Since Doug Jones uttered the name Henry Spencer in a recent comment, I decided to ring Henry and compare notes. A very interesting 15 minutes pooling our various bits of hearsay and rumour…
Henry thinks a heat induced tireburst in the wing is one possible scenario. As we know (think Concorde) such events can be extremely violent and cause air frame damage.
For my part, I note the best place to run the hydraulic loops from the APU’s is right through a section of rear fuselage and wing root where the news have been pointing to as places where the temperature rises were seen shortly before loss of communication. Neither of us knows exactly how the hydraulic lines run and how far apart their independant paths are. However the lines all have to come together at the actuators for the ailerons (or elevons since they can provide both functions I believe).
Loss of the hydraulic loops would cause instant and violent loss of control, but I would expect at least a small amount of data showing the lines popping before the control loss occurs. I am not privy to any such data.
Henry’s suggestion on the tire gives us a very sudden air frame damaging event, but unless it causes immediate catastrophic structural failure, I can’t see it happening without the crew knowing a few seconds in advance something was terribly wrong.
I would expect clear signatures of either in telemetry. I guess we all have to say “we don’t know”, and we are at a disadvantage without access to the actual telemetry and time sequence.
Which is of course what teams of engineers at NASA are most likely doing right now.
Also, Henry reports from his sources that there is uncertainty that remains of all 7 have been found yet. They announced one way and then back tracked apparently.
No one has found the significant heavy structures of the shuttle: the SSME’s or major portions of the crew pressure vessel. Something the size of a compact car is said to have gone down into a reservoir but it has not been found and no one knows what it was. The fact that remains have been found tells us the pressure vessel must have been split open.
It is likely these items travelled the farthest. They could be deep into Louisiana or perhaps into the Gulf of Mexico. If the latter, there is the risk they will not be found for a very long time.
Hopefully Henry will drop by and add his tuppence (Canadian) to these random jotting about our brief brainstorm.
MORE: A 6-7ft long piece of the cabin has been found. Added to the evidence that astronaut remains have been found, I think it is safe to say the pressure vessel and contents were shredded pretty thoroughly. The good news is, more of it is likely to be found around Nacogdoches rather than further down range. There is still no word of the three SSME’s.
STILL MORE The Indendant claims bits will still be turning up in ten years. Ten years hell: centuries more like. Not to mention the few odd bits that will make it into fossil layers to be dug up a hundred million years hence. We are talking about hundreds of thousands of shuttle bits spread over half of East Texas and potentially spread from California to Louisiana and the Gulf of Mexico. They’ll be lucky to even find all the big parts this side of 2100!
AND MORE They have now found the nosecone
I have one more theory to throw into the pot. I have no idea if there is any evidence for it, but maybe some aerodynamic type folks will comment.
Assume that some tiles fell off, enough to create some significant aerodynamic drag under the left wing. There could be significant assymetrical drag that needed to be counteracted by the control surfaces. Maybe the control surfaces did not have enough authority to overcome the drag differences and the craft spun out.
The loss of the tiles probably had some effect: there was a larger degree of correction in the autopilot that in previous flights. However, that alone is not enough to put the vehicle out of control. It’s a very big ship.
Now if Henry were right, and the tire blew out the wheel well doors… now we have a nasty situation…
You have to consider the tiles are a covering over the airfoil, so losing doesn’t necessarily change the lift by much. It does change the airflow; it does, as you say, add a bit of drag.
LGF has a pic of the wing when Sharon was speaking to Ramon.
I’ve been busted by Instapundit. Pic is false.
Your mention of the Concorde disaster rang a bell with me. Since the evidence of possible causes has been emerging, there has been a sense of deja vu harking back to the Charles de Gaulle “debris damage” that led to the catastrophic loss of the aircraft.
Nasa keeps insisting its evaluation on the ground led it to conclude the tile and wing damage did not constitute a re-entry danger, and if this is vindicated (it seems to be based on the outcome of previous such incidents) then the possibility of damage allowing heat build-up in the wheel bay has to be a strong possibility. If I’m not mistaken, the flying insulation seemed to strike first the leading edge of the left wing and then the underside of the shuttle.
I’m just a lay space buff, and stand ready to be severely corrected …
Sandy: Yep. I heard about the photo and was rather skeptical as the angle looked more like an external shot. Payload bay, ISS, I don’t know. It just seemed “wrong”. And in fact, the news show I was watching corrected it before the end of the hour!
Dave: You are not going to be severely corrected. Only minorly corrected. The scenario Henry is looking at would depend on the wheel well thermal gasket being breached and the hot gasses leaking in. Close enough to what you are thinking as to not make much difference.
I’m not convinced 100% on that scenario, or for that matter the tile damage one, although I’m about “80% confident” that is the root cause. As to the secondary cause, it could be the tire, it could be the spar, it could be the hydraulics…
My first thought was a tire explosion when I heard the info about tire pressures.
If the explosion caused a hydraulic failure as well, the combination of damage from the tire and violent change in ailerons could have provided g forces so severe that no crew reaction was possible. A snap roll type of thing, followed within a second or two by breakup.
I’m buying the no tile damage theory for now, though I expect that it will be blamed. For no other reason than no attempt was made to visualize the area. They should have looked.
According to Dittemore, they did not attempt to look because nothing they could look with, would have provided sufficient clarity to determine what the damage, if any, actually was. But to a followup, he basically admitted that even if they had looked and had known, there was nothing they could do….
As for my own (Canadian) two cents, I suspect a tile loss along the leading edge, maybe outboard of the wheel well line. It allows, in effect, a blow torch of gas into the wing interior, and growing damage, without significant drag change at first. Note that a worker for Xcorp, in the Mojave saw what he thought was something separating from the craft, about 15 minutes before loss of contact..He was using binoculars and he guesstimated the range at 220 miles (report posted in letters at Jerrypournelle.com).
The heating in the wing would account for the 60 degree/5minute report, and eventually for the increased tire pressure. The hydraulic pressure reading drop was/is the signal for catastrophic failure, as the control system was compromised and a snap-roll/spin would follow….
“Pioneering is the business of learning new and unexpected ways of dying”.
Farewell brave pioneers.
Geoff
Hmmmm…. Silly question… If the chunk of insulation (and mebbe ice) knocked off tiles on launch, has *anyone* looked for tile debris near the *launch site* yet? If they find some tiles, it might tell them a bit about how much, and where the damage occured.