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Apollo 1
Last year we looked at the Challenger. This year: Apollo 1. On January 27, 1967, the three-man crew of Gus Grissom, Roger Chaffee, and Ed White who were in training for the first Apollo flight were asphixiated in their capsule during a training exercise. The men reported communications glitches prior to the disaster, and it is believed that a spark in their pure-oxygen atmosphere quickly started an unstoppable blaze, consuming the many flammable components in the capsule. There were three hatches between the men and the outside of the capsule, which were not designed to be opened in less than 90 seconds. In addition, it is doubtful that the astronauts could have opened the internal hatch at all since pressure inside the spacecraft rose rapidly after the fire, exceeding the capacity of the pressure-equalization valves. Future designs were modified to remove most of the flammable components from the crew area and include a new quick-opening hatch. NASA has a retrospective.
Everyone who saw the original HBO series 'From the Earth to the Moon' knew that. It is very well done, and you should go check it out if you haven't seen it. I'm not sure if you can rent it as it's about 6 VHS tapes. Maybe you can get it on a DVD format now?
At least with the Challenger launch, the pressures from on high to keep schedule with the high profile crew (Mrs. MacAuliffe) must have been rather high, and not just from the immediate supervisors to the O-ring managers. The launch was a big media event, and the pressures of delivering on the promise of a historic launch date probably swayed more than a few otherwise clear heads at NASA.
Yes they asphyxiated. Their deaths were caused by the inhalation of the fumes from the burning surfaces in the capsule. The only part of their bodies that were burned were the exposed surfaces (hands, faces) under their suits they were completely unscathed.
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Striving to put right what once went wrong, and hoping each time that his next leap, will be the leap ho
Where did you get this idea? The question of whether or not the external pressure on the capsule is 1ATM or 0ATM is moot, because the whole idea of hatches and airlocks is to keep everything on the inside of the capsule in. In fact, the astronauts would have an EASIER time getting out here on earth because there would be a smaller pressure differential to work against in opening the airlock than there would be enroute to the moon. You can get a similar experience by trying to open a door in a facility with intentional pressure differences, such as a lab. If the door opens inward to the office, and the lab is kept at a lower pressure than the hallway (common precaution for vaporous chemicals and biotoxins), the door will be easy to open as hallway air rushes in to equalize the pressure. But what if your lab were pressurized higher than the hallway? The door would be harder to open, because you would not only have to work to open the door, but also work against the air trying to rush out (and pushing the door shut as it does so!)
So now that we've got that little bit of science out of the way, the next problem with your "analysis" is that a difference between 1ATM and 16.7PSI does not result in a *HUGE* difference in available O2. For the clueless, 1ATM=14.7 PSI, or a difference of just 2PSI. I'm not going to do the math here, but needless to say, a balloon has a higher PSI than that capsule did. Are you suggesting that a balloon filled with O2 will just smoulder in space? I think not.
The problem of using a pure O2 mixture is simply because O2 is such a volatile thing that the smallest spark can ignite the closest flammable object (wire insulation, if memory serves), and once that's started, anything else in the area is a juicy target for more combustion fun.
I suspect that one of these choices is incorrect. Correct.
The reason the hatches took no less than 90 seconds to open is because NASA wanted to prevent another Liberty Bell 7 incident (MR-4) where the hatch supposedly blew off prematurely.
You're referring to explosive hatch bolts -- but modern journalists have speculated that a pad leader would not have have allowed an explosive bolt system to be armed during an apparently safe countdown test. The more serious design flaw in the hatch was the fact that it opened inward -- a tradeoff to save weight since the cabin pressure kept it closed, but which sealed the astronauts inside when the fire broke out.
Toronto-area transit rider? Rate your ride.
what many of you that are commenting on are failing to realize is that you are using your perspective of "today" and not from that time. My dad was part of the apollo project and specifically was part of the accident and redesign team that focused on all aspects of the electrical system. I had the fortune to visit the launch pads and facilites in florida where he worked shortly before he passed away. The hatch may have prevented them from getting out, but fire in the capsule was not considered a possibility at that time. It was an engineering choice. After the accident they went through the entire design, testing, production phases and made significant changes on everything. the cause was a short in the oxygen panel in a rarified oxygen atmosphere. It was a flashfire that they could not have escaped even if they could have My dad was very proud to have helped to redesign the entire electrical system, but he also pointed out that they (engineers) took the time to go through every system on the entire craft. All the engineers took the acident personally and went out their way contribute to the improvements. It was a time of unknowns and great challenges and shows the quality of the human spirit in the face of adversity.
Actually, the pressure differential is correct in your explanation. The capsule doors were built to open in space, where the outside pressure would be close to 0 and the inside pressure would be close to 1ATM, however, that same fact is used to actually keep airplane doors from opening at high-altitude. The fact is that they are built in such a way that a higher pressure inside than outside makes it harder to open the doors. A lab door is not really as relevant in this arguement.
The committee can only conclude that NASA's long history of successes in testing and launching space vehicles with pure oxygen environments at 16.7 p.s.i. and lower pressures led to overconfidence and complacency
North American was told that the CM would be pressurized at 5psi pure oxygen, which was true during flight. It was fireproofed to these specs. Nobody informed them that launch pressure was sea level. The CM was definitely not fireproof at that pressue.
Er, I've got to respond to a few of the points raised above...
Where did you get this idea? The question of whether or not the external pressure on the capsule is 1ATM or 0ATM is moot, because the whole idea of hatches and airlocks is to keep everything on the inside of the in. In fact, the astronauts would have an EASIER time getting out here on earth because there would be a smaller pressure differential to work against in opening the airlock than there would be enroute to the moon.
The capsule atmosphere after launch was actually much less than sea level (5 psia), so the external pressure would make a significant difference. The point of pressurizing to greater than atmospheric during the test was to simulate the pressure difference between the capsule and outside, not the true internal pressure to be used after launch. In fact, since the capsule was designed to contain internal pressure greater than than outside, it probably wouldn't have been structurally possible to hold a sub-atmospheric pressure inside.
So now that we've got that little bit of science out of the way, the next problem with your "analysis" is that a difference between 1ATM and 16.7PSI does not result in a *HUGE* difference in available O2. For the clueless, 1ATM=14.7 PSI, or a difference of just 2PSI.
Bzzzzt. For the clueless, what is generally considered 1 atm (the stuff we breath) consists of about 79% nitrogen. Compare this with 16.7 psi pure O2, and I think you'll see a difference.
I've got no idea why the original post of this thread is now rated "Troll" because the poster is essentially correct in many details, unlike the previous post. If the pressure in the capsule is a constant "few" psi over the outside, there is in fact a "HUGE" difference in the flammability and available oxygen inside when it is pressurized on the ground versus in space. Things are going to be way more flammable at an absolute pressure of 16.7 psi O2 than at the flight level of 5 psi O2 in the cabin. In fact, in normal air, the oxygen partial pressure is about 0.21*14.7 = 3 psi. Imagine having 5x more oxygen available! Anything not already completely oxidized will want to burn (and fast!), even materials that are essentially fire-proof in air and low O2 pressures.
Interestingly enough, in order to keep with the desired "20% oxygen" atmosphere of the capsule, NASA decided that they would create a total O2 environment, but at only 20% of the pressure to give the same net result. Unfortunately, of course, this created a COMPLETE oxygen environment which allowed the fire to spread wildly. From then on (the next manned mission would be Apollo 7) and including today's Shuttle, the compatment contents are kept at 20% oxygen by means of an air consisting of 20% oxygen and 80% nitrogen.
Apollo 7 and on also gave the astronauts complete and independent use of an emergency hatch opener, a lesson tragically learned from Apollo 1.
I believe the reason was the same that deep sea divers use pure O2, it was to prevent the bends
Not quite. Divers almost never breath pure O2 in the water. Oxygen under pressure is toxic, and can cause seizures (bad when you're under water). The only exception to this would be what's called an oxygen rebreather. It's a closed circuit breathing system using pure O2. CO2 is scrubbed out with a chemical absorbant. The main feature of these systems is no exhaust bubbles. They were popular with military frogmen for sneaking into harbors and the like during WWII and sometime after, but they could only be 'safely' used shallower than about 30 feet. Deeper than that is asking for trouble.
Nowadays closed circuit breathing systems use mixed gases for breathing and computers to maintain the proper O2 proportion.
When divers do breath pure oxygen is out of the water in a decompression chamber. The idea is to 'wash' (not really what's happening, but the simple way to expain it) the nitrogen out of the divers tissues quicker than breathing air which is 80%+ nitrogen. It's not so much to directly prevent decompression sickness as it is to shorten decompression times.
Fire is always a big concern when doing this, minimum combustibles in the chamber, absolutely no grease or oil on anything and usually special breathing masks that dump the exhaled gas outside the chamber. I used to be in that biz.
Tog has an excerpt of the Challenger chapter of that book:
http://www.asktog.com/books/challengerExerpt.html
I think what you forgot is that the Soviets had the chance to really take a step closer to a moon mission had the Soyuz 1 mission worked. Unfortunately, the Soyuz 1 capsule suffered all kinds of system failures during its flight, which resulted in a re-entry that resulted in a tangled parachute line. This caused the capsule to literally crash into the ground, killing the cosmonaut on the flight.
The Soviet moon program never really recovered from that tragedy, because the a derivative of the Soyuz spacecraft was to have flown to the moon. Realizing its limitations, the Soviets decided to use Soyuz as an Earth-orbiting spacecraft, which has worked well to this day.
Hmmm, no-one seems to have mentioned Andrew Chaikin's excellent Apollo resource A Man on the Moon - you can read the first few pages of the section on Apollo 1/AS201 using amazon's "Look Inside" feature. If you can't abide to buy anything from amazon for whatever reason, the ISBN is 0140272011 for the most recent paperback edition, and 0783556799 for the bloody expensive illustrative commemorative boxed set edition.
Probably one of the best, most accessible books on the subject of Apollo.
neuro at well dot com (when I post, it's my opinions, no-one elses)
I wasn't sure what the pressure was when I replied, I knew it was less the 1 atmosphere however. It was meant to be about 5psi.
5psi cabin pressure is fine if natural atmosphere. It's within the levels that pilots can just about cope with in sudden decompression, although requires an oxygen mask within a short period of time. It does not cause their eyeballs to explode or anything, and has no effect on the body bar the suffocation (even in space, people would not explode). High mountains have less pressure than this.
If there is 2psi of pure oxygen, then it is perfectly possible to breath, especially if the pressure is brought down from slightly higher (IIRC it was lowered after launch, and also the suits had oxygen feeds directly, increasing concentration in the locality of the astronaut).
There is approximately the same amount of oxygen (in moles, amount of molecules) in a 1 ATM natural atmosphere as there is in a 5psi pure oxygen atmosphere. The concentrations were similar. However, on the ground, the concentration was very, very much higher.
This resulted in a very bad, quick fire. The overpressure meant that they had no chance of survival.
Simply, if this had happened in space, they would have had time to react and extinguish the fire before it reached such an extent. Granted, they would be slightly worse off if they had evacuated.