Relay-Version: B 2.11 6/12/87; site scorn Path: uunet!shelby!bloom-beacon!daemon From: wdstarr@athena.mit.edu (William December Starr) Newsgroups: alt.folklore.urban,sci.aeronautics Subject: the Apollo 1 fire (pure oxygen at 16 psi) Message-ID: <1990Jul20.151714.19422@athena.mit.edu> Date: Fri, 20 Jul 90 08:17:14 PDT References: <90199.165411DOUG@ysub.ysu.edu> <2370004@hpdmd48boi.hp.com> Sender: daemon@athena.mit.edu (Mr Background) Organization: Northeastern U. School of Law Lines: 159 Xref: scorn alt.folklore.urban:2796 sci.aeronautics:1282 In-Reply-To: jeffw@hpdmd48boi.hp.com (jeff waldeck) [Posted to a.f.u. in the full realization that I'm probably violating the group's charter by actually posting facts...:-) X-posted to sci.aero on the chance that some folks there might find it interesting.] In article <2370004@hpdmd48boi.hp.com>, jeffw@hpdmd48boi.hp.com (jeff waldeck) said: > Wasn't the fire caused by an electrical short that burned extremely > fast because of the pure oxygen they then used in the cabin? I seem > to remember that the time elapsed from first indication of trouble > to the end was measured in seconds... :( That's correct. In 1974 Michael Collins, the third man on the Apollo 11 mission, wrote an excellent autobiography called "Carrying the Fire," in which he wrote about his Air Force and NASA careers. This is what he has to say about the fire in the Apollo command module numbered 012, the vehicle which was scheduled to carry Gus Grissom, Ed White and Roger Chaffee on the Apollo 1 flight: -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- On Friday, January 27, 1967, the astronaut office was very quiet, practically deserted, in fact. Al Shepard, who ran the place, was off somewhere, and so were all the other old heads. But someone had to go to the Friday staff meeting, Al's secretary pointed out, and I was the senior astronaut present, so off I headed to [Deke] Slayton's office, note pad in hand, to jot down another week's worth of administrative trivia. Deke wasn't there either, and in his absence, Don Gregory, his assistant presided. We had just barely gotten started when the red crash phone on Deke's desk rang. Don snatched it up and listened impassively. The rest of us said nothing. Red phones were a part of my life, and when they rang, it was usually a communications test or a warning of an aircraft accident or a plane aloft in trouble. After what seemed like a long time, Don finally hung up and said very quietly, "Fire in the spacecraft." That's all he had to say. There was no doubt about which spacecraft (012) or who was in it (Grissom-White-Chaffee) or where (Pad 34, Cape Kennedy) or why (a final systems test) or what (death, the quicker the better). All I could think of was, My God, such an obvious thing and yet we hadn't considered it. We worried about engines that wouldn't start or wouldn't stop; we worried about leaks; we even worried about how a flame front might propagate in weightlessness and how cabin pressure might be reduced to stop a fire in space. But right here on the ground, when we should have been most alert, we put three guys inside an untried spacecraft, strapped them into couches, locked two cumbersome hatches behind them, and left them no way of escaping a fire. Oh yes, if the booster caught fire, down below, there were elaborate if impractical, plans for escaping the holocaust by sliding down a wire, but fire inside the spacecraft itself simply couldn't happen. Yet it had happened, and why not? After all, the 100 percent oxygen environment we used in space was at least at a reduced pressure of five pounds per square inch, but on the launch pad the pressure was slightly above atmospheric, or nearly 16 psi. Light a cigarette in pure oxygen at 16 psi and you will get the surprise of your life as you watch it turn to ash in about two seconds. With all those oxygen molecules packed in there at that pressure, any material generally considered "combustible" would instead be almost explosive. And combustible material -- books, clothing, supplies -- there were aplenty, also plenty of ignition sources. There was supposed to be none of the latter, but let's face it, the inside of a Block I spacecraft was a forest of wires, a jungle which had been invaded over and over again by workmen changing, and snipping, and adding, and splicing, until the whole thing was simply one big potential short circuit. -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- [a bit later in the book, Collins writes about the 012 investigation results and puts forth one of the most cogent arguments in _favor_ of nitpicking paperwork that I've ever encountered:] ...it became increasingly obvious that the fire in 012 was not simply a one-time freakish occurrence but indicated a generic weakness in the command module family. The first mistake was the environment -- pure oxygen at 16 psi. The second was the abundance of combustible material exposed to that highly inflammable environment. Third, and most insidious, was the lack of an iron-clad system for controlling last-minute changes to the spacecraft; it seemed that too many changes had been approved and those too sloppily executed. The investigating board that spent months examining the charred carcass of 012 never did determine what triggered the fatal spark, but they discovered something even worse -- that there were scores of possible sources, and that the mound of paper work which accompanied the spacecraft was not a completely accurate representation of the true condition of the vehicle. It appeared that some work had been done that never showed up in the paperwork; on the other hand, some jobs had been recorded but not properly finished. There is a facetious saying in the plane business to the effect that not until the weight of the paper work equals the weight of the airplane will it be cleared for takeoff. In the space business, paper the _the_ most important material. Without paper, chaos results, and no one knows which jobs have been talked about and not performed, and which performed but not talked about. This is particularly true in the harried, hurry-up, three-shifts-a-day environment that invariably preceded a manned space flight, especially the first one in a series. The midnight shift, finding itself with an exposed wire bundle fifty-six wires thick, may just splice into the wrong one unless the accompanying paper work has been kept to perfection by the previous shift. -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- [and mention of the subsequent redesigns and changes in materials:] The most difficult job was replacing combustible material with nonflammables, especially for garments, towels, food bags, and other personal gear. Practically any substance will burn if exposed long enough to a sufficiently hot flame in the presence of abundant oxygen. Even stainless steel burns readily in pure oxygen. The exterior layers of the Gemini and early Apollo pressure suits were made of Nomex, a high-temperature nylon fabric which had to be heated to over 700 degrees F to burn, and then it burned slowly; but it was replaced as a result of the fire with Beta cloth (woven glass fragments). Glass underwear can be a bit scratchy, and Beta cloth as an outer garment wears out very rapidly, resulting in miniature glass particles floating free throughout the cabin, where they can be inhaled into the lungs. So Beta cloth should be coated with something, such as Teflon. Thus, what seems like a simple problem escalates. Each new material considered had to be subjected to exhaustive testing, and of course, it was not only suit coverings which were to be replaced, but virtually any exposed component inside the command module. It quickly became apparent that although solutions were fairly straightforward, it was going to take one hell of a long time to implement them. In addition to new materials, new mechanisms were required. The side hatch, for example, needed redesign to permit swift egress: there were actually two hatches, and the inner one had to be laboriously removed using a torque wrench, exposing the outer one, which could be removed only after the heavy inner hatch had been set aside. The two were combined into one, and the latching mechanism was vastly simplified. All these things took time, and our hopes for getting three manned flights off in 1967 quickly evaporated. A year's delay at best, said the smart money, but it ended up being closer to two years. -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- [For the record, the first manned Apollo flight, Apollo 7, lifted off on October 11, 1968, over twenty-one months after the Apollo 1 fire. Incredibly, it was only a bit over nine months after that that Armstrong and Aldrin landed on the Moon while Collins remained in the command module in lunar orbit.] -- William December Starr