D.2.2 Atlas Failure Narratives

The following narratives provide the available details about each Atlas failure since the
beginning of the Atlas program. The narratives are numbered to match the flight-
sequence numbers in Section D.2.1.                                     •

1.   4A, 11 June 57, Response Mode 4T, Flight Phase 1: Flight appeared normal for
     24.7 seconds when drop in fuel supply to B2 engine produced a drop in
     performance and shutdown Both engines moved to hardover in pitch to
     compensate for thrust asymmetry. The Bl engine failed at 27 seconds. A fuel fire
     was observed in aft end after thrust was lost. The missile continued to rise,
     reaching an altitude of 9,800 feet at 38 seconds. Missile was destroyed by safety
     officer 50.1 seconds after liftoff. Thrust unit and other hardware impacted about
     1/4 mile south of launch pad (105° flight azimuth).
2.   6A, 25 Sep 57, Response Mode 4, Flight Phase 1: Flight appeared normal until
     about 32.5 seconds after liftoff, when performance level of both engines dropped
     to 35% of normal. Both engines shut down at 37 seconds. Missile was destroyed
     at 63 seconds. Loss of thrust was due to loss of LOX regulator in the booster gas
     generator. Major components impacted about 8000 feet downrange and 1000 feet
     right of flight line.                                                  •

5.   13A, 7 Feb 58, Response Mode 4, Flight Phase 1: The B2 turbopump and engine
     stopped operating about 118 seconds due either to loss of 102 regulator reference
     pressure or a control-system failure. The Bl engine ceased to operate 0.3 second
     later. Failure was attributed to shorting of a vernier engine feedback transducer
     due to aerodynamic heating. Propellant sloshing that began building up at about
     100 seconds led to missile instability. Vehicle broke up at 167 seconds. Impact
     occurred about 280 miles downrange and about 3 miles crossrange.
6.   llA, 20 Feb 58, Response Mode 4T, Flight Phase 1: Vernier engine was hardover
     from 51.9 seconds to 89.4 seconds, then returned to null until 104 seconds, then
     went hardover again. Other systems appeared normal until 109.6 seconds, when
     divergent oscillations began in rate-gyro outputs and engine positions. All
     engines reached stops by 114.3 seconds and continued thereafter to oscillate
     between stops until loss of thrust at 124.8 seconds. Vehicle breakup occurred one
     second later. Probable cause of oscillation was a component failure in flight
     control system. Vehicle impacted about 105 miles downrange and 8 miles right of
     flight line.

7.   15A, 5 Apr 58, Response Mode 4, Flight Phase 1: Booster engines shut down
     prematurely at 105.3 seconds (instead of planned 127 seconds) due to Bl
     turbopump failure. Since Bl chamber pressure drives the gas generator, the B2
     turbopump and engine also stopped. Impact was 180 miles downrange and
     slightly left of flight line.


9/10/96                                   115                                        RTI