 +_____________________________________________________________________
 ] AUTHOR:            ]                             ] SMS: B27796      ]
 ] M. D. TAGGART      ]    BFS PROGRAM NOTE         ] DR:  109688      ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE:  3-18-97   ]
 ] BNA/(562)922-4372  ]      RELEASE NOTE ( )       ] REV A: 3-25-98   ]
 ]____________________]_____________________________]__________________]
 ] OI/FLIGHT EFFECTIVITY:        ]  USER AFFECTED:                     ]
 ]  OI-26 THROUGH OI-28          ]  CREW ( )  GROUND (X)  DUMP ONLY ( )]
 ]_______________________________]_____________________________________]
 ]           MAJOR SOFTWARE AREA:            ] OPS MODES AFFECTED:     ]
 ]BSL( ) BSS( ) GNC(X) SEQ( ) SM/SP( ) IPL( )]      1                  ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA: GUID & NAV                                       ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS: MG038104/3.2.2.3.8.1.4 ASCENT USER PARAMETER   ]
 ]                      INITIALIZATION                                 ]
 ]_____________________________________________________________________]
 ] TITLE: SIGNIFICANT GUIDANCE DIFFERENCES BETWEEN PASS AND BFS DUE TO ]
 ]        ON-BOARD DELTA PSI COMPUTATIONS                              ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:                                                        ]
 ]                                                                     ]
 ] IF LIFTOFF OCCURS AT EXACTLY T_GMTLO_PHASE, PASS AND BFS WILL TARGET]
 ] DIFFERENT LAUNCH PANES.  CONSEQUENTLY, PASS AND BFS WOULD CALCULATE ]
 ] DIFFERENT ASCENT TARGETS AND FLY DIFFERENT TRAJECTORIES.  EXCESSIVE ]
 ] STEERING DISCREPANCIES BETWEEN PASS AND BFS WOULD BE SEEN ON THE    ]
 ] BFS ASCENT TRAJ DISPLAY.  FURTHERMORE, BFS COULD GO UNCONVERGED.    ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ] USER RESPONSE:                                                      ]
 ]                                                                     ]
 ] LAUNCH AT OR CLOSE TO T_GMTLO_PHASE MUST NOT OCCUR.  TO ENSURE THE  ]
 ] DESIRED LAUNCH PANE, A NON-LAUNCH WINDOW AROUND T_GMTLO_PHASE MUST  ]
 ] BE ESTABLISHED.  LIFTOFF TIME SHOULD BE AT LEAST FOUR SECONDS BEFORE]
 ] OR TWO SECONDS AFTER T_GMTLO_PHASE.                                 ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]BNA:<S> JOHN T. AGRES     DATE 04/03/98]                             ]
 ]    --------------------      ---------]                             ]
 ]ASD:  ERIC C. BINGHAM     DATE 05/01/98]                             ]
 ]    --------------------      ---------] DARRELL E. STAMPER 05/04/98 ]
 ]PF MGR:  GENE BROWND      DATE 04/21/98]------------------- -------- ]
 ]       -----------------      ---------] CHAIRMAN, SASCB      DATE   ]
 ]_____________________________________________________________________]
 @

