 +_____________________________________________________________________
 ] AUTHOR:            ]                             ] DR:              ]
 ] R. BARRETT         ]    PASS PROGRAM NOTE        ]     37549   *    ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE: SEPT. 1987 ]
 ] VER/282-7385       ]      RELEASE NOTE( )        ]                  ]
 ]____________________]_____________________________]__________________]
 ] OI/FLIGHT EFFECTIVITY:        ]  USER AFFECTED:                     ]
 ] OI02 AND SUBS                 ]  CREW (X)  GROUND (X)  DUMP ONLY ( )]
 ]_______________________________]_____________________________________]
 ]        MAJOR SOFTWARE AREA:       ] OPS MODES AFFECTED:             ]
 ]SSW ( )  GNC (X)  VU ( )  SM/PL ( )] G2, G3                          ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA: IMU, IPL, ORBIT                                  ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS: 4.38                                           ]
 ]_____________________________________________________________________]
 ] TITLE:                                                              ]
 ] IMU "SOFTWARE" OPERATE MODE INITIALIZATION AFTER AN ORBIT IPL       ]
 ]_____________________________________________________________________]
 ] DESCRIPTION: * 44246                                                ]
 ]                                                                     ]
 ] WHEN AN IPL IS PERFORMED ON-ORBIT AFTER LOSING THE MFB, SEVERAL BIT ]
 ] STRINGS USED BY THE IMU SOP TO DETERMINE WHETHER OR NOT TO PROCESS  ]
 ] IMU DATA WILL NOT BE PROPERLY SET. SINCE THE ATTITUDE PROCESSOR     ]
 ] DOES NOT USE THE OPERATE STATUS TO DETERMINE WHICH IMU'S ARE GOOD,  ]
 ] THE IMU DATA GOOD FLAGS ARE NOT AFFECTED BY THIS SITUATION. IN      ]
 ] OPS 2, THE ORBIT DAP COMES UP IN AUTO, AND BASED ON ATT PROC        ]
 ] INPUTS, MAY ERRONEOUSLY FIRE JETS, AND THE ADI RATE NEEDLES WILL    ]
 ] MOVE IN "ANTICIPATION" OF RATES EXPECTED FROM RCS FIRE CMD'S. THIS  ]
 ] WILL BE MISLEADING TO THE CREW; THE IMU SOP WILL NOT ACTUALLY       ]
 ] BE PROCESSING ANY IMU DATA.                                         ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ] USER RESPONSE:                                                      ]
 ]                                                                     ]
 ] SELECTION OF THE MANUAL DAP MODE AND PULSE SUBMODE FOR ALL ROTATION ]
 ] AXIS WILL PREVENT RCS FIRINGS. TO INITIALIZE THE BIT STRINGS        ]
 ] CORRECTLY, THE CREW MUST PRO INTO OPS G2 OR G3, BRING UP THE IMU    ]
 ] ALIGN DISPLAY (AND IF NECESSARY ENTER OPERATE COMMANDS FOR THE      ]
 ] IMU'S WHICH ARE DESIRED TO BE IN THE OPERATE MODE -- SEE TABLE).    ]
 ] THIS MUST BE DONE BEFORE COAS DATA IS TAKEN FOR IMU ALIGNMENTS.     ]
 ] THIS PROCEDURE WILL INSURE PROPER IMU SOP INITIALIZATION IN ALL     ]
 ] POSSIBLE SITUATIONS FOLLOWING AN ORBIT IPL.                         ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 @



 DR37549
 +_____________________________________________________________________
 ]                       SUPPLEMENTAL SHEET                            ]
 ]_____________________________________________________________________]
 ] AUTHOR:            ]                             ] DR:              ]
 ] R. BARRETT         ]    PASS PROGRAM NOTE        ]     37549   *    ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE: SEPT. 1987 ]
 ] VER/282-7385       ]      RELEASE NOTE( )        ]                  ]
 ]____________________]_____________________________]__________________]
 ] TITLE:                                                              ]
 ] IMU "SOFTWARE" OPERATE MODE INITIALIZATION AFTER AN ORBIT IPL       ]
 ]_____________________________________________________________________]
 ]USER RESPONSE:                                                       ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ]IMU STATE     ]FLIGHT CRITICAL OUTPUT]MINIMUM ACTION REQUIRED        ]
 ]PRIOR TO      ]DISCRETE INIT-        ]                               ]
 ]ORBIT IPL     ]IALIZATION IN OPS 2   ]                               ]
 ]              ]OR 3 CONTROL SEGMENT  ]                               ]
 ]--------------]----------------------]-------------------------------]
 ]OPERATE       ]SUCCESSFUL            ]1. CALL UP IMU ALIGN DISPLAY   ]
 ]--------------]----------------------]-------------------------------]
 ]OPERATE       ]FAILED (SEE NOTE)     ]1. CALL UP IMU ALIGN DISPLAY   ]
 ]              ]                      ]2. ENTER OPERATE COMMANDS FOR  ]
 ]              ]                      ]   ALL IMU'S                   ]
 ]--------------]----------------------]-------------------------------]
 ]STANDBY       ]NOT APPLICABLE        ]1. CALL UP IMU ALIGN DISPLAY   ]
 ]              ]                      ]2. ENTER OPERATE COMMANDS FOR  ]
 ]              ]                      ]   ALL IMU'S                   ]
 ]______________]______________________]_______________________________]
 ]                                                                     ]
 ] NOTE: FLIGHT CRITICAL OUTPUT DISCRETE INITIALIZATION WILL FAIL IF   ]
 ]       THE PASS DOES NOT HAVE CONTROL OF THE FLIGHT CRITICAL MDM'S   ]
 ]       DUE TO BFS ENGAGED.                                           ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]IBM: WYATT COOPER         DATE 7/28/88 ]                             ]
 ]    --------------------      ---------]                             ]
 ]SSD: SAM ANKNEY           DATE 7/28/88 ]                             ]
 ]    --------------------      ---------] RW MOOREHEAD        7/30/88 ]
 ]PF MGR: JOE THIBODEAU     DATE 7/29/88 ]------------------- -------- ]
 ]       -----------------      ---------] CHAIRMAN, SASCB      DATE   ]
 ]_______________________________________]_____________________________]
 @



