era@scdpyr.ucar.edu (Ed Arnold) (05/26/88)
Having read the McConnell book, I kind of assumed the "real" causes
of the disaster had been identified. However, I didn't read the
dissenting Feynman opinion. Anyway, the May 1988 issue of
_Defense Science_ (a miserable rag, perhaps, but don't we all
ogle the Enquirer in the supermarket? :-) ) printed an
article entitled "[New analysis indicates other causes for]
The Challenger Disaster". This claims that the real cause of the
disaster was not a leaking o-ring per se, but enormous forces
caused by the navigation system correcting sidethrust caused by
a leak that was REALLY due to assembling a round booster mid-section
with an out-of-round lower section.
Does anyone out there have any opinions about this point of view?
If you aren't familiar with this point of view, I can send you a
copy of the article if you don't have access to it ... USnail a
SASE to the address below.
--------
Ed Arnold * NCAR (Nat'l Center for Atmospheric Research) * Mesa Lab
PO Box 3000 * Boulder, CO 80307-3000 * 303-497-1253
era@ncar.ucar.edu (128.117.64.4) * {ames,gatech,noao,...}!ncar!eramears@hpindda.HP.COM (David B. Mears) (05/27/88)
I read an article some time ago (I think it was in IEEE Spectrum, but I
don't remember for sure) which talked about the speculations of one
scientist. I don't remember the name of the scientist, and the article
indicated that not many people took much stock in this person's opinions,
nevertheless, he believed that wind sheer played a big part in the
disaster. He also postulated that the wind sheer was severe enough
that the struts would have broken apart from the wind sheer even without
having been weakened by the SRM exhaust leak.
David B. Mears
Hewlett-Packard
Cupertino CA
{hplabs, ihnp4!hpfcla}!hpda!mearsjmckerna@polyslo.UUCP (John L McKernan) (05/28/88)
In article <3330004@hpindda.HP.COM> mears@hpindda.HP.COM (David B. Mears) writes: >I read an article some time ago (I think it was in IEEE Spectrum, but I >don't remember for sure) which talked about the speculations of one >scientist. I don't remember the name of the scientist, and the article >indicated that not many people took much stock in this person's opinions, >nevertheless, he believed that wind sheer played a big part in the >disaster. He also postulated that the wind sheer was severe enough >that the struts would have broken apart from the wind sheer even without >having been weakened by the SRM exhaust leak. This is second posting I've seen on the subject of the causes of the Challenger disaster. That seems a little strange to me because I thought the causes were well understood. What I understood from the media was that the seal of one of the solid rocket booster segments failed, allowing a jet of burning rocket fuel to escape at the joint. This jet of rocket fuel then ruptured the external tank causing the explosion which caused the vehicle to break up. If anyone has another explanation of what happened, and has a reference to back that explanation up, it might be interesting to hear it. Also, how complete is the consensus for that explanation? Is there a broad consensus for one explanation of the challenger accident? John L. McKernan. Student, Computer Science, Cal Poly S.L.O. -------------------------------------------------------------------------------
henry@utzoo.uucp (Henry Spencer) (05/29/88)
>... I don't remember the name of the scientist, and the article >indicated that not many people took much stock in this person's opinions, >nevertheless, he believed that wind sheer played a big part in the >disaster. He also postulated that the wind sheer was severe enough >that the struts would have broken apart from the wind sheer even without >having been weakened by the SRM exhaust leak. That will be Ali Abutaha [I think that's the right spelling]. He came up with a steady stream of unconventional theories about Challenger for a little while. Some of them were taken seriously enough to be investigated at some length, with negative or inconclusive results. Others have not been pursued. My impression is that there's a general consensus that his structural-failure theory is not numerically plausible, although NASA *is* being more cautious about high-altitude windshear these days. -- "For perfect safety... sit on a fence| Henry Spencer @ U of Toronto Zoology and watch the birds." --Wilbur Wright| {ihnp4,decvax,uunet!mnetor}!utzoo!henry
belmonte@sleepy (Matthew Belmonte) (05/31/88)
Mailed-Date: Tue, 31 May 88 11:02:21 EDT News-Relay: @wrath.cs.cornell.edu References: <247@ncar.ucar.edu> <3330004@hpindda.HP.COM> <2951@polyslo.UUCP> In article <2951@polyslo.UUCP> jmckerna@polyslo.UUCP (John L McKernan) writes: >In article <3330004@hpindda.HP.COM> mears@hpindda.HP.COM (David B. Mears) write >disaster. That seems a little strange to me because I thought the causes were >well understood. What I understood from the media was that the seal of one of >the solid rocket booster segments failed, allowing a jet of burning rocket fuel >to escape at the joint. This jet of rocket fuel then ruptured the external tank >causing the explosion which caused the vehicle to break up. It was my understanding that the jet melted through a connecting strut which fastened the SRB to the ET. The torque about the upper connecting point then caused the SRB to rotate, its nose rupturing the ET at or near the intertank portion.
dietz@awamore.cs.cornell.edu (Paul F. Dietz) (05/31/88)
The point to ponder is that we really don't know why the joint failed. Did the cold have something to do with it? Joints have suffered damage in warm weather. Perhaps increasing the leak test pressure to 200 psi? Or maybe the stretching of used booster segments? Or something else that hasn't been discovered? Since we don't know, we can't be confident the problem has been fixed. Paul F. Dietz dietz@gvax.cs.cornell.edu
arny@wayback.UUCP (Arny B. Engelson) (06/09/88)
In article <2951@polyslo.UUCP>, jmckerna@polyslo.UUCP (John L McKernan) writes: > In article <3330004@hpindda.HP.COM> mears@hpindda.HP.COM (David B. Mears) writes: > >I read an article some time ago (I think it was in IEEE Spectrum, but I > >don't remember for sure) which talked about the speculations of one > >scientist. I don't remember the name of the scientist, and the article > >indicated that not many people took much stock in this person's opinions, > >nevertheless, he believed that wind sheer played a big part in the > >disaster. He also postulated that the wind sheer was severe enough > >that the struts would have broken apart from the wind sheer even without > >having been weakened by the SRM exhaust leak. > > This is second posting I've seen on the subject of the causes of the Challenger > disaster. That seems a little strange to me because I thought the causes were > well understood. What I understood from the media was that the seal of one of > the solid rocket booster segments failed, allowing a jet of burning rocket fuel > to escape at the joint. This jet of rocket fuel then ruptured the external tank > causing the explosion which caused the vehicle to break up. > > If anyone has another explanation of what happened, and has a reference to > back that explanation up, it might be interesting to hear it. Also, how > complete is the consensus for that explanation? Is there a broad consensus > for one explanation of the challenger accident? > > John L. McKernan. Student, Computer Science, Cal Poly S.L.O. > ------------------------------------------------------------------------------- The "official" Rogers Commission reason for the Challenger disaster is certainly not the only one around. I read a very interesting article in the May 1988 issue of Defense Science by Dr. Yale Jay Lubkin (a freelance Electronic Warfare consultant, and the magazine's EW editor), entitled "The Challenger Disaster". In it, he references an article by Richard Feynman in the February 1988 issue of Physics today in which Feynman, a Nobel Laureate in Physics and a member of the Rogers Commission, details his dissenting report on the Challenger disaster. Lubkin also advises reading the extensive article by Trudy Bell and Karl Esch in the February 1987 issue of IEEE Spectrum. Also, see pictures in the March 1987 issue of the British magazine Spaceflight News. From what I gathered in Lubkin's article, the explanation supported by Feynman is based on the work of Ali AbuTaha, an experienced space engineer who has gathered an impressive amount of evidence to support his claims. Basically, he claims the leak was continuous (not intermittent as claimed by NASA and the R.C.), and that it was the attempt to correct the sidethrust which sent the Challenger into violent oscillations and caused the side of the booster to break out. The article claims Morton Thiokol goofed on the design and misused the O-ring. The internal pressure of the rocket was supposed to squash the O-ring into a good seal, but the O-ring was stronger than the rocket wall, causing the wall to deform instead of the O-ring, lifting the O-ring away from the joint, and causing the continuous leak (sidethrust), which led to attempted corrections, and the resulting disaster. The article then goes on to tell how NASA ignored AbuTaha's ideas and his evidence. If you want to know more, read the article(s). - Arny Engelson P.S. I hope I have been accurate in paraphrasing Lubkin, but suggest you read the article before commenting. Defense Science is published by Rush Franklin Publishing in Campbell, CA. (408) 370-3509
amlovell@phoenix.UUCP (06/09/88)
As I understand it, the UNTOLD story is that any number of things could
have caused the disaster because the shuttle was not being used
properly.
Many people are under the delusion that hi-tech companies and
contractors built the shuttle. Mais non! The space shuttles weren't
BUILT! They were discovered. They are naturally occurring objects,
just like rocks. Only the US flags were added, and a few in-flight
munchies whipped up in case anyone got hungry. Someone came up with the
idea that this thing looked ALMOST as though it would fly. ("Hey! look
at it from over here! Squint your eyes. Now.. don't these things look
like WINGS?") This was (as eventually became obvious) a bad idea.
It blew up because it was never meant to fly. Several people have
been puzzled about whether or not we should build a replacement for the
Challenger, but this "confusion" is a cover. The things aren't easy to
find. Not like those Saturn and Mercury things which were almost like
weeds in their numbers.
--
amlovell@phoenix.princeton.edu ...since 1963.
disclaimer:
These are MY opinions. You only WISH they were yours.eugene@pioneer.arpa (Eugene N. Miya) (06/10/88)
In article <1334@wayback.UUCP> arny@wayback.UUCP (Arny B. Engelson) writes: >resulting disaster. The article then goes on to tell how NASA ignored >AbuTaha's ideas and his evidence. > >If you want to know more, read the article(s). > > - Arny Engelson > >P.S. I hope I have been accurate in paraphrasing Lubkin, You did a good job, I checked out this article for RISKs. The only thing I would like to add is to consider the irony: we've divided the world into "NASA's ideas" and "Abu-Taha's ideas." If NASA had initially adopted "Abu-Taha's ideas," we might be hearing the name of the guy who is anonymously "NASA's ideas." [Rashomon] One more added note which I also mentioned on RISKS, checking this source out at the Ames library, I also thumbed thru "Engineering and Science" and found Feynman's Caltech obit (5 pages). Another gross generalization from --eugene miya, NASA Ames Research Center, eugene@aurora.arc.nasa.gov resident cynic at the Rock of Ages Home for Retired Hackers: "Mailers?! HA!", "If my mail does not reach you, please accept my apology." {uunet,hplabs,ncar,ihnp4,decwrl,allegra,tektronix}!ames!aurora!eugene "Send mail, avoid follow-ups. If enough, I'll summarize."
henry@utzoo.uucp (Henry Spencer) (06/14/88)
Anyone trying to assess the relative merits of NASA's explanation of 51L
and Ali AbuTaha's version should read AbuTaha's article in the May (?)
(I know it was recent but don't have the issue handy to verify the date)
issue of Spaceflight. Can you say "incoherent"? Conceivably it might
have been mangled after it left his hands, but I'd be surprised. My
opinion of him dropped quite a bit when I saw that. His ideas do deserve
a look, but don't assume that because he's the underdog, he's automatically
right.
--
"For perfect safety... sit on a fence| Henry Spencer @ U of Toronto Zoology
and watch the birds." --Wilbur Wright| {ihnp4,decvax,uunet!mnetor}!utzoo!henry