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

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

[Budge]

"Why can't we keep grabastic pieces of amphibious sh#t from falling off the rockets during launch?"

This may not be the only reason, but it may have something to do with it.

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. Foam cause damage to a ceramic tile?! That seems unlikly, however, when that foam is combined with a flight velocity between speeds of MACH two to MACH four, it becomes a projectile with incredible damage potential.

This is from an article written by Greg Katnik who is a mechanical systems engineer at the Kennedy Space Center for the group that is responsible for the shuttle's external tank, solid rocket boosters, main engine and thermal protection system.

The article was published December 23, l997

[Mat_Helm]

Looked more like a large chunk of ice than it did foam as it bounced off the tank first and split into two pieces which struck the left wing near the wheel well area. A 50 pound chunk of ice at Mach 3 would do a lot of damage to the tiles and landing gear door.

[colorado tanker]

I expect that there are certain tiles that are more critical than others - perhaps it was one of these that was hit.

One theory I heard this morning is being investigated is that the "foam" may have hit a left side wheel well cover, damaging its seal, which could have let heat into the well during re-entry. One of the first sensors to go out was at that location.

BTW, I also heard a report that the "foam" when hardened has the consistency of a brick.

[Bloody Sam Roberts]

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

Poor analogy. I realize mine isn't perfect either, but the relative velocity of the debris that struck the orbiter was a lot greater than a marshmallow being tossed inside a Concorde at cruising speed.

Just the acceleration from the insulation being caught in the passing air is enough to make it a formidable projectile.

[wretchard]

Do you have any sense of whether the foam hardens, if only briefly, when cooled by the cryogenic tank? The foam blocks appear compact before striking the underside of the left wing but is reduced to spray or powder after impact. I am just wondering how hard I need to project a piece of foam to pulverize it on impact. Also, the foam itself would not necessarily have struck the wing along its full surface area. If the fragment struck along its edge, the entire kinetic energy would have been imparted in a very small area, like an icepick. An icepick, even lightly struck can cause cracks in brittle surfaces which later propagate. Everyone who has sailed knows that the wind can capture a large amount of energy and impart it to a sail. What are the vortices like between the tank and the wing. They could well have provided the critical kinetic energy needed to crack the tiles.

[r9etb]

One theory I heard this morning is being investigated is that the "foam" may have hit a left side wheel well cover, damaging its seal, which could have let heat into the well during re-entry. One of the first sensors to go out was at that location.

I've speculated that -- is there a news or NASA source on it?

[lepton]

f you're flying on the Concorde and a flight attendant throws a marshmallow at you, you still won't be affected

The proper comparison is somewhere in between, given that the shuttle is accelerating, and the foam was likely decelerating rapidly due to wind resistance.

[colorado tanker]

is there a news or NASA source on it?

OK, I'll confess. The source is NPR, which said the issue came up in a recent NASA press conference. When asked about possible damage to the wheel well cover, the NASA guy responded to the effect that "you and I are thinking along similar lines" but he didn't want to zero in on one theory this early which might prejudice his evaluation of other evidence. I rarely listen to NPR, but their coverage of this has been pretty good.

[r9etb]

Thanks for the info. It's good to know that I'm not the only one speculating along those lines. I seem to recall a training class back when I first started working Shuttle that talked about how vulnerable those doors were to seal damage.

[colorado tanker]

I seem to recall a training class back when I first started working Shuttle that talked about how vulnerable those doors were to seal damage

I'm not an engineer, so you would know much more than me, but that was the thrust of the speculation, that if debris struck the well cover it would have hit the most vulnerable spot on the underside of the wing.

[r9etb]

The proper comparison is somewhere in between, given that the shuttle is accelerating, and the foam was likely decelerating rapidly due to wind resistance.

There's a lot of turbulent airflow between the ET and the Shuttle -- it's possible that something big -- ice or insulation -- could have been dashed directly against the tile, and not been just a glancing blow.

The blob, and the size of the "puff" after impact suggests that it was something fairly good-sized.

Judging from the comparison of the blob to the cabin door, it looks like the thing has dimensions on the order of a couple of feet.

The fact that it was pulverized suggests that there could have been a good sized impact. (Or it could simply have been pulverized by shock waves -- like I said, lotsa funny stuff goes on in that area.)

FReeper John Jamieson has posted info on testing the tiles by dropping quarters on tiles. John, do you have any insights as to what a 2-foot hunk of ice or insulation could do to, say, the main gear door?

[snopercod]

Thanks, but my computer is too old - I can't see the video.

[Lael]

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

The 'foam' is foam. But, what pulled off the foam was none other than ICE!!

The ice accumulated on the foam as the Columbia Shuttle sat there during countdown. Remember, January 1986 was just as bitterly cold as this January, with much of the South in freezing condition for several weeks.

Allusion to the thick ice was made to several reporters by a "whistleblower" and was carried about an hour after people began to speculate about the foam.

I heard it as I surfed the radio/cable news channels.

Then it was dropped!

[#3Fan]

Thought you might want to see this clip.

Sure, thanks. :^)

[John Jamieson]

Landing weight of sts107 = 232788 (from another freeper)
sts96 = 219890
sts98 = 198909

Unless there has been a heavier reentry I couldn't find, STS107 was subjected to about 6% more heat load than any other Shuttle in the history of the program. Other Shuttle flights may have far more tolerent of any tile damage than this one.

---

Yes, the video looks like a sheet of ice and frost to me. I don't think foam would pulverize like that. Ice would probably do much more damage than foam (it could also have been a combination). 16 degrees seems like a fairly steep angle of impact to me, already.

I'm curious to know the frame rate of the high speed film so the velocity could be estimated. This stuff may have come from farther up the tank, near the nose (vent valves), and therefore moving faster when it hit.

Boy, am I impressed with Dittemore, he should be the new NASA director, but they'll probably fire him instead if history is any lesson.

[r9etb]

Yes, the video looks like a sheet of ice and frost to me.

On STS-32 there was an iguana crawling up the ET just prior to launch. He either fell off once they lit the mains, or he ducked into the oxygen vent at the very top. At any rate, he wasn't there after the "twang."

We used the little fellow as a mascot for a group we had -- called ourselves the "barbequed iguanas."

I don't think this was an iguana strike, though....

[John Jamieson]

I was out on cruise boat from Port Canaveral during the launch, I come home to east Texas and the Shuttle breaks up over my home ,,,,, ironic.

Looks like the night before launch was low 40's and 100%RH, excellant for ice buildup as the foam surface temp would be below 32.

What time of day was the launch???

[glock rocks]

i've seen tornadoes push a 2X4 through a car with only 200 mph winds...

i wonder what the relative velocity of a chunk of "foam" exposed to a 2000 mph wind would be after 40 m.

one could assume a fair mass from the size of the chunk in the photo... the momentum could have been considerable.

[John Jamieson]

We should be able to calculate the speed from the film, if we had the high res film they showed today and the frame rate.

[glock rocks]

hmmm. yup.

i reckon, if we're patient, it'll all come out (and we dig enough). it may take some time... and if it doesn't... well, i might get suspicious.

thank you sir, for your level headed insight and useful information over the past couple of days.