STABLE ORBIT

Scanned pages: 525-532

STABLE_ORBIT.agc

# Copyright:    Public domain.
# Filename:     STABLE_ORBIT.agc
# Purpose:      Part of the source code for Colossus 2A, AKA Comanche 055.
#               It is part of the source code for the Command Module's (CM)
#               Apollo Guidance Computer (AGC), for Apollo 11.
# Assembler:    yaYUL
# Contact:      Hartmuth Gutsche <hgutsche@xplornet.com>.
# Website:      www.ibiblio.org/apollo.
# Pages:  525-532
# Mod history:  2009-05-10 HG    Started adapting from the Colossus249/ file
#                of the same name, using Comanche055 page
#                images 0525.jpg - 0532.jpg.
#
# This source code has been transcribed or otherwise adapted from digitized
# images of a hardcopy from the MIT Museum.  The digitization was performed
# by Paul Fjeld, and arranged for by Deborah Douglas of the Museum.  Many
# thanks to both.  The images (with suitable reduction in storage size and
# consequent reduction in image quality as well) are available online at
# www.ibiblio.org/apollo.  If for some reason you find that the images are
# illegible, contact me at info@sandroid.org about getting access to the
# (much) higher-quality images which Paul actually created.
#
# Notations on the hardcopy document read, in part:
#
#    Assemble revision 055 of AGC program Comanche by NASA
#    2021113-051.  10:28 APR. 1, 1969
#
#    This AGC program shall also be referred to as
#            Colossus 2A
# Page 525
# STABLE ORBIT RENDEZVOUS PROGRAMS (P38 AND P78)
#
# MOD NO -1    LOG SECTION - STABLE ORBIT - P38-P39
# MOD BY RUDNICKI.S  DATE 25JAN68
#
# FUNCTIONAL DESCRIPTION
#
#  P38 AND P78 CALCULATE THE REQUIRED DELTA V AND OTHER INITIAL
#  CONDITIONS REQUIRED BY THE AGC TO (1) PUT THE ACTIVE VEHICLE
#  ON A TRANSFER TRAJECTORY THAT INTERCEPTS THE PASSIVE VEHICLE
#  ORBIT A GIVEN DISTANCE, DELTA R, EITHER AHEAD OF OR BEHIND THE
#  PASSIVE VEHICLE AND (2) ACTUALLY PLACE THE ACTIVE VEHICLE IN THE
#  PASSIVE VEHICLE ORBIT WITH A DELTA R SEPARATION BETWEEN THE TWO
#  VEHICLES
#
# CALLING SEQUENCE
#
#  ASTRONAUT REQUEST THRU DSKY
#
#  V37E38E    IF THIS VEHICLE IS ACTIVE VEHICLE
#  V37E78E    IF OTHER VEHICLE IS ACTIVE VEHICLE
#
# INPUT
#
#  (1)  SOI MANEUVER
#
#    (A)  TIG  TIME OF SOI MANEUVER
#    (B)  CENTANG  ORBITAL CENTRAL ANGLE OF THE PASSIVE VEHICLE
#        DURING TRANSFER FROM TIG TO TIME OF INTERCEPT
#    (C)  DELTAR  THE DESIRED SEPARATION OF THE TWO VEHICLES
#        SPECIFIED AS A DISTANCE ALONG THE PASSIVE VEHICLE
#        ORBIT
#    (D)  OPTION  EQUALS 1 FOR SOI
#
#  (2)  SOR MANEUVER
#
#    (A)  TIG  TIME OF SOR MANEUVER
#    (B)  CENTANG  AN OPTIONAL RESPECIFICATION OF 1 (B) ABOVE
#    (C)  OPTION  EQUALS 2 FOR SOR
#    (D)  DELTTIME  THE TIME REQUIRED TO TRAVERSE DELTA R WHEN
#        TRAVELING AT A VELOCITY EQUAL TO THE HORIZONTAL
#        VELOCITY OF THE PASSIVE VEHICLE - SAVED FROM
#        SOI PHASE
#    (E)  TINT  TIME OF INTERCEPT (SOI) - SAVED FROM SOI PHASE
#
# OUTPUT
#
#  (1)  TRKMKCNT  NUMBER OF MARKS
#  (2)  TTOGO  TIME TO GO
#  (3)  +MGA  MIDDLE GIMBAL ANGLE
# Page 526
#  (4)  DSPTEM1  TIME OF INTERCEPT OF PASSIVE VEHICLE ORBIT
#      (FOR SOI ONLY)
#  (5)  POSTTPI  PERIGEE ALTITUDE OF ACTIVE VEHICLE ORBIT AFTER
#      THE SOI (SOR) MANEUVER
#  (6)  DELVTPI  MAGNITUDE OF DELTA V AT SOI (SOR) TIME
#  (7)  DELVTPF  MAGNITUDE OF DELTA V AT INTERCEPT TIME
#  (8)  DELVLVC  DELTA VELOCITY AT SOI (AND SOR) - LOCAL VERTICAL
#      COORDINATES
#
# SUBROUTINES USED
#
#  AVFLAGA
#  AVFLAGP
#  VNDSPLY
#  BANKCALL
#  GOFLASHR
#  GOTOPOOH
#  BLANKET
#  ENDOFJOB
#  PREC/TT
#  SELECTMU
#  INTRPVP
#  MAINRTNE

    BANK  04
    SETLOC  STBLEORB
    BANK

    EBANK=  SUBEXIT
    COUNT*  $$/P3879

P38    TC  AVFLAGA         # THIS VEHICLE ACTIVE
    TC      +2
P78    TC  AVFLAGP         # OTHER VEHICLE ACTIVE
    TC      P20FLGON        # SET UPDATFLG, TRACKFLG
    CAF  V06N33SR  # DISPLAY TIG
    TC  VNDSPLY
    CAF  V06N55SR  # DISPLAY CENTANG
    TCR  BANKCALL
    CADR  GOFLASHR
    TCF  GOTOPOOH  # TERMINATE
    TCF  +5    # PROCEED
    TCF  -5    # RECYCLE
    CAF  THREE    # IMMEDIATE RETURN - BLANK R1, R2
    TCR  BLANKET
    TCF  ENDOFJOB
    CAF  FIVE
    TS  OPTION1
    CAF  ONE
    TS  OPTION2    # OPTION CODE IS SET TO 1
# Page 527
    CAF  V04N06SR  # DISPLAY OPTION CODE - 1 = SOI, 2 = SOR
    TCR  BANKCALL
    CADR  GOFLASHR
    TCF  GOTOPOOH  # TERMINATE
    TCF  +5    # PROCEED
    TCF  -5    # RECYCLE
    CAF  BIT3    # IMMEDIATE RETURN - BLANK R3
    TCR  BLANKET
    TCF  ENDOFJOB
    TC  INTPRET
    SSP
            NN
            2
    SLOAD   SR1
      OPTION2
    BHIZ  DLOAD
      OPTN1
      TINT
    STORE  TINTSOI    # STORE FOR SOR PHASE
    CLRGO
      OPTNSW    # OPTNSW; ON = SOI, OFF = SOR
      JUNCTN1
OPTN1    SET  CLEAR    # SOI
      OPTNSW
      UPDATFLG
    CALL
      PREC/TT
    SET  DAD
      UPDATFLG
      TIG
    STORE  TINT    # TI = TIG + TF
    STORE  DSPTEM1    # FOR DISPLAY
    EXIT
    CAF  V06N57SR  # DISPLAY DELTA R
    TCR  BANKCALL
    CADR  GOFLASHR
    TCF  GOTOPOOH  # TERMINATE
    TCF  +5    # PROCEED
    TCF  -5    # RECYCLE
    CAF  SIX    # IMMEDIATE RETURN - BLANK R2, R3
    TCR  BLANKET
    TCF  ENDOFJOB
    CAF  V06N34SR  # DISPLAY TIME OF INTERCEPT
    TC  VNDSPLY
    TC  INTPRET
JUNCTN1    CLEAR  CALL
      P39/79SW
      SELECTMU  # SELECT MU, CLEAR FINALFLG, GO TO VN1645
RECYCLE    CALL
      PREC/TT
# Page 528
    BOFF  DLOAD
      OPTNSW
      OPTN2
      TINT
    STCALL  TDEC1    # PRECISION UPDATE PASSIVE VEHICLE TO
      INTRPVP    #  INTERCEPT TIME
    VLOAD  UNIT
      RATT    # RP/(RP)
    PDVL  VXV
      VATT
    ABVAL  NORM    # (VP X RP/(RP))
      X1
    PDDL  DDV
      DELTAR
    SL*      # DELTA R / (VP X RP/RP)
      0 -7,1
    STCALL  DELTTIME  # DELTA T = (RP) DELTA R / (VP X RP)
      JUNCTN2
OPTN2    DLOAD  DAD
      TINTSOI
      T
    STORE  TINT    # TI = TI + TF
JUNCTN2    DLOAD  DSU
      TINT
      DELTTIME
    STORE  TARGTIME  # TT = TI - DELTA T

# .... MAINRTNE ....
# SUBROUTINES USED
#
#  S3435.25
#  PERIAPO1
#  SHIFTR1
#  VNDSPLY
#  BANKCALL
#  GOFLASH
#  GOTOPOOH
#  VN1645

MAINRTNE  STCALL  TDEC1    # PRECISION UPDATE PASSIVE VEHICLE TO
      INTRPVP    #  TARGET TIME
    DLOAD
      TIG
    STORE  INTIME
    SSP  VLOAD
      SUBEXIT
      TEST3979
      RATT
    CALL
      S3435.25
TEST3979  BOFF  BON
# Page 529
      P39/79SW
      MAINRTN1
      FINALFLG
      P39P79
    SET
      UPDATFLG
P39P79    EXIT
    TC  DSPLY81    # FOR P39 AND P79
MAINRTN1  VLOAD  ABVAL
      DELVEET3
    STOVL  DELVTPI    # DELTA V
      VPASS4
    VSU  ABVAL
      VTPRIME
    STOVL  DELVTPF    # DELTA V (FINAL) = V'T - VT
      RACT3
    PDVL  CALL
      VIPRIME
      PERIAPO1  # GET PERIGEE ALTITUDE
    CALL
      SHIFTR1
    STORE  POSTTPI
    BON  SET
      FINALFLG
      DSPLY58
      UPDATFLG
DSPLY58    EXIT
    CAF  V06N58SR  # DISPLAY HP, DELTA V, DELTA V (FINAL)
    TC  VNDSPLY
DSPLY81    CAF  V06N81SR  # DISPLAY DELTA V (LV)
    TC  VNDSPLY
    TC  INTPRET
    CLEAR  VLOAD
      XDELVFLG
      DELVEET3
    STCALL  DELVSIN
      VN1645    # DISPLAY TRKMKCNT, TTOGO, +MGA
    BON  GOTO
      P39/79SW
      P39/P79B
      RECYCLE

# STABLE ORBIT MIDCOURSE PROGRAM (P39 AND P79)
#
# MOD NO -1    LOG SECTION - STABLE ORBIT - P38-P39
# MOD BY RUDNICKI, S  DATE 25JAN68
#
# FUNCTIONAL DESCRIPTION
#
#  P39 AND P79 CALCULATE THE REQUIRED DELTA V AND OTHER INITIAL
#  CONDITIONS REQUIRED BY THE AGC TO MAKE A MIDCOURSE CORRECTION
# Page 530
#  MANEUVER AFTER COMPLETING THE SOI MANEUVER BUT BEFORE MAKING
#  THE SOR MANEUVER
#
# CALLING SEQUENCE
#
#  ASTRONAUT REQUEST THRU DSKY
#
#  V37E39E    IF THIS VEHICLE IS ACTIVE VEHICLE
#  V37E79E    IF OTHER VEHICLE IS ACTIVE VEHICLE
#
# INPUT
#
#  (1)  TPASS4  TIME OF INTERCEPT - SAVED FROM P38/P78
#  (2)  TARGTIME  TIME THAT PASSIVE VEHICLE IS AT INTERCEPT POINT -
#      SAVED FROM P38/P78
#
# OUTPUT
#
#  (1)  TRKMKCNT  NUMBER OF MARKS
#  (2)  TTOGO  TIME TO GO
#  (3)  +MGA  MIDDLE GIMBAL ANGLE
#  (4)  DELVLVC  DELTA VELOCITY AT MID - LOCAL VERTICAL COORDINATES
#
# SUBROUTINES USED
#
#  AVFLAGA
#  AVFLAGP
#  LOADTIME
#  SELECTMU
#  PRECSET
#  S34/35.1
#  MAINRTNE

P39    TC  AVFLAGA    # THIS VEHICLE ACTIVE
    EXTEND
    DCA  ATIGINC
    TC  P39/P79A
P79    TC  AVFLAGP    # OTHER VEHICLE ACTIVE
    EXTEND
    DCA  PTIGINC
P39/P79A  DXCH  KT    # TIME TO PREPARE FOR BURN
    TC  P20FLGON  # SET UPDATFLG, TRACKFLG
    TC  INTPRET
    SET  CALL
      P39/79SW
      SELECTMU  # SELECT MU, CLEAR FINALFLG, GO TO VN1645
P39/P79B  RTB  DAD
      LOADTIME
      KT
    STORE  TIG    # TIG = T (PRESENT) + PREPARATION TIME
# Page531
    STCALL  TDEC1    # PRECISION UPDATE ACTIVE AND PASSIVE
      PRECSET    #  VEHICLES TO TIG
    CALL
      S34/35.1  # GET UNIT NORMAL
    DLOAD  GOTO
      TARGTIME
      MAINRTNE  # CALCULATE DELTA V AND DELTA V (LV)

# .... PREC/TT ....
# SUBROUTINES USED
#
#  PRECSET
#  TIMETHET
#  S34/35.1

PREC/TT    STQ  DLOAD
      RTRN
      TIG
    STCALL  TDEC1    # PRECISION UPDATE ACTIVE AND PASSIVE
      PRECSET    #  VEHICLES TO TIG
    VLOAD  VSR*
      RPASS3
      0,2
    STODL  RVEC
      CENTANG
    PUSH  COS
    STODL  CSTH
    SIN  SET
      RVSW
    STOVL  SNTH
      VPASS3
    VSR*
      0,2
    STCALL  VVEC    # GET TRANSFER TIME BASED ON CENTANG OF
      TIMETHET  #  PASSIVE VEHICLE
    CALL
      S34/35.1  # GET UNIT NORMAL
    DLOAD  GOTO
      T
      RTRN
# .... INTRPVP ....
# SUBROUTINES USED
#
#  CSMPREC
#  LEMPREC

INTRPVP    STQ  BOFF    # PRECISION UPDATE PASSIVE VEHICLE TO
      RTRN    #  TDEC1
      AVFLAG
      OTHERV
    CALL
# Page 532
      CSMPREC
    GOTO
      RTRN
OTHERV    CALL
      LEMPREC
    GOTO
      RTRN
# .... VNDSPLY ....
# SUBROUTINES USED
#
#  BANKCALL
#  GOFLASH
#  GOTOPOOH

VNDSPLY    EXTEND      # FLASH DISPLAY
    QXCH  RTRN
    TS  VERBNOUN
    CA  VERBNOUN
    TCR  BANKCALL
    CADR  GOFLASH
    TCF  GOTOPOOH  # TERMINATE
    TC  RTRN    # PROCEED
    TCF  -5    # RECYCLE
V06N33SR  VN  0633
V06N55SR  VN  0655
V04N06SR  VN  0406
V06N57SR  VN  0657
V06N34SR  VN  0634
V06N58SR  VN  0658
V06N81SR  VN  0681

# *** END OF COMEKISS.020 ***