rnoe@urbana.mcd.mot.com (Roger Noe) (04/06/90)
In article <9535@ingr.com>, whitehrc@ingr.com (Robert C. Whitehead) writes: > "NASA would blow the Shuttle up." Well, they might indeed detonate the range safety devices on both the SRBs and the ET, but last I heard there were no range safety devices on the orbiter vehicle itself. Without the SRBs and no fuel from the ET, the orbiter is sort of a brick, unless it's in a controlled glide, in which case there isn't much need to "blow up the shuttle". The range safety devices don't even blow anything up, they're thrust-termination packages. They open up the SRBs so that the chamber pressure drops abruptly. The ET range safety device dumps the liquid fuel out, starving the main engines. Neither device would directly blow anything up. But the sudden deceleration would very probably cause the orbiter vehicle to disintegrate, just like Challenger. > "If the Shuttle has one SRB light without the other, the > shuttle is headed for either Orlando or Miami. The same > signal that lights the SRBs blows the holddown bolts on > the frame. So to prevent millions of dollars in collateral > damage and the loss of possibly hundreds of lives, the Range > Safety Officer (RSO) would destroy the Shuttle. So the shuttle is headed for Orlando or Miami on one SRB? It must be going by the highway, then, because that thing is not going to stay in the air (if it could even get there in the first place) for very long without both SRBs lit. If all the igniters on one SRB fail, the whole stack is just going to topple over in a big fireball since the ET is going to split wide open. By the way, if the shuttle were to auger into Space Mountain at Disneyworld, the potential loss of human lives is measured in the thousands, not mere hundreds. > "If the Shuttle deviates from its planned trajectory by more > than (a small percentage), the RSO has orders to destroy the > Shuttle. True, but the RSO doesn't have authority to act until the shuttle clears the launch tower, does he? It may even be the case that their antenna won't hit anything below a hundred feet or so; I don't know. > "And to answer the question about the force of the explosion: > If every gram of propellant (solid and liquid) were to be ignited > simultaneously, the maximum force of the explosion would be > approximately 1.2 megatons." In the first place, solids don't explode, even under some very unusual conditions. Secondly, 1.2 MEGAtons, as in TNT equivalent?! That's equivalent to a mass of one billion (10**9) kilograms of TNT? Is the mass of the shuttle's liquid fuel anywhere near a billion kilograms? Does a kg of H2+O2 have anywhere near the explosive force of a kg of TNT? > Takes a lot of courage to take a ride like that...... There are far bigger concerns when going up in the shuttle than "What if the RSO has to kill us?" If the RSO needs to act, then the astronauts are probably already going to die, whether or not range safety does it. The only thing in doubt is how many people and how much real estate they're going to take with them. -- Roger Noe Motorola Microcomputer Division, Urbana Design Center Phone: 217 384-8536 1101 East University Avenue, Urbana, IL 61801 USA Internet: rnoe@urbana.mcd.mot.com UUCPnet: uiucuxc!udc!rnoe Latitude/Longitude: 40:06:55 N./88:11:40 W.
whitehrc@ingr.com (Robert C. Whitehead) (04/06/90)
There's been some dicussion as to whether or not the figure of 1+ megatons explosive potential for the Shuttle is accurate. So to try and lay any doubts to rest, I called my source (aka my brother-in-law) again and asked for clarification. As I understand it, each SRB contains 1.1 megapounds of propellant, for a total of 2.2 megapounds. The ET hold 2.725 megapounds of hydrogen and oxygen for propellant. Now, I've been _told_ that the propellant used in the SRBs has a potential of 5:1; that is, each pound of propellant, if it exploded completely, has the explosive force of five pounds of TNT. Similarly, each pound of hydrogen or oxygen has a potential of 10:1. Well, by my figures, that means that the propellant would generate 11 megapounds of explosive force, and the hydrogen and oxygen would generate 27.250 megapounds of force, for a total of 38.250 megapounds. Dividing by 2000, I arrive at the figure 19,125 tons explosive force. I'm sure you'll agree that this figure is significantly different. When I pointed this out to said relative, he offered the following qualification: "Realize that we're talking about best-case burns, here. If *all* the propellant and *all* the hydrogen and *all* the oxygen ignited and burned at the same time, the total *potential* is 1.2 megatons. Real-world, you'd probably get about one-tenth that, because of the difference in burn rates." In any event, the resulting fireball could easily reach three miles in diameter; that's why NASA doen't normally let anyone within twelve miles of the Shuttle when it launches. I asked him to check his figures; stay tuned for the answer. ---------------------------- | 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!
pat@grebyn.com (Pat Bahn) (04/06/90)
IF anyone wants to check, Spectrum magazine did an article on the shuttle in mid 87. In there they stated that if the shuttle were to explode on the pad, under the right weather conditions, it would be equivalent to a 1.2 megaton warhead going off. This would require a thermal inversion to reflect shock back to the ground. This is not necessary the same as 1.2 million tonnes of TNT going off, but would create the same blast effect in the near vicinity. Hence, the evacuation of staff and the Large, Thick blockhouses for command personell. This is why all vieing areas are a few miles off. Said shockwave would thoroughly destroy the launch facility and damage nearby towers. read teh article for more detail. -- ============================================================================= Pat @ grebyn.com | If the human mind was simple enough to understand, 301-948-8142 | We'd be too simple to understand it. =============================================================================
henry@utzoo.uucp (Henry Spencer) (04/06/90)
In article <1161@urbana.mcd.mot.com> rnoe@urbana.mcd.mot.com (Roger Noe) writes: >Does a kg of H2+O2 have anywhere near the explosive force of a kg of TNT? Rather more, actually. However, the original poster did slip a decimal point. -- Apollo @ 8yrs: one small step.| Henry Spencer at U of Toronto Zoology Space station @ 8yrs: .| uunet!attcan!utzoo!henry henry@zoo.toronto.edu
pjs@aristotle.JPL.NASA.gov (Peter Scott) (04/07/90)
In article <19521@grebyn.com>, pat@grebyn.com (Pat Bahn) writes: > > IF anyone wants to check, Spectrum magazine did an article on the > shuttle in mid 87. In there they stated that if the shuttle were > to explode on the pad, under the right weather conditions, it would > be equivalent to a 1.2 megaton warhead going off. > > This would require a thermal inversion to reflect shock back to > the ground. This still has to be outta whack. A NASA study I read ages ago said that the worst scenario they could imagine was the entire stack plowing into the ground at high speed. The force of the vehicle above the point of impact would contain the explosion for an equivalent effect of 10kT, half the Hiroshima bomb. A megaton warhead will devastate a medium city. This is news. This is your | Peter Scott, NASA/JPL/Caltech brain on news. Any questions? | (pjs@aristotle.jpl.nasa.gov)
rick@ofa123.FIDONET.ORG (Rick Ellis) (04/08/90)
In a message of <Apr 03 17:28>, Larry Wall (lwall@jpl-devvax.JPL.NASA.GOV ) writes:
LW> Uh, numeracy check. Did he mean 1.2 megapounds, or 1.2 kilotons?
LW>
LW> A loaded space shuttle stack only weighs about 2.2 kilotons. I don't
LW> think solid fuel and H2/O2 is THAT much more powerful than TNT.
SRB propellant masses about 1.1 million pounds. (for each SRB)
--
Rick Ellis
...!{dhw68k,zardoz,lawnet,conexch}!ofa123!rick rick@ofa123.FIDONET.ORG
714 544-0934 2400/1200/300henry@utzoo.uucp (Henry Spencer) (04/08/90)
In article <9634@ingr.com> whitehrc@ingr.com (Robert C. Whitehead) writes: >In any event, the resulting fireball could easily reach >three miles in diameter; that's why NASA doen't normally >let anyone within twelve miles of the Shuttle when it >launches. Uh, both launch control and the closest observing sites are about three miles away. Twelve miles would probably take you well outside the KSC perimeter. And the three-mile limit is more a question of debris range than of fireball diameter. -- Apollo @ 8yrs: one small step.| Henry Spencer at U of Toronto Zoology Space station @ 8yrs: .| uunet!attcan!utzoo!henry henry@zoo.toronto.edu
lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall) (04/10/90)
In article <109.261E583A@ofa123.FIDONET.ORG> rick@ofa123.FIDONET.ORG (Rick Ellis) writes: : In a message of <Apr 03 17:28>, Larry Wall (lwall@jpl-devvax.JPL.NASA.GOV ) writes: : : LW> Uh, numeracy check. Did he mean 1.2 megapounds, or 1.2 kilotons? : LW> : LW> A loaded space shuttle stack only weighs about 2.2 kilotons. I don't : LW> think solid fuel and H2/O2 is THAT much more powerful than TNT. : : SRB propellant masses about 1.1 million pounds. (for each SRB) Well, yes, of course. That's about .55 kilotons. What are you getting at? Me, I was merely trying to indicate that the original figure was off by about 3 orders of magnitude. I was using the mass of the whole shuttle stack as an upper limit on the amount of combustibles the STS carries. I was assuming that the energy in the propellants is not very different from the amount of energy in a corresponding amount of TNT, which is the active ingredient in the usual interpretation of "megatonnage". All reasonable estimates for a mere numeracy check, no? If you were trying to answer my mostly rhetorical question, you forgot to include the H2/O2, and the conversion between the two fuels and TNT. Sorry I'm so snippy today. Must have been the full moon... Larry Wall lwall@jpl-devvax.jpl.nasa.gov