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Foam Gluing Flaw Killed Columbia Astronauts
Freshly Exhumed writes "Now it can be told: NASA's Columbia Accident Investigation Board has blamed the faulty application of insulating foam for the loss of the Columbia orbiter. From the chief engineer for the external tanks project: '...NASA concluded after extensive testing that the process of applying some sections of foam by hand with spray guns was at fault.' And further: 'It was not the fault of the guys on the floor; they were just doing the process we gave them'."
Just guessing, but:
The main fuel tank (the big cylinder in the center) is filled with liquid hydrogen. It is topped off until moments before launch, and since its boiling point is far colder than 300K, I imagine it gets a bit violent when it touches the "hot" rim of the tank, so some may splash out and dribble down the side of the tank.
As for why it doesn't evaporate immediately, I refer you to the Leidenfrost effect.
Liberal (adj.): Free from bigotry; open to progress; tolerant of others.
Nor are there any tiles, as more than two fool implies.
The foam is sprayed on, and it adheres directly to the External Tank's aluminum substrate (and itself, of course). Some metallic sections of the tank are coated with epoxy before being sprayed. But the process is slightly different on the bipod structure:
The insulated region where the bipod struts attach to the External Tank is structurally, geometrically, and materially complex. Because of concerns that foam applied over the fittings would not provide enough protection from the high heating of exposed surfaces during ascent, the bipod fittings are coated with ablators. BX-250 foam is sprayed by hand over the fittings (and ablator materials), allowed to dry, and manually shaved into a ramp shape. The foam is visually inspected at the Michoud Assembly Facility and also at the Kennedy Space Center, but no other non-destructive evaluation is performed.
-- excerpt from CAIB report vol. 1, p. 51
You can get all the CAIB reports here.
I hold it, that a little rebellion, now and then, is a good thing. -- Thomas Jefferson
Its great to find the point source of the failure, but after reading the report of the committe, it was clear that the real cause of the failure was systemic, going back many, many years.
"Gentlemen, you can't fight in here! This is the War Room!" -- Dr. Strangelove
hydrogen molecules are small, but not all that small. perhaps you're thinking of helium, which can slowly diffuse through sheets of glass etc., though usually not something like steel. helium is way smaller than hydrogen, since its monatomic, not diatomic. and when you're dealing with cryogenics, there are the interesting properties of helium II to worry about...
If you have any amount of a substance, some of it is naturally ionized.
Ionized Hydrogen is just a proton...it's really freaking small and can permeate *anything*.
Hydrogen doesn't leak through the seams of the tank, it leaks through walls.
You can contain this leakage with a static electric field around the whole tank, but there are drawbacks to that too. Think Hindenberg style drawbacks.
MIR operated for three times as long as intended. How is this not impressive?
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Wow, what shitty math. Ok, first you quote 400 km/h: .
The 'Foam' couldn't possibly have been traveling at the 400 km/h when it struck the Columbia's wing, as claimed. Consider. .
Then you quote 400 km/second:
The Shuttle lifter, while enormously powerful, certainly doesn't accelerate at 400 km/second.
I think we can all argree the shuttle doesn't accelerate at 400 km/SECOND.
That, and your accelerations are listed as velocities. Of course, the fact that air resistance could have played a role in accelerating the foam into the shuttle probably never crossed your mind. Finally, the shuttle is not an aircraft. It is primarily a space craft. Space craft tend to be "fragile." The heat shield tiles tend to be "fragile" as well.
Try again, with more math.
That's right. All your base.
that ABC has messed up the story. What is really getting into the voids is water vapor or nitrogen. Either that or the tank is so poorly constructed that dangerously flammable liquid hydrogen is leaking out, in which case it is a wonder that the shuttle hasn't exploded right on the launch pad.
"I'm so moist I'm sticking to the leather." -Kermit the Frog on The Late Late Show
What happens to a very draggy chunk of low density foam in a supersonic stream of air? It will rapidly decelerate, right?
Imagine you impale a cheap styrofoam cooler on your car's hood ornament and head out on the highway. At 70 MPH, the cooler pops off the hood ornament. What happens? Does it keep coasting along with little relative velocity with respect to the car? No. It smashes into your windshield at close to 70 MPH. Whether the car is accelerating or not has almost no effect on the outcome. It's the rapid deceleration of the foam that causes the significant relative velocity when it strikes the car. Only the relative velocity is important. Sorry the NASA engineers confused you by not suspending a block of foam motionless in the air and hurling a section of wing at it.
As for the bulk of your post, containing that half baked ranting, UFOlogy and conspiracy theories, I'd have to say you get the tin foil hat award for the rest of this century. I imagine you with your tinfoil hat, wrapped in tin foil from head to foot, in a titanium submersible on the bottom of the ocean. And the mind control waves still get through. All that trouble, and all you really need to do is...
UP YOUR DOSAGE.
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