Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!elroy!devvax!lwall From: lwall@devvax.JPL.NASA.GOV (Larry Wall) Newsgroups: sci.space.shuttle Subject: Re: Orbiter/SRB separation Message-ID: <2201@devvax.JPL.NASA.GOV> Date: 6 Jun 88 20:55:06 GMT References: <50665@ti-csl.CSNET> <2170@devvax.JPL.NASA.GOV> <2198@devvax.JPL.NASA.GOV> Reply-To: lwall@devvax.JPL.NASA.GOV (Larry Wall) Organization: Jet Propulsion Laboratory, Pasadena, CA. Lines: 34 In article <2198@devvax.JPL.NASA.GOV> david@smythsun.JPL.NASA.GOV (David Smyth) writes: : 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. Maybe. But disintegrating turbos make lots of shrapnel. And there's a lot of other things back there that are critical to controlled flight. Like the control surfaces, the hydraulics to them, and particularly the APUs to power the hydraulics. And some of the tanks of hypergolics that fuel the APUs. If those go, you can probably kiss the whole back end goodbye. If we're going to plan a disintegration, it seems to me that we've already got a good idea how an orbiter breaks up. Revive the idea of hanging a parachute on the cabin, but don't worry about the pyrotechnics to separate it from the rest of the orbiter--they appear to be unnecessary, since aerodynamical forces will do the job nicely for you. The parachute doesn't even necessarily have to slow down the cabin enough for a survivable landing. As long as the crew has sufficient oxygen to get to bail-out altitudes, and a cabin stabilized by a small drogue chute, that should be sufficient. There's another thing: it may not be possible for the orbiter to pull away from the stack at all. In the Navy they discovered that they have to be REAL careful about running two ships next to each other, because the passage between the ships makes an excellent venturi, and sucks the two ships together. It may be that the SRBs *must* be peeled off sideways first (note that they have tractor rockets) in order to reduce the aerodynamic cross-section of the stack, before the orbiter can separate. Also, the ET is ordinarily dumped at a much higher altitude where the wind between the orbiter and the stack will be considerably less. On the other hand, I may be all wet. Larry Wall lwall@jpl-devvax.jpl.nasa.gov