Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!asuvax!mcdphx!udc!rnoe From: rnoe@urbana.mcd.mot.com (Roger Noe) Newsgroups: sci.space.shuttle Subject: Re: Single SRB Ignition Keywords: if the worst should happen Message-ID: <1161@urbana.mcd.mot.com> Date: 5 Apr 90 23:58:41 GMT References: <9535@ingr.com> Organization: Motorola Microcomputer Division, Urbana, IL Lines: 62 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.