Investigators: Shuttle's Exterior Pierced During Fiery Descent

WASHINGTON (AP) - The space shuttle's skin almost was certainly pierced, allowing superheated air inside the left wing and possibly the wheel compartment during Columbia's fiery descent through Earth's atmosphere, investigators said Thursday.

In its first significant determination, the accident investigation board announced that heat damage from a missing tile would not be sufficient to cause unusual temperature increases inside Columbia minutes before it disintegrated. Sensors detected an unusual heat buildup of about 30 degrees inside the wheel well before the accident.

The board determined those increases were caused by the presence inside Columbia of plasma, or superheated air, with a temperature of roughly 2,000 degrees. It said investigators were studying where a breach might have occurred to allow plasma to seep inside the wheel compartment or elsewhere in Columbia's left wing.

The announcement focused renewed attention on possible catastrophic failures inside the wheel compartment that may have attributed to the Feb. 1 breakup that killed seven astronauts.

Officials are not sure where a hole might have opened in Columbia's skin, NASA spokesman James Hartsfield said. But he said the leading edge or elsewhere on the left wing, the fuselage or the left landing gear door were prime candidates.

"Any of those could be potential causes for the temperature change we saw," Hartsfield said. "They do not and have not pinpointed any general location as to where that plasma flow would have to originate."

The board dismissed suggestions Columbia's left landing gear was improperly lowered as it raced through Earth's atmosphere at more than 12,000 miles per hour. NASA disclosed earlier Thursday that a sensor indicated the gear was down just 26 seconds before Columbia's destruction.

If Columbia's gear was lowered at that speed - and in those searing temperatures as the shuttle descended over Texas from about 40 miles up - the heat and rushing air would have sheared off Columbia's tires and led quickly to the spacecraft's tumbling destruction, experts said.

Officials said they were confident that unusual sensor reading was wrong. Tires are supposed to remain raised until the shuttle is about 200 feet over the runway and flying 345 miles per hour.

Two other sensors in the same wheel compartment indicated the gear was still properly raised, they said.

While Columbia's piloting computers began almost simultaneously firing thrusters struggling to keep wings level, officials said a mysterious disruption in the air flowing near the left wing was not serious enough to suggest the shuttle's gear might be down.

The investigating board concluded that its research "does not support the scenario of an early deployment of the left gear."

NASA also confirmed that searchers near Hemphill, Texas, about 140 miles northeast of Houston, recovered what is believed to be one of Columbia's radial tires. A spokesman was not immediately sure which of the shuttle's six tires was found.

The tire was blackened and sustained a massive split across its tread, but it was impossible to know whether the tire was damaged aboard Columbia or when it struck the ground.

The board's announcement came one day after NASA released e-mails showing midlevel safety engineers in Virginia and Houston considered the risks of tires bursting inside Columbia's belly from heat damage.

Robert H. Daugherty, responding to an inquiry from Johnson Space Center, cautioned in one of those e-mails that damage to insulating tiles near the landing gear door could cause one or more tires inside to rupture, perhaps ending with "catastrophic" failures that would place the seven astronauts "in a world of hurt."

Ret. Admiral Harold Gehman, who heads the panel investigating the Columbia accident, called Daugherty's concerns "one of the many, many interesting leads that we have."

Something happened at the junction of the wing and fuselage according to the sensors.

Seperate these two things: cause and effect - and you're on your way to understanding just what went on during the re-entry phase to Columbia's flight.

The cause: a failure in the TPS (Thermal Protection System) due to a) loss of tiles or b) a loss of an element in the Leading Edge Sub Subsystem -

- "LESS" - the wing's leading edge which requires *special* materials -NOT tiles- that will hold their shape under high applied physical forces as well as withstand high temperatures at the same time ...

Loose several tiles or a part of the LESS - and during reentry hot plasmatic gases will enter the wing and begin to 'eat' away at the Aluminum and wiring and anything else it wncounters ... this is the effect of one of the the above causes ...

I think I see. Damage during launch should have caused some deflection of the flight path off of nominal. Once they have left the atmosphere and gone into orbit, of course there isn't enough air to have any noticeable effect aside from a slight drag. It's that small drag that would bring the ISS down in a few months if it weren't reboosted with the Russian resupply module motor or the Space Shuttle motor. But above 50 miles there isn't enough air to use for aerodynamic purposes.

50 miles is considered outer space for that reason. When the X-15 rose above 50 miles, the wings were totally useless and they had to use reaction thrusters to control the attitude of the plane.

But would the damage have been enough to take the wing apart during launch at some high altitude? Probably not since the speed wouldn't be particularly high while the Space Shuttle is still in the air. It's nothing like re-entering the atmosphere at the 50 mile altitude at 18,000 mph.

They are only used for one or two landings.

My recollection from reading and searching last week is the tires are used once ... and if inflated to 300 PSI 'on the ground' the 'pressure' difference the tires would see from sea level (sea level = approx 14.7 PSI) and the pressure at altitude would represent a mere drop in the bucket -

- tire pressure measured on the ground: 300 PSI guage or 314.7 PSI absolute, in space 'guage' and absolute would be the same or 314.7 PSI ...

I think we are just argueing for show.
It is to early to know what happened.
I don't think NASA is pulling a Warren Commission at this time.
I do find it hard to believe the foam problem, a known problem, finally caused it to explode.
I am not ruling it out, but it seems doubtful.
The thing blew up over my house, it was a very powerful explosion and shook the ground.
Granted this wqas long after initial breakup.
I don't discount the fact it was the heaviest payload ever, more stress and harder to control if it does gets out of shape.

Tell me you're kidding. They launch and land with inflated tires, knowing that leakage, pinholes, etc in the wing structures could occur?

That sounds risky to me, for some reason. It assumes you have high confidence in maintaining a pressurized environment in the wheel well areas, where you also assume, lies your greatest risk of damage, in the likelihood a breach could occur. JMO

We're gonna run 17,00 MPH through outer space. Maybe if you have ever stuck your hand out the window at 60+ MPH, you will notice the wind wantss to rip it off. The same effect works in space.

There is no air in outer space so there is no wind resistance. That's why things keep their orbit once in orbit, there's nothing to slow their momentum and so orbiting objects are at an equilibrium of speed and centrifugal force. If tiles were damaged on lift-off, the time this damage would've become critical would be on re-entry because re-entry is when the shuttle attains maximum speed through the atmosphere. Put your hand out the window of a shuttle doing mach 18 in it's orbit and you feel nothing. Put you hand out the window of a shuttle doing mach 18 in the earth's atmosphere and it would be ripped off.

hat leakage, pinholes, etc in the wing structures could occur?

With the tires residing in the wheel wells - and behind the wheel well doors - any debris that causes 'pinhole' damage to an exterior panel has been shown to 'pancake' (spread out after impact) and not penetrate subsequent 'layers' - such as the exterior layers of the tire ...

One would sure hope not. Space debris, micro-meteorite, foam or ice impacts on tiles or wing edges; damaged or punctured or removed allowing sustained exposure to high heat, none of them are something I would want to have to design for and be asked to sign a guarantee as to their performance.

I know these are not your standard tire you buy at O tires or Costco.

Thanks

The data from sensitive devices that record infrasound, or low-frequency sound waves inaudible by humans, was sent to NASA, said Eugene Herrin, a geophysicist at Southern Methodist University in Dallas.

As near as I can determine this Infrasound System is the system that provided the infrasound data - Infrasound Station Map .

The thing blew up over my house

I have never seen the Space Shuttle or the ISS. None of them come this far north. So, we miss the Shuttle, but we get other things that are rare down south. We get the Aurora Borealis all the time, and some say it makes a sound. Not a boom, just a hiss.

I see what you are trying to say about the wheel well, but the sensors began failing before the wheel well. It was one of the last sensors to go.

Let me preface that I have been on flight failure investigations such as this and there is a possibility NASA is not discussing. we had a failure on a different program due to overheat of electrical cables. Some were attached to sensors and it looked initially like the sensors showed a heating rise. But it was really the insulation in the cable breaking down. I.E. the temperature rise was a false reading, actual temperatures along the cable run (like in the wheel well) were much hotter, like 1500 degrees C). This can also fail other sensors, like the wheels down sensor.

Now I accept that the wheel did not deploy, if they say there was not enough drag evidence, thats another factor that is independent of the sensors and what they do or don't tell us.) But what about losing the wheel well door? or the tiles over the door. anything that could put a hot jet on the cable runs could cause various sensors in the cables to fail at various times, as was seen. And the changes will look like sensor readings because the resistance of the cable insulators will change gradually.

Finally, if they move away from the foam impact as root cause, what about sabotage of the tiles on the wing?

Tin-foilers, that's rich. The 2 lb. piece of insulation that was filmed striking the left wing during launch couldn't possibly be a cause? Meanwhile, people are floating theories about cosmic lightning and meteor collisions, and those are viable theories? You're getting mixed up on who the tin-foilers are.

If foam had corrupted the skin of the craft early in flight, sensors would have failed well before re-entry.

You should get a handle on your gross assumptions before you talk about other people being "tin-foilers". The only tin foil I see here is coming from you.

Agreed. For starters, I wonder if there's not a more durable thermal protection system that can be put in place now instead of 28,000 glued-on tiles.

I don't see a better space vehicle built in the forseeable future.

NASA is simply not able to think in a different mindset about space. For them, it will never be a business, but a place to dump taxpayer money. They also have a certain self-image to maintain that requires space to be risky and suitable only for government enterprise.

The engineers who know how to make a decent launcher don't have billions to throw at the problem, and even if they did their main customer would be a government "captured" by aerospace companies happy with the status quo. Why would Boeing ever replace a system that costs $100 million per launch with a system that costs $1 million per launch? One hundred times as much launch business isn't a sure thing.

If NACA had been operated like NASA, there would have been half a dozen transatlantic flights before the transatlantic flight program was canceled and cross country flights would be so expensive only the government could afford them.

I do not discount the fact the foam struck the wing.
I do take into account it happened very early in flight.
I recognize that it also happens on every flight, to some extent. I have never been impressed with the Space Shuttle technology and feel it is living up to its potential.
14 people have been killed on that POS.
7 going up.
7 going down.
As I said on another thread, launch the thing a hundred more times and those numbers will probably triple.(42)
Design 'mission specific' craft and costs will decrease and safety will increase.
As far as tin-foilers, I usually don't use that term, unless in reference to myself.
My apologies.

I have never been impressed with the Space Shuttle technology

It is 20 years past time to have a different man-rated launcher. I never liked the Space Shuttle: too fragile, not robust.

They can build a BDB based on the Space Shuttle minus the wings, crew compartment, ceramic foam, and landing gear. Maybe they can recover the main engines and the SRBs after every launch, or maybe it's not worth it.

For manned launches they want something more robust, not flimsy like a SSTO. So what if it has a couple of stages? The ship can be rugged. It's not against the law.

And, may I add for NormsRevenge (and others) benefit, taking the inflated tire from an environment of atmospheric pressure (about 15PSI) into deep space (about 0 PSI) will not cause it to explode or expand greatly. It changes the differential pressure from 300 PSI (as seen at the earth's surface) to 315 PSI.

Thanks for the factual details.

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