Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!elroy!devvax!smythsun!david From: david@smythsun.JPL.NASA.GOV (David Smyth) Newsgroups: sci.space.shuttle Subject: Re: Orbiter/SRB separation Message-ID: <2198@devvax.JPL.NASA.GOV> Date: 6 Jun 88 19:59:18 GMT References: <50665@ti-csl.CSNET> <2170@devvax.JPL.NASA.GOV> Sender: news@devvax.JPL.NASA.GOV Reply-To: david@smythsun.JPL.NASA.GOV (David Smyth) Organization: Jet Propulsion Laboratory, Pasadena, CA. Lines: 23 In article <2170@devvax.JPL.NASA.GOV> lwall@devvax.JPL.NASA.GOV (Larry Wall) writes: >In article <50665@ti-csl.CSNET> DMeyer@mips.csc.ti.com (Dane Meyer) writes: >: Why? The SSME's *are* throttlable, and there is some on-board fuel which >: normally is used for final insertion into orbit, as well as the subsequent >: de-orbit burn. So, the SSME's could be throttled down to some suitable >: level, and be allowed to burn while the disconnect/separation is accomplished. > >No doubt there will be others who say this, but the on-board fuel is >hypergolic and is not fed to the SSME's. If you look carefully you'll see >a couple extra nozzles sticking out the back. The SSME's must be shut >down before separation or their various components will diverge when the first >bubble comes through and the turbos suddenly have nothing to slow them down. So what if the SSMEs disintegrate? We are talking about an emergency, where the current result would be the loss of the entire vehicle. As long as the airframe is not damaged by their disintegration, it may still be an acceptable abort procedure. It sounds like it would work to throttle back gradually, and when the SSMEs are pushing as hard as the SRBs on the ET, and therefore the loads on the connecting struts are minimized, that perhaps the connections could be blown. The SSMEs would then breakup, and the Orbiter could glide down, possibly with the crew parachuting out since ditching is not survivable.