From owner-freebsd-chat Mon Feb 3 21:37:28 2003 Delivered-To: freebsd-chat@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id AB83937B401 for ; Mon, 3 Feb 2003 21:37:26 -0800 (PST) Received: from rwcrmhc53.attbi.com (rwcrmhc53.attbi.com [204.127.198.39]) by mx1.FreeBSD.org (Postfix) with ESMTP id 062D743F85 for ; Mon, 3 Feb 2003 21:37:26 -0800 (PST) (envelope-from swear@attbi.com) Received: from localhost.localdomain (unknown[12.242.158.67]) by rwcrmhc53.attbi.com (rwcrmhc53) with ESMTP id <20030204053721053003m8m6e>; Tue, 4 Feb 2003 05:37:22 +0000 Received: from localhost.localdomain (localhost [127.0.0.1]) by localhost.localdomain (8.12.6/8.12.5) with ESMTP id h145aR5F087859 for ; Mon, 3 Feb 2003 21:36:27 -0800 (PST) (envelope-from swear@attbi.com) Received: (from jojo@localhost) by localhost.localdomain (8.12.6/8.12.5/Submit) id h145aMWA087856; Mon, 3 Feb 2003 21:36:22 -0800 (PST) (envelope-from swear@attbi.com) X-Authentication-Warning: localhost.localdomain: jojo set sender to swear@attbi.com using -f To: Subject: Re: oh my god the nasa shuttle blewup References: <200302031346.34040.jrhoden@unimelb.edu.au> <49650.198.137.241.11.1044283121.squirrel@m.vocito.com> From: swear@attbi.com (Gary W. Swearingen) Date: 03 Feb 2003 21:36:21 -0800 In-Reply-To: Message-ID: Lines: 29 User-Agent: Gnus/5.0808 (Gnus v5.8.8) XEmacs/21.1 (Cuyahoga Valley) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-freebsd-chat@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org > it could have been any number of things. With highly-engineered systems like the shuttle, the number is usually about 3 or 4, almost never 1. Like: poorly-applied (1) insulation blows off, airstream blows it against typical tile (with huge force of airstream against foam, not just 2.67 lb at fairly low relative speed), knocking it loose. Re-entry pops it out, taking poorly-applied tile (2) just behind with it. Two-tile strip allows sufficient flow of hot gases to eat under next tile, etc., allowing heat to over-warm wing spar with some hidden corrosion (3) common to the Cape area and straining under the atypical wing loading (4) of the heavy old shuttle with the huge SpaceHab module and the 2.0 G loads created by speed-sheding S-turns, causing wing to break off. Actually, from what I heard today I suspect that there was a burn- through just behind the leading edge between the wheel well and the fuselage, where the pressure and tempurature were so much as to burn right through the upper skin, accounting for the raised temps measured on the left side of the fuselage. Airflow disruption and flapping edges of holes increase drag on that side, causing stability problems. Heat from inside allow more skin/tiles to peel until craft goes unstable (probably from burnt control system, possibly just from abnormal aero-forces), breaking up quickly thereafter. (I remember from 20 years ago reading that aero-control is extremely precarious and tricky in such thin air and high speeds -- so much so that during some portions of the flight, the flaperons must be moved in the "wrong" direction to achieve the right effect. They said today that the attitude rockets fired for a couple of seconds shortly before loss of signals to help the aero-control surfaces keep the thing under control.) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message