whitehrc@ingr.com (Robert C. Whitehead) (04/06/90)
In article <10556.1574.forumexp@mts.rpi.edu>, Greg_d._Moore@mts.rpi.edu (Commander Krugannal) writes: > > Above, Robert writes that if the Shuttle deviates to far > from course, the Range Safety Officer would blow it up. > This HAS been done. The Range Safety Officer, upon gaining > information on Challanger, realized that the shuttle was > unrecoverable and uncontrollerable and detonated charges in the > ET and SRB's. Not true. The ET range safety charges were found intact after Challenger. > Actually, to state the the RSO would blow the shuttle up is > a misnomer. There is a line of charges that runs along the > ET. The idea is simply to open a large hole and very quickly > depressurize the tank and dump the fuel. As long as this > did not hit a flame source (i.e. the SRB's or SSME's) the > shuttle would survive. I find your argument specious. We've already stipulated that one SRB is lit; therefore the chances that a flame source is not present are two: fat and slim. Care to explain how high-velocity explosive is going to be flameless? Hell, if the RSO hits the Button, the ET, SRBs, orbiter, and the astronauts are *gone*, repeat, *gone*! Write the obits! NASA has already said, and every engineer I can collar confirms, that from the moment the SRB(s) light(s) until they (it) separate(s), there is no safe way home. Since the same signal that lights the SRBs blows the holddown bolts, if only one SRB lights, the astronaut corps is going to lose some good friends. ---------------------------- | Robert C. (Bob) Whitehead | | --=rcw=-- | Intergraph Corporation, Huntsville | Direct Email Replies: | Disclaimer: Opinions expressed are | ingr!b32a!rw8024!bob | strictly mine ---------------------------- /> The Faith ( //------------------------------------------------------------( (*)OXOXOXOXO(*> * * * K N I G H T S * O F * C O L U M B U S * * * \ ( \\--------------------------------------------------------------) \> And The Right To Fight For It!
mdbomber@portia.Stanford.EDU (Matt Bartley) (04/07/90)
In article <1990Apr5.035158.23244@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >In article <10556.1574.forumexp@mts.rpi.edu> Greg_d._Moore@mts.rpi.edu (Commander Krugannal) writes: >> This HAS been done. The Range Safety Officer, upon gaining >> information on Challanger, realized that the shuttle was >> unrecoverable and uncontrollerable and detonated charges in the >> ET and SRB's. > >Well, he pushed his button all right, which blows everything -- there >is no capability to blow just the SRBs or just the ET -- but the ET was >already in pieces and so were its destruct systems. They were recovered >unexploded. The SRB destruct system functioned as planned. I thought after the explosion the SRB`s went flying away like bottle rockets. When I first saw what happened I thought they were burning pieces of the shuttle, but I later saw they were the engines. Doesn't sound like the destruct worked there. >> depressurize the tank and dump the fuel. As long as this >> did not hit a flame source (i.e. the SRB's or SSME's) the >> shuttle would survive... >In a catastrophic failure, especially with explosives involved, plenty of >ignition sources will inevitably be present. Note that Challenger did >not "explode" in any technical sense; it went to pieces and the fuel >burned. The orbiter was destroyed not by a blast wave, but by being >thrown violently out of control at Mach 3 when the ET fell apart. What first touched off the breakup? I thought the burnthrough of the SRB caused the external tank to explode, from either burning through tank and lighting off the H2, or heating and pressurizing the stuff until the tank burst. That of course took the orbiter with it. In the video, it seemed like the orbiter was blow to bits. It didn't look like the tank blew and then the orbiter flew into pieces like you said. It looked too fast for that. I thought the thing was vaporized. -- Internet: mdbomber@portia.stanford.edu Matt Bartley Bitnet: mdbomber%portia@stanford.bitnet Kirk: "Spock! Where the hell's that power you promised?" Spock: "One damn minute, Admiral." -- Star Trek IV : The Voyage Home
gwh@volcano.Berkeley.EDU (George William Herbert) (04/07/90)
In article <10884@portia.Stanford.EDU> mdbomber@portia.Stanford.EDU (Matt Bartley) writes: >>> This HAS been done. The Range Safety Officer, upon gaining >>> information on Challanger, realized that the shuttle was >>> unrecoverable and uncontrollerable and detonated charges in the >>> ET and SRB's. >> >>Well, he pushed his button all right, which blows everything -- there >>is no capability to blow just the SRBs or just the ET -- but the ET was >>already in pieces and so were its destruct systems. They were recovered >>unexploded. The SRB destruct system functioned as planned. > >I thought after the explosion the SRB`s went flying away like bottle rockets. >When I first saw what happened I thought they were burning pieces of the >shuttle, but I later saw they were the engines. Doesn't sound like >the destruct worked there. The RSO waited until it was clear what was happening. In particular, when the SRB's were determined to be headed back towards land [quite a bit after the intial explosion] the RSO detonated the charges. ******************************************************************************* George William Herbert JOAT For Hire: Anything, Anywhere: My Price UCB Naval Architecture undergrad: Engineering with a Bouyant Attitude :-) ------------------------------------------------------------------------------- gwh@ocf.berkeley.edu <= prefered [also gwh@soda.berk.. and maniac@garnet.berk..] Give me a billion dollars and two years and I'll build you a space station you'll never forget. "Pull up! NO, NOT THAT UP!" CRUNCH
henry@utzoo.uucp (Henry Spencer) (04/07/90)
In article <1990Apr6.234715.22061@agate.berkeley.edu> gwh@OCF.Berkeley.EDU (George William Herbert) writes: >The RSO waited until it was clear what was happening. In particular, when the >SRB's were determined to be headed back towards land [quite a bit after the >intial explosion] the RSO detonated the charges. One reason why he wasn't in a hurry was that it had originally been thought that loose SRBs would tumble, which would largely eliminate the threat of them running wild. Oops; didn't happen that way. In fact, 20-20 hindsight later determined that the SRBs probably were not a threat and nothing dire would have happened if the RSO had kept his finger off the button... but the man gets paid to make a decision without waiting for the benefit of hindsight. -- Apollo @ 8yrs: one small step.| Henry Spencer at U of Toronto Zoology Space station @ 8yrs: .| uunet!attcan!utzoo!henry henry@zoo.toronto.edu
henry@utzoo.uucp (Henry Spencer) (04/08/90)
In article <10884@portia.Stanford.EDU> mdbomber@portia.Stanford.EDU (Matt Bartley) writes: >What first touched off the breakup? I thought the burnthrough of the SRB >caused the external tank to explode, from either burning through tank and >lighting off the H2, or heating and pressurizing the stuff until the tank >burst... At about the same moment, (a) the external tank, having had a substantial flame playing on it for some seconds, suffered a major structural failure, and (b) the aft support struts for the SRB, exposed to the same flame, failed, and the SRB pivoted on its forward struts, mashing in the side of the tank near the top end. The hydrogen did not "light off", as far as is known, until the tank failed (in any case, it can't light off inside a tank with no oxidizer present), and tank pressures were not grossly outside normal bounds. There was no explosion, just a large fire as hydrogen from the disintegrating tank burned. >In the video, it seemed like the orbiter was blow to bits. It didn't look >like the tank blew and then the orbiter flew into pieces like you said. >It looked too fast for that. I thought the thing was vaporized. In a word, no. Read the Rogers Commission report, which based its conclusions on detailed studies of the technical evidence. Things do happen very quickly with major structural failure at hypersonic speeds. It is possible, although not certain, that the pivoting SRB struck the orbiter's wing as an additional contributing factor. The orbiter most certainly was not vaporized; in particular, the cabin held together well enough that the astronauts were alive (although probably unconscious) until water impact, and the TDRS payload was found more or less in one piece. Both the cabin and the main engines were identifiable in the photos immediately after the breakup; the Rogers report points them out. A good bit of the orbiter was reconstructed from salvaged debris, and probably most of it could have been if recovery efforts had been more persistent. -- Apollo @ 8yrs: one small step.| Henry Spencer at U of Toronto Zoology Space station @ 8yrs: .| uunet!attcan!utzoo!henry henry@zoo.toronto.edu
rick@ofa123.FIDONET.ORG (Rick Ellis) (04/09/90)
In a message of <Apr 04 04:37>, Commander Krugannal (Greg_d._Moore@mts.rpi.edu ) writes:
CK> Actually, to state the the RSO would blow the shuttle up is
CK> a misnomer. There is a line of charges that runs along the
CK> ET. The idea is simply to open a large hole and very quickly
CK> depressurize the tank and dump the fuel. As long as this
CK> did not hit a flame source (i.e. the SRB's or SSME's) the
CK> shuttle would survive. I believe Henry has already explained
CK> how the SRB's themselves would be detonated.
The are also charges on each SRB. The three (ET, and 21 SRBs) charges are
ganged together to that if any one is armed, they all arm. Ditto for firing.
--
Rick Ellis
...!{dhw68k,zardoz,lawnet,conexch}!ofa123!rick rick@ofa123.FIDONET.ORG
714 544-0934 2400/1200/300henry@utzoo.uucp (Henry Spencer) (04/09/90)
In article <1990Apr9.062158.21015@uokmax.uucp> mflawson@uokmax.uucp (Michael F Lawson) writes: >If there were another similar shuttle breakup today and by some miracle some >astronauts did remain conscious for a minute or so, would they be able to >get out of the cabin in free-fall? More specifically, would the emergency >hatch jettison system still work with no power to the cabin? And do they even >wear parachutes on the ascent? They now wear partial-pressure suits with oxygen systems, so they would remain conscious. And they now have parachutes. I'm a bit unsure about the hatch-jettison system, although some of those complications were meant to deal with bailing out in gliding flight and would be less necessary for getting out after an orbiter had disintegrated. -- Apollo @ 8yrs: one small step.| Henry Spencer at U of Toronto Zoology Space station @ 8yrs: .| uunet!attcan!utzoo!henry henry@zoo.toronto.edu
petej@phred.UUCP (Pete Jarvis) (04/10/90)
In article <10556.1574.forumexp@mts.rpi.edu> Greg_d._Moore@mts.rpi.edu (Commander Krugannal) writes: > > This HAS been done. The Range Safety Officer, upon gaining > information on Challanger, realized that the shuttle was > unrecoverable and uncontrollerable and detonated charges in the > ET and SRB's. The RSO did not detonate the charges in the ET. They were recovered intact. Only the SRB's were destroyed by RSO. Peter Jarvis..........
petej@phred.UUCP (Pete Jarvis) (04/10/90)
In article <1990Apr7.221851.14080@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: > >report points them out. A good bit of the orbiter was reconstructed from >salvaged debris, and probably most of it could have been if recovery >efforts had been more persistent. Challenger debris recovery went on until sometime in June. How much more persistent would you have them be? Peter Jarvis..........
john@frog.UUCP (John Woods) (04/10/90)
In article <10884@portia.Stanford.EDU>, mdbomber@portia.Stanford.EDU (Matt Bartley) writes: > I thought after the explosion the SRB`s went flying away like bottle rockets. > When I first saw what happened I thought they were burning pieces of the > shuttle, but I later saw they were the engines. Doesn't sound like > the destruct worked there. It took the RSO some time to blow up the SRBs (110.250 seconds after launch, 36 seconds after the explosion). I think there was some hope that they'd recover the SRBs whole, but the left SRB was headed toward a populated area. > What first touched off the breakup? T+72.497 SSME roll gimbal rates 5deg/sec T+72.525 Vehicle max +Y lateral acceleration (+.227g) Now, imagine being hit under the chin with a GREAT, BIG SLEDGEHAMMER being driven at Mach 3. You'd go to pieces, too ;-). -- John Woods, Charles River Data Systems, Framingham MA, (508) 626-1101 ...!decvax!frog!john, john@frog.UUCP, ...!mit-eddie!jfw, jfw@eddie.mit.edu
henry@utzoo.uucp (Henry Spencer) (04/11/90)
In article <121.261FF149@ofa123.FIDONET.ORG> rick@ofa123.FIDONET.ORG (Rick Ellis) writes: >The are also charges on each SRB. The three (ET, and 21 SRBs) charges are >ganged together to that if any one is armed, they all arm. Ditto for firing. One of the Rogers Commission's recommendations, in fact, was that it might be worth investigating the possibility of separate arming and firing. -- Apollo @ 8yrs: one small step.| Henry Spencer at U of Toronto Zoology Space station @ 8yrs: .| uunet!attcan!utzoo!henry henry@zoo.toronto.edu
henry@utzoo.uucp (Henry Spencer) (04/11/90)
In article <3035@phred.UUCP> petej@phred.UUCP (Pete Jarvis) writes: >>... A good bit of the orbiter was reconstructed from >>salvaged debris, and probably most of it could have been if recovery >>efforts had been more persistent. > >Challenger debris recovery went on until sometime in June. How much more >persistent would you have them be? "Persistent" wasn't quite the word I wanted, although it was the best one-word approximation I could think of. Debris recovery was aimed at investigating the disaster rather than at recovering every possible fragment; for example, I don't believe they tried to recover the TDRS, although they did locate it and verify that it seemed to be in one piece. -- Apollo @ 8yrs: one small step.| Henry Spencer at U of Toronto Zoology Space station @ 8yrs: .| uunet!attcan!utzoo!henry henry@zoo.toronto.edu
whitehrc@ingr.com (Robert C. Whitehead) (04/11/90)
I hope everyone remembers the basis for the argument about the Shuttle generating a 1.2 megaton blast if it were range-saftied on the pad. I finally got the definitive figures from my reliable source (aka my brother-in-law, who wrote the specs and redlines for the Range Saftey System on STS). I have appended them with the parameters of the explosion. TERMS: FIREBALL Defined as area of 27 pounds per square inch (psi) overpressure ZONE OF TOTAL DESTRUCTION Defined as area of 12 psi overpressure 100% STRUCTURAL DAMAGE AREA Defined as area of 8 psi overpressure 50% STRUCTURAL DAMAGE AREA Defined as area of 3.5 psi overpressure 10% STRUCTURAL DAMAGE AREA Defined as area of 1.7 psi overpressure 5% STRUCTURAL DAMAGE AREA (aka 50% casualty area, meaning that 50% of the people in this area die) Defined as area of 1.2 psi overpressure DEBRIS ZONE Defined as area of .7 psi overpressure OK, now that the nitpicking is out of the way and the terms are defined, we'll get on with it: CASE STUDY #1 Range Saftey declared on the pad; SRB and ET RS devices are triggered ASSUMING: Blast is at ground level, with 40% of the blast directed upward. 100% of all fuel (solid, hydrogen, and oxygen) is consumed in the blast at maximum possible rate of burn. FIREBALL = 891 feet radius ZONE OF TOTAL DESTRUCTION = 1,321' radius 100% STRUCTURAL DAMAGE AREA = 1,615' radius 50% STRUCTURAL DAMAGE AREA = 2,643' radius 10% STRUCTURAL DAMAGE AREA = 4,405' radius 5% STRUCTURAL DAMAGE AREA (aka 50% casualty area, meaning that 50% of the people in this area die) = 7,341' radius DEBRIS ZONE = 11,747' radius According to my sources, this compares favorably to the blast caused by 1 megaton of TNT. Notice that I said *blast*: this has nothing to do with the thermal or radiation effects of a thermonuclear device. I think that most people arguing with me are saying that a 1MT nuke is much more destructive. In a way, they're right, but it's only because a nuke has three dimensions of destruction (blast, fire, and radiation) whereas 1MT of TNT is a blast-only weapon. (Yes, I'll concede that if you detonated 1MT TNT, *something* would probably burn; I maintain, however, that TNT's thermal destruction capacity is negligible when compared to a nuke.) CASE STUDY #2 Range Safety declared on the pad; only the ET RS device triggers. Only the ET explodes. ASSUMING: Blast is at ground level, with 40% of the blast directed upward. FIREBALL = 589' radius ZONE OF TOTAL DESTRUCTION = 884' radius 100% STRUCTURAL DAMAGE AREA = 1,081' radius 50% STRUCTURAL DAMAGE AREA = 1.768' radius 10% STRUCTURAL DAMAGE AREA = 2,947' radius 5% STRUCTURAL DAMAGE AREA (aka 50% casualty area, meaning that 50% of the people in this area die) = 4,912' radius DEBRIS ZONE = 7,859' radius I'll be happy to pass on any objections, but I remind you that these figures come from the people who *build* the SRBs - United Technologies/USBI. ---------------------------- | Robert C. (Bob) Whitehead | | --=rcw=-- | Intergraph Corporation, Huntsville | Direct Email Replies: | Disclaimer: Opinions expressed are | ingr!b32a!rw8024!bob | strictly mine ---------------------------- /> ( //------------------------------------------------------------( (*)OXOXOXOXO(*> * * * K N I G H T S * O F * C O L U M B U S * * * \ ( \\--------------------------------------------------------------) \>
pjs@aristotle.JPL.NASA.gov (Peter Scott) (04/11/90)
In article <9689@ingr.com>, whitehrc@ingr.com (Robert C. Whitehead) writes: > I finally got the definitive figures from my reliable source > (aka my brother-in-law, who wrote the specs and redlines > for the Range Saftey System on STS). I have appended them with > the parameters of the explosion. >[...] > CASE STUDY #2 > > Range Safety declared on the pad; only the ET RS device triggers. > Only the ET explodes. I'd be curious to know where they get off speculating that the ET could blow up without setting off the SRBs. With a fireball of 589' radius, and considering that the SRBs have their own oxidizer mixed in with them and require little more than a spark to ignite, this seems an unlikely scenario indeed. This is news. This is your | Peter Scott, NASA/JPL/Caltech brain on news. Any questions? | (pjs@aristotle.jpl.nasa.gov)
dave@rnms1.paradyne.com (Dave Cameron (Consultant)) (04/12/90)
In article <9689@ingr.com> whitehrc@ingr.com (Robert C. Whitehead) writes: > >I finally got the definitive figures from my reliable source >(aka my brother-in-law, who wrote the specs and redlines >for the Range Saftey System on STS). I have appended them with >the parameters of the explosion. > >TERMS: [Defined as area of X psi overpressure] > 5% STRUCTURAL DAMAGE AREA (aka 50% casualty area, > meaning that 50% of the people in this area die) > Defined as area of 1.2 psi overpressure > >I'll be happy to pass on any objections, but I remind you that >these figures come from the people who *build* the SRBs - >United Technologies/USBI. Now Wait A Minute - somebody clearly misunderstood something. The accepted definition of casualty is injury, not death. Even with this change I wonder about that part. One of the first lessons to come out of WWII was how RESISTANT to overpressure the human body is. [The English government planned for way too many dead and way too few homeless and minor injuries for the bombing of London. After the first big raid they had a lot of unneeded coffins and a lot of basically unhurt people looking for shelter. ] [The structural damage numbers are reasonable for normal construction.] dave "thinkin about the unthinkable" cameron
whitehrc@ingr.com (Robert C. Whitehead) (04/12/90)
In article <1990Apr11.161459.14816@elroy.jpl.nasa.gov>, pjs@aristotle.JPL.NASA.gov (Peter Scott) writes: > In article <9689@ingr.com>, whitehrc@ingr.com (Robert C. Whitehead) writes: > > I finally got the definitive figures from my reliable source > > (aka my brother-in-law, who wrote the specs and redlines > > for the Range Saftey System on STS). I have appended them with > > the parameters of the explosion. > >[...] > > CASE STUDY #2 > > > > Range Safety declared on the pad; only the ET RS device triggers. > > Only the ET explodes. > > I'd be curious to know where they get off speculating that the ET could > blow up without setting off the SRBs. With a fireball of 589' radius, > and considering that the SRBs have their own oxidizer mixed in with them > and require little more than a spark to ignite, this seems an unlikely > scenario indeed. > > Peter Scott, NASA/JPL/Caltech Thanks for the catch, Pete... Granted; what I should have said is that the figures represented the amount of damage one could expect if the ET blew alone. The case study scenario was poorly worded. Let's just say that if, for some reason, NASA wanted to blow up a full ET, that's what you'd get (though God only knows why they'd want to blow up a good ET.....) ---------------------------- | Robert C. (Bob) Whitehead | | --=rcw=-- | Intergraph Corporation, Huntsville | Direct Email Replies: | Disclaimer: Opinions expressed are | ingr!b32a!rw8024!bob | strictly mine ----------------------------
henry@utzoo.uucp (Henry Spencer) (04/13/90)
In article <9689@ingr.com> whitehrc@ingr.com (Robert C. Whitehead) writes: >I hope everyone remembers the basis for the argument about >the Shuttle generating a 1.2 megaton blast if it were >range-saftied on the pad. > ... > 5% STRUCTURAL DAMAGE AREA (aka 50% casualty area, > meaning that 50% of the people in this area die) > Defined as area of 1.2 psi overpressure > ... >Range Saftey declared on the pad; SRB and ET RS devices are triggered > ... >5% STRUCTURAL DAMAGE AREA (aka 50% casualty area, >meaning that 50% of the people in this area die) = 7,341' radius Unfortunately, this *still* doesn't add up to 1.2MT. A quick spin of the old Nuclear Bomb Effects Computer (revised edition, 1964) (an AEC "publication" -- a circular slide rule -- based on data from The Effects of Nuclear Weapons) shows a yield just under 10 *kilo*tons to produce 1.2psi overpressure at 7341ft. This assumes a ground burst, the yield for optimum burst height is even smaller. (By comparison, the 1.2psi overpressure radius for a 1.2MT ground burst is *seven miles*.) That's a fairly good case; evidently an exploding rocket doesn't behave quite the same way as a nuclear bomb, because the yields for your higher- overpressure radii are even smaller, mostly down in the 2-3kT range. Could someone using an N.B.E.C. have read the distance scale, which is in miles, as thousands of feet instead? It's interesting that your radius is 7 thousand feet and the 1.2MT radius is 7 miles. And where did you get the idea that 50% of people die at 1.2psi?? T.E.o.N.W. estimates 50% fatalities at about *fifty* psi and negligible fatalities below about 35, although some injury to lungs is possible at 7psi or so in worst-case conditions. >According to my sources, this compares favorably to the blast >caused by 1 megaton of TNT. Can you identify your sources? They seem to disagree drastically with the numbers from the US government's bomb-effects experts. -- With features like this, | Henry Spencer at U of Toronto Zoology who needs bugs? | uunet!attcan!utzoo!henry henry@zoo.toronto.edu