Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site alice.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!alice!alb From: alb@alice.UUCP (Adam L. Buchsbaum) Newsgroups: net.columbia Subject: Launch Aborted Message-ID: <3987@alice.UUCP> Date: Sat, 13-Jul-85 01:40:18 EDT Article-I.D.: alice.3987 Posted: Sat Jul 13 01:40:18 1985 Date-Received: Sat, 13-Jul-85 16:40:16 EDT Organization: Bell Labs, Murray Hill Lines: 16 The Challenger's launch attempt was aborted today, just three seconds before SRB ignition. In a near replay of the abort last summer, a valve that regulates the flow of hydrogen into the Number 2 Engine did not respond to its primary control circuit. A backup circuit sent the proper command 40 milliseconds after the failure was detected, but by that time, the ground sequence computer decided to abort the launch -- NASA rules forbid a launch unless all systems, including redundancies, are functioning, so that backups will be available once in flight. At the time of the abort, two engines were at full power, while the Number 2 Engine was near it. A water spray system, installed after last summer's abort and proceeding fire, activated, but there was no fire. NASA said the launch will be delayed at least 7 to 10 days while an assessment of the problem is made.