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Date: Tue, 3 Jul 84 10:19:23 EDT
From: Joe Pistritto <jcp@BRL-TGR.ARPA>
To:       Space-Enthusiasts@mit-mc.ARPA
Subject: Re:  SPACE Digest V4 #236

	From the July 2nd issue of Aviation Week, this summary of events
immediately after the aborted launch of Discovery:  All times are T+ times,
ie. seconds/minutes after intended launch.

	2 sec - "We have an RSLS abort" - Lockheed rep on launch console to NASA

	6 sec - "Ground Launch Sequencer safing in progress" - a reference to
		returning  range safety charges to disarmed condition

	12 sec - "Verify engine ignition is safe" - Lockheed test director

	17 sec - "Break - break - ground launch sequencer shows engine one
		not shut down" - indicating a possibly runaway engine, which
		caused several minutes of confusion before it was verified that
		one had never been ignited, (the sequence aborted before that)

	45 sec - "All engines are shut down" - test director

	49 sec - "We have a red light on engines two and three in the cockpit,
		  not on one" - Astronaut Hartsfield from Discovery, verifying
		  that one had not ignited.

	1 min. 59 sec. - "I think we are okay now, everything looks good,
		  safing is in progress, I think its finished"|y|yyyy||

	2 min. 30 sec. - "Ground launch sequencer safing is complete"

	3 min. 30 sec. - A controller radios test director Weinberg "Do you
		  know there is a small flame on tv monitor 58 on the main
		  engines?"  (it turned out to be engine #3)

	-- several minutes of discussion of fires around the vehicle followed,
	along with several instances where the water deluge system used to
	suppress the shock of launch was manually turned off and on.  Fires
	continued until 20 min. or so.  During this period, an emergceny
	evacuation of the crew was considered but not initiated.  Crew was
	evacuated at T+40 minutes using the crew access arm and the gantry

				Thought someone might like to know...

Date: Tue, 10 Jul 84 0:13:46 EDT
From: Joe Pistritto <jcp@BRL-TGR.ARPA>
To:       Space-Enthusiasts@mit-mc.ARPA
Subject: Fire after launch abort

As the article in Aviation Week which I summarized part of earlier
mentioned, there was indeed fire around Discovery after the abort, it was
caused by Hydrogen venting from the unstarted engine, (which was being
cycled into a firing sequence when the shutdown occurred, with the fuel
valve aready 10% open).  Also, to control pressures, the fuel and oxidyzer
line valves were alternately closed and opened to allow excess pressure to
vent.  The fire was merely this gas flaring off around the pad.  Since the
shuttle is covered with heat resistant tiles, it was in no danger, but
some of the control wiring to/from the gantry tower (as well as the tower
itself, and supporting structure under Discovery), probably was.  Hence
the use of the water deluge system to suppress the fire.  There were
numerous times in the 20 minutes after abort when the fire detectors on
level 1 and 2 of the gantry tower illuminated lights in the firing room
indication fire however, so it was a real problem.  (It was very difficult
to see the flames in TV or still photographs though, as gas fires are
typically very thin flames, (although sometimes very large in size)).


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