No, this pressure is not significant. Its around one or 2 atmosphere’s increase. (to 2 or3 ? ) . Its merely the pain you feel while diving. People regularly dive to 40 metres deep, which is around 4 atmospheres higher than surface level pressure. (total of 5 atm )… So whether the readings were increase or absolute, its clearly not above 5 atm in any case.
5 Atm will burst your ear drum, if you don’t consciously open the eustachian tube… but thats not deadly.
16psi pure oxygen in a hand-wired, very complex piece of electrical equipment. What could possibly go wrong? Ever seen one of those experiments where you blow pure oxygen at a flame?
It was 20 years ago but I remember that part of the book too (before the movie tie-in the book was called Lost Moon btw). The guy who checked the skin on the leg was a fire fighter, which is why he knew to do that. And although they did die from asphyxiation, they were exposed to enough heat for enough time (it took 15 minutes to finally get the capsule open) that their bodies *were *significantly burned.
In space there’d be a vacuum outside and about 5 psi pressure inside the capsule. Because of a convenient quirk of gas pressure physics breathing pure oxygen at 5 psi is the same as breathing 40% oxygen (i.e. normal air) at sea level’s 15 psi. But to simulate the 5 psi pressure differential on the ground meant they had to pump the capsule up to around 5 psi above sea level pressure, and to simplify things they still used pure oxygen for this.
After Apollo 1 they changed to an oxygen/nitrogen system while on the ground, then it gradually changed to pure O[sub]2[/sub] at low pressure once in orbit.
Pure O2 is crazy shit.
Back in college on one occasion, we had trouble keeping a charcoal grill burning during the dead of winter; the cold air reliably sucked the life out of it. The next time, we got a bottle of O2 from a welding shop and set it up to trickle-feed into the charcoal. One match in one spot on one piece of charcoal caused it to sputter and spark furiously, and every spark that landed on another piece of charcoal caused it to similarly begin burning vigorously. It became a challenge to set an O2 flow rate that didn’t rapidly incinerate the food, and for safety’s sake we move the grill off of the deck and onto solid ground a few feet from the building, knowing that there was the potential to burn/melt through the steel bowl of the grill itself.
Around the same time there was a guy at Purdue who made a name for himself lighting charcoal grills with liquid oxygen. As I remember it, he started with 60 pounds of charcoal that had a lit cigarette on top for ignition. Pouring on the LO2 resulted in 40 pounds of charcoal burning away in three seconds, and the remaining 20 pounds being ready to cook. In doing this stunt on cheap little grills, the grill itself typically incinerated. The lit cigarette was said to be critical for getting the fire going as the LO2 was being poured on: if you soaked charcoal in LO2 and THEN lit it, you basically had a pile of dynamite going off and could kiss your ass goodbye.
If you spill LOX on asphalt, merely walking across it can cause an explosion!
IIRC, studies after the fire showed that nominally fireproof materials became flammable after being soaked in pure oxygen for a time (as running ground tests would do).
The Mercury and Gemini missions all did the same tests with pure oxygen atmosphere, and none of them burned. It adds a lot of weight and complexity to a craft to be able to operate with mixed air on the ground and pure oxygen in space, so they made a trade study and decided to use only pure oxygen.
So, like shuttle’s o-ring partial burn throughs, NASA figured there was no issue and kept doing things the way they always had. It turned out that it wasn’t that the risk was not there, it’s that they got lucky before.
Even high purity hydrogen peroxide will ignite on hitting asphalt (don’t ask me how I know this).
I was the safety guy at NASA’s RETF (Rocket Engine Test Facility) at NASA Glenn in the 1980s. We ran 3000-4000 psi supercoooled LOX in our system. If things went wrong, the stainless steel piping lit off like a Roman candle. We are talking a 4" pipe with 1" thick walls burning so fast you could see it getting shorter as you watched.
I sat in the ominously named Termination Room, a hardened concrete, steel clad room 40 feet from the test stand. I had a great view of the engine through 40 panes of bullet proof glass. I had the abort button, but I waited until the guys in the control room (a quarter mile away) yelled to abort. Heck, they were still taking data.
Before I was assigned there, they ran FLOX, Fluoridated Liquid Oxygen, just for those times when LOX wasn’t enough.
Dennis
From The Earth To The Moon: Apollo 1
The witness testifying is Frank Borman, the astronaut representative assigned to the Apollo 1 Accident Review Team.