Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.3 alpha 4/15/85; site amd.UUCP Path: utzoo!linus!philabs!prls!amdimage!amdcad!amd!tc From: tc@amd.UUCP (Tom Crawford) Newsgroups: net.columbia Subject: Abort to Orbit Message-ID: <1605@amd.UUCP> Date: Tue, 6-Aug-85 09:46:48 EDT Article-I.D.: amd.1605 Posted: Tue Aug 6 09:46:48 1985 Date-Received: Sat, 10-Aug-85 20:30:35 EDT Organization: AMD Applications, Santa Clara, CA Lines: 54 Here are paragraphs from an article in Aug 5 Aviation Week. These are reproduced without permission. Abort-to-Orbit Incident Will Intensify Shuttle Engine Procedure Reviews Johnson Space Center- The premature shutdown of one of the shuttle orbiter Challenger's main engines that forced an abort to orbit last week was caused by a temperature sensor failure in the Rocketdyne engine rather that an actual problem with the propulsion system, shuttle managers believe. ... Lead ascent flight director Cleon Lacefield said a reexamination of data indicates that, had the second engine failed at a time when abnormal sensor readings were occurring in it, Challenger could still have achieved a safe but tenuous orbit. A second engine failure, however, would have caused the shuttle's 39-ton Martin Marietta external tank to fall on populated areas of Europe somewhere along a line stretching across central France, Switzerland, south of Milan or near Athens. ...5 min. 55 sec. Fullerton, piloting Challenger, rotated a switch on the instrument panel to the abort ATO position, then pushed an ajoining abort command button. This told the orbiter's computers that ATO procedures were now required. It immediately ignited Challenger's two Aerojet orbital maneuvering engines to dump 4,400 lbs. of OMS propellant so the remaining main engine thrust could be used more efficiently. 6 min - For 106 sec. Challenger's two OMS engines fired along with the two remaining main engines. The OMS engines provided an additional 12,000 lb. of thrust, but this was incidental to the abort situation. The requirement was to dump OMS propellant to lighten the load. ...... 8 min. 12 sec. Howard at the booster console saw sensors on the right main engine, one of two still firing, start to act improperly. She first saw the B-side fuel pump temperature sensor fail on the right engine, the same failure that started the center engine's problems.... 8 min 45 sec Lacefield had Richards radio Challenger, "Main engine limits to inhibit," an emergency call to prevent the second engine from failing if the temperature sensor data climbed higher. Fullerton immediately flipped a switch on the console, canceling out the protective circuitry in the engines that could have shut down the engines. Tom Crawford ...amd!tc