mcdowell@cfa250.harvard.edu (Jonathan McDowell) (09/29/88)
HOORAY! Discovery's in orbit at last. Phew. BUT.... At about 80 to 90 seconds into the flight, I and several friends independently thought we saw flame coming out of the right hand (no, right on the TV screen, so I guess that must mean its really the "left hand") SRB at the case-to-nozzle joint (where the cylindrical booster starts to flare toward the bottom). Did anyone else see this? The commentators didnt mention it. I hope I'm wrong. Jonathan McDowell
elturner@phoenix.Princeton.EDU (Edwin L Turner) (09/30/88)
>HOORAY! Discovery's in orbit at last. Phew. > >BUT.... At about 80 to 90 seconds into the flight, I and several >friends independently thought we saw flame coming out of the right hand >(no, right on the TV screen, so I guess that must mean its really the >"left hand") SRB at the case-to-nozzle joint (where the cylindrical >booster starts to flare toward the bottom). Did anyone else see this? >The commentators didnt mention it. I hope I'm wrong. > > >Jonathan McDowell I greatly fear that you are not wrong. I and at least two other friends all watching it separately here in Princeton noticed the same thing. I taped the launch and have rewatched it and have compared it to a tape of the Challenger accident. The apparent flame plume in this morning's launch looked fairly similar to the O-ring burn through in the Challenger launch. I would modify the description you give above only in that the position of the plume seemed somewhat less stable; it appeared to move around considerably and flicker in brightness. It may well be that we are all misinterpreting what we saw. Perhaps it was some minor and/or entirely normal event. All may be well, but I think that there is at least a moderate probability that, after looking at the many available camera angles and inspecting the recovered SRB's, NASA will announce that this morning's launch only narrowly escaped disaster. If there was another O-ring burn through, it will surely AT LEAST mean another major delay in the shuttle program. Ed Turner "Does one really have to fret phoenix!elturner About enlightenment? No matter what road I travel, I'm going home." or elturner@phoenix.Princeton.EDU
DOHC@TUCCVM.BITNET (Bob Roberds) (09/30/88)
>HOORAY! Discovery's in orbit at last. Phew. > >BUT.... At about 80 to 90 seconds into the flight, I and several >friends independently thought we saw flame coming out of the right hand >(no, right on the TV screen, so I guess that must mean its really the >"left hand") SRB at the case-to-nozzle joint (where the cylindrical >booster starts to flare toward the bottom). Did anyone else see this? >The commentators didnt mention it. I hope I'm wrong. I thought I saw that too. And NBC (I think it was) mentioned it. NASA guys sed "don't sweat it." I for one will stop sweating it after the SRBs have been examined REAL closely.
chguest@pioneer.arc.nasa.gov.arpa (Charles Guest RCE) (09/30/88)
In article <1104@cfa237.cfa250.harvard.edu> mcdowell@cfa250.harvard.edu (Jonathan McDowell) writes: > >HOORAY! Discovery's in orbit at last. Phew. > >BUT.... At about 80 to 90 seconds into the flight, I and several >friends independently thought we saw flame coming out of the right hand >(no, right on the TV screen, so I guess that must mean its really the >"left hand") SRB at the case-to-nozzle joint (where the cylindrical >booster starts to flare toward the bottom). Did anyone else see this? >The commentators didnt mention it. I hope I'm wrong. > > >Jonathan McDowell Unless it was a nationwide hallucination you did in fact see what you think you saw. I noticedit too. I was listening to a prss confrence on NASA select at about 1400 pdt this afternoon and a member of the press asked this exact question. The moderator poo pooed the ideaand said that he hd not seen it. It may be tat the government wanted to present~this as a flawless flight so they will wait until they are certain what exactle happened before they release any data. ps. the H key on my terminal is not working properly...please forgive the typos. ************************************************************ * OVERAL AND ALL INCLUSIVE DISCLAIMER: * * (except for what I left out and meant to say) * * The above reply/article is my opinion **only* * * True and articulable facts had no bearing on * * the above statements. 8=) :-) :-> * ************************************************************
DOHC@TUCCVM.BITNET (Bob Roberds) (09/30/88)
>It may well be that we are all misinterpreting what we saw. Perhaps it was >some minor and/or entirely normal event. All may be well, but I think that >there is at least a moderate probability that, after looking at the many >available camera angles and inspecting the recovered SRB's, NASA will >announce that this morning's launch only narrowly escaped disaster. >If there was another O-ring burn through, it will surely AT LEAST mean >another major delay in the shuttle program. Tonite on the news I heard that NASA had found no evidence of a burn-through fire on the recovered SRBs. Let us frigging hope they're right. Geez, how could you have burn-through with the new flange and three-ring system? If it happened, we can all look foward to another two and a half years of frustration and (hopefully) the death sentence for the managers at Morton Thiokol.
cs293ad@unm-la.UUCP (Hugh Hazelrigg) (09/30/88)
In article <3811@phoenix.Princeton.EDU> elturner@phoenix.Princeton.EDU (Edwin L Turner) writes: > >>HOORAY! Discovery's in orbit at last. Phew. >> >>BUT.... At about 80 to 90 seconds into the flight, I and several >>friends independently thought we saw flame coming out of the right hand >>(no, right on the TV screen, so I guess that must mean its really the >>"left hand") SRB at the case-to-nozzle joint (where the cylindrical >>booster starts to flare toward the bottom). Did anyone else see this? >>The commentators didnt mention it. I hope I'm wrong. >> >> >>Jonathan McDowell > >I greatly fear that you are not wrong. I and at least two other >friends all watching it separately here in Princeton noticed the same thing. I saw it too. In spite of the news media's description of the event as "picture perfect", the picture I saw was heart-stopping. After watching the replays of the ill-fated last mission so many times that I became inured to the horrible reality of the loss of life and the setback to the program, I became sensitized to the implications of the telephoto image broadcast to our TV screens. I am sure that I saw something that looked very much like the flame plume which is blamed for the Challenger's demise. I shall not be surprised when NASA announces another major delay in the program. hugh
tbetz@dasys1.UUCP (Tom Betz) (09/30/88)
Quoth mcdowell@cfa250.harvard.edu (Jonathan McDowell) in <1104@cfa237.cfa250.harvard.edu>: | |HOORAY! Discovery's in orbit at last. Phew. | |BUT.... At about 80 to 90 seconds into the flight, I and several |friends independently thought we saw flame coming out of the right hand |(no, right on the TV screen, so I guess that must mean its really the |"left hand") SRB at the case-to-nozzle joint (where the cylindrical |booster starts to flare toward the bottom). Did anyone else see this? |The commentators didnt mention it. I hope I'm wrong. | | |Jonathan McDowell Yup, I saw it too. It's the ghost of Nixon's Congress coming back to haunt us. "That reuseable liquid-fueled air-launcher is too expensive... why don't you just use solid-fueled rockets? Hell, it's good enough for our ICBMs... it should be good enough for NASA!" So long as we keep using this bargain-basement design, we're going to have the same risk, no matter how much NASA tries to gloss over it. And the worst thing about is that it's Nixon's fault. -- "If I found the truth I would tell you and you |Tom Betz would have me shot." -- Carlos Fuentes -- |ZCNY, Yonkers, NY 10701-2509 Those who purchase a little safety at the price of |UUCP: tbetz@dasys1.UUCP or liberty will soon have neither liberty nor safety. | ...!cmcl2!phri!dasys1!tbetz
jonkatz@ga.ecn.purdue.edu (Jonathan W. Katz) (09/30/88)
In article <3811@phoenix.Princeton.EDU> elturner@phoenix.Princeton.EDU (Edwin L Turner) writes: > >HOORAY! Discovery's in orbit at last. Phew. > >BUT.... At about 80 to 90 seconds into the flight, I and several >friends independently thought we saw flame coming out of the right hand >(no, right on the TV screen, so I guess that must mean its really the >"left hand") SRB at the case-to-nozzle joint (where the cylindrical >booster starts to flare toward the bottom). Did anyone else see this? >The commentators didnt mention it. I hope I'm wrong. > > >Jonathan McDowell > I think that I must agree. I'm not exactly sure about the time (I believe it was about 10 seconds MET; I'll have to review the tapes) I noted an abnormal plume of smoke coming from the right hand SRB. This smoke only lasted a few seconds but after Challenger, a few seconds can mean a lot. Jonthan W. Katz Purdue University School of Aeronautical and Astronautical Engineering
beres@cadnetix.COM (Tim Beres) (09/30/88)
Jonathan McDowell writes: >BUT.... At about 80 to 90 seconds into the flight, I and several >friends independently thought we saw flame coming out of the right hand >(no, right on the TV screen, so I guess that must mean its really the >"left hand") SRB at the case-to-nozzle joint (where the cylindrical >booster starts to flare toward the bottom). Did anyone else see this? >The commentators didnt mention it. I hope I'm wrong. > I saw the same thing. Pretty scary, but it turns out it was just a trick of physics. The Rocky Mtn. News today devoted a couple of paragraphs to this "sighting". I'll paraphrase (so as not to upset Eugene by using info without permission :-). This question was asked of Royce Mitchell of Marshall, he said it was due to a physics principle called reverse flow seperation. As the orbiter rolls, the SRB's exhausts get mixed together creating a collision of hot particles. These collisions give the effect of the plume riding up the side of the SRB. I really wish that didn't happen though! Still seems like the outside casing of the SRB would get very hot, possibly causing other nasty effects. Anybody know more of this reverse flow seperation thingy? Tim ..words to memorize words hypnotize words make my mouth exercise words all fail the magic prize... -- VF Tim Beres Cadnetix, 5775 Flatirons Pkwy, Boulder, CO 80301 beres@cadnetix.com {uunet,boulder,nbires}!cadnetix!beres
phil@titan.rice.edu (William LeFebvre) (09/30/88)
In article <3811@phoenix.Princeton.EDU> elturner@phoenix.Princeton.EDU (Edwin L Turner) writes: >>BUT.... At about 80 to 90 seconds into the flight, I and several >>friends independently thought we saw flame coming out of the right hand >>(no, right on the TV screen, so I guess that must mean its really the >>"left hand") SRB at the case-to-nozzle joint (where the cylindrical >>booster starts to flare toward the bottom). Did anyone else see this? It seems that many people saw it. >It may well be that we are all misinterpreting what we saw. Perhaps it was >some minor and/or entirely normal event. I have it from a very reliable source that the plume was not unusual or indicative of near disaster. It is apparently a normal occurence in the very high reaches of the atmosphere (near-vacuum). I was also worried when I saw it, but someone who has an intimate knowledge about these things has (indirectly) told me that it is not an uncommon phenomenon. But I don't know what causes it. I don't think it is an optical illusion. I think it has something to do with the lack of oxygen. William LeFebvre Department of Computer Science Rice University <phil@Rice.edu>
root@mjbtn.MFEE.TN.US (Mark J. Bailey) (09/30/88)
Well, if there was some sort of O-ring burn thru, at least they will have
a better chance of examining the booster somewhat in tact to get a better
idea of what was happening. Peter Jennings on ABC mentioned the existence
of the plume and they focusses in on it briefly in a replay. He went on
to say that engineers examined it and decided that there was no immediate
danger, but that is the media talking. I would be some of the engineers
caught it and were a little anxious to get those boosters off Discovery's
sides.
I myself noticed it on the real-time liftoff but just figured that it was
just debris blow rampid as it left the booster nozzle.
Any NASA people online to comment?
Mark.
--
Mark J. Bailey "Y'all com bak naw, ya hear!"
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DOMAIN: root@mjbtn.MFEE.US.TN | Murfreesboro, TN USAknudsen@ihlpl.ATT.COM (Knudsen) (09/30/88)
Yes, I saw those extra flames licking around as soon as they switched camera angles after throttle up (and right where you-know-what blew up). I was very tense watching that. These flames were mentioned on last nite's news, and one of the morning papers said lots of knowledgeable people called NASA about it. But official word is that these flames are just some normal rocket exhaust caught in the vortex caused by "reverse flow separation." I guess the assumption is that having these reverse eddies of hot gases around the bottom of the ET is not going to hurt anything. Too bad we can't recover the ET and look at its surface. I wonder. Anyway, you can bet the joints on the SRBs will be looked at really closely when they're back on land. They would have been in any case, I suspect.
dave@viper.Lynx.MN.Org (David Messer) (10/01/88)
In article <15722@ames.arc.nasa.gov> chguest@pioneer.arc.nasa.gov.UUCP (Charles Guest RCE) writes: >In article <1104@cfa237.cfa250.harvard.edu> mcdowell@cfa250.harvard.edu (Jonathan McDowell) writes: >>BUT.... At about 80 to 90 seconds into the flight, I and several >>friends independently thought we saw flame coming out of the right hand >>(no, right on the TV screen, so I guess that must mean its really the >>"left hand") SRB at the case-to-nozzle joint (where the cylindrical >>booster starts to flare toward the bottom). Did anyone else see this? >>The commentators didnt mention it. I hope I'm wrong. > >Unless it was a nationwide hallucination you did in fact see what you >think you saw. I noticedit too. > >I was listening to a prss confrence on NASA select at about 1400 pdt >this afternoon and a member of the press asked this exact question. >The moderator poo pooed the ideaand said that he hd not seen it. > >It may be tat the government wanted to present~this as a flawless flight >so they will wait until they are certain what exactle happened before >they release any data. I noticed it also. It was probably a reflection or aerodynamic heating, but another burn-through was certainly a possibility. It angers me that the NASA officials are back to their old habit of assuring the press that everything is flawless however. They could've said that they were studying the tapes and would give a report on the cause. Instead, as you say, they poo-pooed the idea of anything being wrong. This attitude is one of the reasons for the 51L disaster in the first place. -- If you can't convince | David Messer - (dave@Lynx.MN.Org) them, confuse them. | Lynx Data Systems -- Harry S Truman | | amdahl --!bungia!viper!dave | hpda / Copyright 1988 David Messer -- All Rights Reserved This work may be freely copied. Any restrictions on redistribution of this work are prohibited.
bro@titan.rice.edu (Douglas Monk) (10/01/88)
In article <1935@kalliope.rice.edu> phil@Rice.edu (William LeFebvre) writes: >In article <3811@phoenix.Princeton.EDU> elturner@phoenix.Princeton.EDU (Edwin L Turner) writes: >>>BUT.... At about 80 to 90 seconds into the flight, I and several >>>friends independently thought we saw flame coming out of the right hand >>>(no, right on the TV screen, so I guess that must mean its really the >>>"left hand") SRB at the case-to-nozzle joint (where the cylindrical >>>booster starts to flare toward the bottom). Did anyone else see this? > >It seems that many people saw it. >>... >I have it from a very reliable source that the plume was not unusual or >indicative of near disaster. It is apparently a normal occurence in >the very high reaches of the atmosphere (near-vacuum). ... I too saw the mentioned apparition around the SRB, and was worried about it. What I saw seemed more between the SRB and beneath the external tank than to the side, though I think I saw a flicker or two there, also. It certainly looked orange to me BUT: I have seen similar flares before in launches. In a commentary program on the Challenger that I saw on television about two years ago they ran replays of other launches from several angles, and in several instances there are moments when the shock waves coming off the boosters make visible flares - but WHITE ones that appear to be contrail effects very similar to the contrail vortices we see coming off the shuttle wings as it approaches landing - in other words, made of water vapor or ice. In the same program they mentioned in passing that the SRB exhaust is so hot that it can make the bottom of the external tank glow with heat during flight, but that this is normal and expected, and that the vortex of turbulence that is immediately behind the external tank actually may dissipate some of the heat. It thus seems to me that what we saw may indeed have been "an optical illusion" in the sense that we saw a normal shock wave contrail, perhaps combined with external tank turbulence, reflecting the orange glow of the SRB exhaust. (For those interested in a more exact attribution of this program, it was during of immediately after the Rogers commission, it explained the O-rings in great detail, and it examined the history of O-ring failures in detail. However, it was quite some time ago, and I cannot be more specific. Does anyone else remember this program and give a more exact attribution?) Thanks, Douglas Monk (bro@rice.edu) Dept. of Computer Science Rice University
ruslan@ecsvax.uncecs.edu (Robin C. LaPasha) (10/01/88)
In article <15722@ames.arc.nasa.gov>, chguest@pioneer.arc.nasa.gov.arpa (Charles Guest RCE) writes: > In article <1104@cfa237.cfa250.harvard.edu> mcdowell@cfa250.harvard.edu (Jonathan McDowell) writes: > > > >HOORAY! Discovery's in orbit at last. Phew. > > > >BUT.... At about 80 to 90 seconds into the flight, I and several > >friends independently thought we saw flame coming out of the right hand > >(no, right on the TV screen, so I guess that must mean its really the > >"left hand") SRB at the case-to-nozzle joint (where the cylindrical > >booster starts to flare toward the bottom). Did anyone else see this? > >The commentators didnt mention it. I hope I'm wrong. > > > > > >Jonathan McDowell > > Unless it was a nationwide hallucination you did in fact see what you > think you saw. I noticedit too. > > I was listening to a prss confrence on NASA select at about 1400 pdt > this afternoon and a member of the press asked this exact question. > The moderator poo pooed the ideaand said that he hd not seen it. > It may be that the government wanted to present this as a flawless flight > so they will wait until they are certain what exactle happened before > they release any data. > > > ************************************************************ > * OVERAL AND ALL INCLUSIVE DISCLAIMER: * [etc., of Charles Guest] I also saw that NASA Select press conference. The question was phrased rather specifically, in fact - not a "did you see any flame out of the SRBs" but something like: I was at XXX space center with a group of technicians and managers, including at least one astronaut...I saw them literally gasp when they saw that flame licking out the side... And they moaned... What's up? [rough equivalent, from memory] The moderator/spokesman guy did "poo poo" the idea, and didn't seem to be terribly informative on some other questions by the group either. The following by Bob Roberds and (somebody else!) is also disconcerting: >It may well be that we are all misinterpreting what we saw. Perhaps it was >some minor and/or entirely normal event. All may be well, but I think that >there is at least a moderate probability that, after looking at the many >available camera angles and inspecting the recovered SRB's, NASA will >announce that this morning's launch only narrowly escaped disaster. >If there was another O-ring burn through, it will surely AT LEAST mean >another major delay in the shuttle program. Tonite on the news I heard that NASA had found no evidence of a burn-through fire on the recovered SRBs. Let us frigging hope they're right. Geez, how could you have burn-through with the new flange and three-ring system? If it happened, we can all look foward to another two and a half years of frustration and (hopefully) the death sentence for the managers at Morton Thiokol. [end of quote] It seems that NASA was _very_ quick about that check. Does anybody (watching NASA Select more faithfully than I have been) know if this is being followed up in subsequent news conferences? Like, is there any real information being presented? If it's normal, have they analyzed where it's coming from, etc.? Anybody doing checks against old shuttle tapes to see if it's a spurt of flame in the same place(s)? Robin LaPasha ruslan@ecsvax.uncecs.edu
cme@cloud9.UUCP (Carl Ellison) (10/02/88)
In article <4305@cadnetix.COM>, beres@cadnetix.COM (Tim Beres) writes: > ... As the orbiter rolls, the SRB's exhausts get mixed together > creating a collision of hot particles. These collisions give the effect > of the plume riding up the side of the SRB. There are two separate things being observed and discussed here. A smoke plum right after launch, during the initial roll, seems to be what's being discussed here. I didn't see this, but I wasn't looking for it either. The flame I saw was from a very long distance telephoto shot, just before SRB separation. I sure wish NASA would present a full explanation for both of these so we could stop speculating via USENET and get back to watching TV. --Carl
sewilco@datapg.MN.ORG (Scot E. Wilcoxon) (10/02/88)
In article <4305@cadnetix.COM> beres@cadnetix.COM (Tim Beres) writes: >info without permission :-). This question was asked of Royce Mitchell >of Marshall, he said it was due to a physics principle called reverse flow >seperation. As the orbiter rolls, the SRB's exhausts get mixed together >creating a collision of hot particles. These collisions give the effect Oh, I think I get it. Where the plumes meet, some of the flow can be forced upward (particularly at in thin atmosphere where there is less resistance?). SRB SRB ! ! ! ! ! ! ! ! ! ! ! ! /\ /\ /||\ /||\ /||||\ ^ /||||\ /||||||\ /^\ /||||||\ /||||||||\ /^^^\ /||||||||\ /||||||||||\/^^^^^\/||||||||||\ /||||||||||||\^^^^^/||||||||||||\ /||||||||||||||\^^^/||||||||||||||\ /||||||||||||||||\^/||||||||||||||||\ /|||||||||||||||||||||||||||||||||||||\ /|||||||||||||||||||||||||||||||||||||||\ -- Scot E. Wilcoxon sewilco@DataPg.MN.ORG {amdahl|hpda}!bungia!datapg!sewilco Data Progress UNIX masts & rigging +1 612-825-2607 uunet!datapg!sewilco "When Hurricane Gilbert comes through, I'll stay here to experience it." CBS:"What if you experience death?" "Well, I'll worry about that later."
peter@sugar.uu.net (Peter da Silva) (10/02/88)
In article <1104@cfa237.cfa250.harvard.edu>, mcdowell@cfa250.harvard.edu (Jonathan McDowell) writes: > BUT.... At about 80 to 90 seconds into the flight, I and several > friends independently thought we saw flame coming out of the right hand > SRB at the case-to-nozzle joint. Did anyone else see this? I remember seeing what looked like a flame where no flame should be, but I wouldn't say where the flame came from. Given that it was inside the hypersonic shock cone, it could have come from anywhere. The airflow around the shuttle must be a nightmare, what with all those discrete parts. -- Peter da Silva `-_-' peter@sugar.uu.net Have you hugged U your wolf today?
phil@titan.rice.edu (William LeFebvre) (10/02/88)
In article <1925@cloud9.UUCP> cme@cloud9.UUCP (Carl Ellison) writes: >I sure wish NASA would present a full explanation for both of these >so we could stop speculating via USENET and get back to watching TV. I sure wish you Usenet readers would exercise a little patience and give NASA a break! I just don't believe some of what I have read here the past few days. Everything from "back to their same old tricks" to rumors of a conspiracy initiated by the President's office. Come ON! Had it ever occurred to anyone out there that it might just possibly be true that NASA doesn't KNOW the answer? Had it ever occurred to anyone out there that they don't want to present the public with nothing more than speculation and half-guesses? Why don't you give them some time to (a) evaluate the film clips (possibly comparing them to previous flights) and (b) scrutinize the SRBs? I would much rather wait for NASA to give me a well researched, provable and correct answer than a half-baked hard-pressed the-public-has-a-right-to-know-yesterday answer. The launch was only Thursday, folks. Cut 'em some slack. The real people (the engineers and technicians) want to see the space program succeed just as much as you and I. They are just as interested (if not more so) in how well the SRBs performed as we are. After all, some of them have a close comraderie with the astronauts. Those people sitting at the top of that giant firecracker are *friends*. They don't want to lose them either. The press asked about the plume as early as the post-launch briefing. OF COURSE no one is going to have an answer. The SRBs have just barely splashed down! Look at the spot they were put in: if they immediately answer "oh, that's a common phenomenon---we see it all the time" and then find out that there really was a problem with an SRB, they are going to look very bad. And the public (especially the Usenetters) will accuse them of attempting to cover up a known problem. If they answer "that could be a serious problem" the press will jump all over it, mnake it sound far more serious than it is and public opinion of the revamped space program will go down the tubes along with the last remnants of faith and hope that any american still had for the manned space program. If they answer "we don't know yet---we need to study the problem" everyone screams at them for trying to hide information from the public. Like I said before: give NASA a break! And once they do decide to make a statement about this, you had better watch the entire press conference via NASA Select. Because I'm sure that the uneducated media will twist and turn the words to make it sound very much unlike what was really said. I have already experienced so many misrepresentations of the truth by the media in the past 4 days to shatter any faith I ever had in the press. But that's for another message.... William LeFebvre Department of Computer Science Rice University <phil@Rice.edu>
henry@utzoo.uucp (Henry Spencer) (10/03/88)
In article <1903@datapg.MN.ORG> sewilco@datapg.MN.ORG (Scot E Wilcoxon) writes: >Oh, I think I get it. Where the plumes meet, some of the flow can be >forced upward (particularly at in thin atmosphere where there is less >resistance?). In thin atmosphere, in fact, the plume from even a single engine will completely envelop the rocket. I'm not sure this entirely accounts for the recent reports, though, although it is pretty clear now that there were no problems with the SRBs themselves. -- The meek can have the Earth; | Henry Spencer at U of Toronto Zoology the rest of us have other plans.|uunet!attcan!utzoo!henry henry@zoo.toronto.edu
alastair@geovision.uucp (Alastair Mayer) (10/04/88)
> [several comments about the apparent 'flame' coming off the side of > the SRB during the Discovery launch] Yeah, I saw it too. But if you recall (or go back and watch if you taped it), that flame is at the *base* of the external tank (not partway up the side as in 51-L). Now, do any of you recall seeing the photos taken during STS-1 or STS-2 of the external tank after separation? The charring (easy to see against the white paint of the tank) around the base of the ET is very clear. This charring is caused (I beleive) by radiant heat from the SRB exhaust plumes - and is one of the reasons the ET is insulated. While the 'flames' at the base of the ET were unsettling, I put them down to smoke & gases coming off the ET insulation as it charred, and illuminated by the SRB exhaust plumes. Given the blunt aft end of the ET, and the 'pocket' formed there by the Orbiter body and SRBs, you'd expect gases to tend to stagnate there a bit rather than being instantly dispersed in the slipstream. All of which makes me a bit skeptical about some proposed designs for 'aft cargo carriers' to be attached at the base of the ET.
henry@utzoo.uucp (Henry Spencer) (10/06/88)
In article <417@geovision.UUCP> alastair@geovision.UUCP (Alastair Mayer) writes: >All of which makes me a bit skeptical about some proposed designs >for 'aft cargo carriers' to be attached at the base of the ET. Why? Almost any aft cargo carrier is going to be less heat-sensitive than the liquid hydrogen that's inside that part of the tank now. -- The meek can have the Earth; | Henry Spencer at U of Toronto Zoology the rest of us have other plans.|uunet!attcan!utzoo!henry henry@zoo.toronto.edu
wes@obie.UUCP (Barnacle Wes) (10/07/88)
In article <1925@cloud9.UUCP>, cme@cloud9.UUCP (Carl Ellison) writes: > The flame I saw was from a very long distance telephoto shot, just > before SRB separation. One possible explanation for this phenomenon: This is one of the more annoying "features" of large sold-fuel rocket motors, especially those in which the fuel core has been "star-cut" to provide more thrust. The problem is that towards the end of the burn, there are "sheets" of propellant that burn through and get thrown out the cone before being completely burnt. Once ejected, they "flash", causing irregularities in the exhaust. Solid-fuel motors are notorious for having unsteady thrust towards the end of their burn also - it becomes more and more difficult to control the burn surface as the original core shapes disappear. -- {hpda, uwmcsd1}!sp7040!obie!wes "How do you make the boat go when there's no wind?" -- Me --
wes@obie.UUCP (Barnacle Wes) (10/07/88)
In article <5488@ecsvax.uncecs.edu>, ruslan@ecsvax.uncecs.edu (Robin C. LaPasha) writes: > Tonite on the news I heard that NASA had found no evidence of a burn-through > fire on the recovered SRBs. Let us frigging hope they're right. > Geez, how could you have burn-through with the new flange and three-ring > system? If it happened, we can all look foward to another two and a half > years of frustration and (hopefully) the death sentence for the managers > at Morton Thiokol. The previous burn-throughs noted on the SRBs (yes, there *were* previous burn-throughs) did not occur in the flanges and o-ring assemblies. The burn-throughs occurred in the case walls near the point where the case skin flared out to accept the flange. The flanges are much stiffer than the case walls, and this causes flexing during the flight. The case walls crack due to the flexing, creating a weak spot. The internal pressures of the booster will cause a burn-through at this point IF the crack occurs early enough in the flight. I'm sorry I don't have the reference for this information with me right now, I have it at work. I can post it (or e-mail it) if anyone is interested. Note that this design flaw in the SRBs still exists, and may even be WORSE with the new thicker, stronger, and STIFFER flange assemblies. -- {hpda, uwmcsd1}!sp7040!obie!wes "How do you make the boat go when there's no wind?" -- Me --
henry@utzoo.uucp (Henry Spencer) (10/10/88)
In article <215@obie.UUCP> wes@obie.UUCP (Barnacle Wes) writes: >The previous burn-throughs noted on the SRBs (yes, there *were* previous >burn-throughs) did not occur in the flanges and o-ring assemblies. The >burn-throughs occurred in the case walls near the point where the case >skin flared out to accept the flange... Say what?!? References, please. This contradicts both the Rogers report and all the AW&ST coverage of the post-Challenger investigations. I've never even heard of this theory. -- The meek can have the Earth; | Henry Spencer at U of Toronto Zoology the rest of us have other plans.|uunet!attcan!utzoo!henry henry@zoo.toronto.edu
alastair@geovision.uucp (Alastair Mayer) (10/11/88)
In article <1988Oct5.170846.8023@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >In article <417@geovision.UUCP> alastair@geovision.UUCP (Alastair Mayer) writes: >>All of which makes me a bit skeptical about some proposed designs >>for 'aft cargo carriers' to be attached at the base of the ET. > >Why? Almost any aft cargo carrier is going to be less heat-sensitive than >the liquid hydrogen that's inside that part of the tank now. Not a bad point, but consider: the hydrogen at the base of the tank is thermally closely coupled to the rest of the hydrogen in the tank - that's quite a big heat sink; an aft cargo carrier, stuck on the bottom of the tank, is going to be that much *closer* to the hot exhaust plumes. There are also the noise and vibration problems, which probably don't bother hydrogen much. But it may not be that bad. I didn't say they wouldn't work, just that I was a bit skeptical. ------------------------------------------------- .signature file out for refurbishment