Long-range camera footage shows foam insulation striking the shuttle's left wing during launch.

Spaceflight Now ^ | 02/03/03 | KSC ICE & Devris Team

[Fury]

Click on the multimedia clip:

http://qs240.pair.com/sfnvideo/sts107/030203e212_qt.html

It is a much better sequence of debris that appears to travel on the underside of the left wing.

[Jael]

"NASA knew from the second day of Columbia's 16-day research mission that a piece of the insulating foam on the external fuel tank had peeled off just after liftoff and struck the left wing, possibly ripping off some of the tiles that keep the ship from burning up when it re-enters Earth's atmosphere." http://www.washtimes.com/national/20030203-87326768.htm

http://ltp.arc.nasa.gov/space/team/journals/katnik/sts87-12-23.html
"Damage numbering up to forty tiles is considered normal on each mission due to ice dropping off of the external tank (ET) and plume re-circulation causing this debris to impact with the tiles. But the extent of damage at the conclusion of this mission was not "normal."

The pattern of hits did not follow aerodynamic expectations, and the number, size and severity of hits were abnormal. Three hundred and eight hits were counted during the inspection, one-hundred and thirty two (132) were greater than one inch. Some of the hits measured fifteen (15) inches long with depths measuring up to one and one-half (1 1/2) inches. Considering that the depth of the tile is two (2) inches, a 75% penetration depth had been reached. Over one hundred (100) tiles have been removed from the Columbia because they were irreparable.

During the STS-87 mission, there was a change made on the
external tank. Because of NASA's goal to use environmentally
friendly products, a new method of "foaming" the external tank
had been used for this mission and the STS-86 mission. It is
suspected that large amounts of foam separated from the external
tank and impacted the orbiter. This caused significant damage to
the protective tiles of the orbiter."



http://www.arnold.af.mil/aedc/newsreleases/1999/99-041.htm
"According to NASA, during several previous Space Shuttle flights, including the shuttle launched Nov. 29, 1998, the shuttle external tank experienced a significant loss of foam from the intertank. The material lost caused damage to the thermal protection high-temperature tiles on the lower surface of the shuttle orbiter.

Although the AEDC Tunnel A tests did not replicate the in-flight failures, they did provide detailed measurements to better understand the flight environment and fundamental failure mode. From these tests, NASA determined the failure is caused principally by foam cell expansion due to external heating at approximately Mach 4 combined with pressure change and aerodynamic shear. Specialized miniature shear gages and other instrumentation were installed during the test to measure these forces."

[Bloody Sam Roberts]

Does anybody know what this "insulating foam" is made of? I have ben wondering how hard this material might be.

Largely, it doesn't matter. Just about anything travelling at supersonic speeds will cause damage. And Columbia was supersonic at that stage of liftoff.

Example: If I throw a marshmallow at you, you wouldn't be affected. However, if i was able to hurl it at you at the velocity of 700 mph. it would likely kill you.

[Fury]

Jael, how fast was Columbia traevling when the debris broke loose?

[Budge]

I'm not Jael, but it would have been between MACH 2 and MACH 4.

[OldFriend]

Heard an engineer state that the foam hardens when it is applied.

[Fury]

As Bloody Sam Roberts commented on, anything traveling that fast is bound to do some damage.

[The Great Satan]

Just about anything travelling at supersonic speeds will cause damage.

The relative speed is what counts. That would be quite low in this instance.

[Fury]

The relative speed is what counts. That would be quite low in this instance.

Good point. I wonder how fast the debris was indeed traveling?

[The Great Satan]

Example: If I throw a marshmallow at you, you wouldn't be affected. However, if i was able to hurl it at you at the velocity of 700 mph. it would likely kill you.

If you're flying on the Concorde and a flight attendant throws a marshmallow at you, you still won't be affected. It's called Galilean Relativity.

[Budge]

Absolutely!

I meant to underline the line in post #18.

A thermal analysis was performed to determine the implications of such damage assuming various levels of damage, including multiple tiles missing over an area measuring roughly 7 by 30 inches.

[Hatteras]

"Largely, it doesn't matter. Just about anything travelling at supersonic speeds will cause damage."

Coupled with that, I understand that the material was also possibly frozen. But my question would have to be whether NASA and KSC routinely gathers debris left behind after lift off and if so (as I would imagine), how many tiles, if any, were recovered at the launch site?

[Prince Caspian]

It seems like an important question (not asked yet as far as I can tell) would be, "Why can't we keep grabastic pieces of amphibious sh#t from falling off the rockets during launch?"

[Budge]

The relative speed is what counts. That would be quite low in this instance.

Not according to NASA reports. Debris hitting the wing at MACH 2 to MACH 4 would cause considerable damage.

Those heat shield tiles are basically nothing more than foam with a very thin protective coating on them.

One can actually be damaged simply by dropping a quarter on it from only two feet.

[ContemptofCourt]

That's why this is rocket science.....

From a serious point, the external fuel tank shrinks up to 6 inches when filled....I imagine that plays havoc with the foam insullation

[stayout]

Did anyone else notice something I noticed when replaying the clip over and over? The attitude of Columbia distinctly jumps to the right in the frame right after impact (the frame where a spray of disintegrated material appears below the left wing).

If I am right, then the force applied to Columbia by the foam impact must have been significant to shove Columbia over even a couple of feet from its previous trajectory.

[Jael]

I am not sure. Mach 4 rings a bell, but that could be in reference to another lift off in which foam hit the Columbia.

[The Great Satan]

I wonder how fast the debris was indeed traveling?

The relevant equation is:

v squared = 2 * a * d

The acceleration due to gravity is approximately 10 meters per second per second. The shuttle is a couple of hundred feet tall, or thereabouts. Let's put d as 45 meters to make the arithmetic easy. Then we have:

v squared = 2 * 10 m/s/s * 45 m = 900 m squared / s squared

Which would give us an impact velocity of 30 m/s, which is about 70 mph by my reckoning.

[The Great Satan]

Differential air resistance and the acceleration of the shuttle itself would increase the impact velocity that I calculate above, although we are still not talking remotely of supersonic speeds.

[jlogajan]

What about aerodynamic braking??? I think the speed differential would be more than 70mph at impact.

[jlogajan]

Never mind. :-)