected bad things that can always hinder us in space, things we can’t necessarily be fully prepared for; we must not add those risks we can correct.
But, as sad as it is to discuss these, they stand as lessons that may have helped us further down the line, that, hopefully taught us things that have saved other lives. If we have learned too late, at least we learned. But those of us who care passionately about the safety of the crew, those of us who are responsible for the lives of others, we must look back on these mistakes periodically, not only to make sure those lessons are still fresh in our minds, but also to remind ourselves why we work so hard to do the right thing. To prevent tragedies like this.
If I’m sometimes critical of our human space program, I have to say that a huge portion of what everyone does is to protect human life. These accidents remind us why that effort is worth it.
Charred crew module interior after the fire, NASA image42 years ago today, on January 27, 1967, the crew of AS-204, which they called Apollo 1, climbed into the crew module for the new Apollo missions, the first involving three crewmembers for a plugs-out test, which was not expected to be hazardous. The module was pressurized to 16 psia, higher than ambient, and was 100% oxygen, which the contractor recommended against. The crew module had a number of known but uncorrected flaws and the crew had expressed concern about fire hazards. The astronauts had also lobbied successfully for an outward opening door, but that design change was not incorporated here. Still, flawed or not, the hope was to successfully pass the test today and launch it three weeks later in February.
At 6:31:07, *before the test had even started*, the first cry of fire came from the cabin. For about 10 seconds, one could hear frantic movements followed by Chafee yelling, “We’ve got a bad fire! Let’s get out! We’re burning up! We’re on fire! Get us out of here!” Then, a scream of pain and the end of the transmission, seventeen seconds after the first report of fire. The crew module ruptured from the pressure and toxic black smoke poured from the module.
It took another eight minutes before they could open the hatch, by which time the fire had gone out. It took 7.5 hours to remove the crews remains, as they were fused in place by the melted nylon of their suits. It was not a fun way to die.
In the end, a number of key factors were called out as potential causes and contributors. The high pressure oxygen environment was very dangerous from a flammability standpoint (”in which a bar of aluminum can burn like wood” according to Wikipedia). There was a wealth of off-gassing flammable nonmetallics like nylon and velcro. Wiring and plumbing was substandard (note that 1407 wiring *design* problems were corrected after Apollo 1) with a stripped and abraded wire near a leaky coolant line (a potential exothermic explosion) but just the static electricity from their suits were found sufficient to have started a fire in that atmosphere. We were not short of smoking guns and no single cause was ever determined as *the* cause.
We were feckless, we were sloppy and we thought that the success with Mercury and Gemini at 100% oxygen made us bulletproof. Astronauts Edward H. White II, Virgil I. Grissom, and Roger B. Chaffee paid the price.
You’ll be pleased to know that nonmetallics are given careful consideration before flight, requiring both toxicity and flammability off-gassing tests (if not a previously flown material). Even the simplest ground tests are done with emergency personnel on site, with procedures for rescuing test subjects practiced and in hand (and that have saved lives since, but that’s another story), a thorough safety review before proceeding. We fly with an air mixture (except in the suits) and wiring and materials are held to very high standards. Materials used, particular “on” the crewmembers must be self-extinguishing (and materials developed for space use are also in use by firefighters all over the world).
But, as we move forward, we must remember these lessons and not get complacent. It’s been a long time since such a thing happened and, especially as we move to commercial human spaceflight, these lessons should be revisited. I hope everyone with the intention of shuttling people into space has read and understood the lessons in this one tragic not-quite-test.
May we never forget.