Jun 23 1984
From The Space Library
June 23-27: NASA began on June 23 the countdown at Cape Canaveral for the maiden flight of the Space Shuttle Discovery. This twelfth flight would carry Henry Hartsfield, commander, who was pilot on STS-4; Michael Coats, pilot; mission specialists Judith Resnik, Steven Hawley, and Richard Mullane; and payload specialist Charles Walker of McDonnell Douglas, the first payload specialist for private industry. Originally scheduled for launch on June 22, NASA had delayed liftoff when workers inspecting the orbiter's rocket motors following a test firing found that a heat shield inside a high-pressure pump in engine No. 1 had "debonded" and pulled away slightly from the wall of a chamber that contained superheated gases during launch. This necessitated replacement of one of the main engines, a three-day job that would delay launch until at least June 25.
The flight of Discovery was delayed on June 25 for at least 24 hours when its backup navigating computer failed less than 30 minutes before takeoff. Though it was not operational in space, the fifth backup computer was used during ascent to "watchdog" the other computers during the critical first 10 minutes of flight.
Four seconds from launch on June 26, the flight of Discovery was automatically aborted by a computer due to malfunctioning of a fuel valve on the rear starboard engine, causing the engine to catch fire. The fire was extinguished after three attempts with heavy sprays of water. NASA placed Hartsfield and his five-member crew on leave for two days after experiencing this first launch abort in 12 Space Shuttle missions and only the second launch abort in American manned spaceflight history. Thomas E. Utsman, Shuttle operations manager at KSC, said that he had no idea when the maiden flight of Discovery could be rescheduled. It depended, he said, on how much damage had been done to the malfunctioning engine that caught fire and to the Space Shuttle's protective tiles from the high-speed water jets that extinguished the fire on the aft part of the fuselage. Utsman said that the fire may have burned through the heat shield on the engine nozzle, meaning that the entire engine would have to be replaced.
NASA announced on June 27 that Discovery's maiden flight would not be attempted for at least two weeks in order to verily all three main engines. John Talone at KSC said, "I don't think we're talking about mid-July before we can get to the point of launching again." Talone said that the only serious question remaining about the aborted launch was why the valve stayed closed when commanded to start the liftoff firing sequence. When the valve failed to open, a backup actuator automatically started the opening sequence, and the valve opened soon enough for the engine to build full power, although it did not. He said that Discovery probably would have reached orbit, but mission rules said that a Space Shuttle could not lift off without redundant valve, and when the Shuttle's main computer sensed that one actuator system was out, the computer ordered engine cutoff. Photographic inspection of Discovery showed remarkably little damage from fire that broke out below the main engine nozzles after engine shutdown. The only structural damage to the Space Shuttle airframe was the speed brake just below the tail and half of the brake's protective enamel was scorched off. (W Post, June 23/84, A-3, June 25/84, A-7, June 26/84, A-1, June 27/84, A-3)
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