Source Code
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These source-code files are part of a reconstructed copy of LUM69 Revision 2, the
flown Apollo 10 Lunar Module (LM) Apollo Guidance Computer (AGC) software.
The reconstruction began with source code of Luminary 69 revision 0 previously
transcribed from a digitized copy of that program. The code was then updated
by back-porting the R-2 lunar potential model from previously-transcribed source
code of Luminary 99. These required changes were described in the original
Luminary memos 75 and 78. The reconstructed code was verified by
matching memory-bank checksums to those listed in drawing 2021152G. Note that
page numbers in the reconstructed code match those on the Luminary 069 printout,
although the added code would likely have changed page numbers for a real LUM69
Revision 2 listing.
Comments from the original source code are prefixed with a single '#' symbol,
whereas comments added later are prefixed by "##" or "###". Report any errors
noted by creating an
issue report at the Virtual AGC
project's GitHub repository.
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048591,000002: ## Copyright: Public domain.
048592,000003: ## Filename: PLANETARY_INERTIAL_ORIENTATION.agc
048593,000004: ## Purpose: A section of LUM69 revision 2.
048594,000005: ## It is part of the reconstructed source code for the flown
048595,000006: ## version of the flight software for the Lunar Module's (LM)
048596,000007: ## Apollo Guidance Computer (AGC) for Apollo 10. The code has
048597,000008: ## been recreated from a copy of Luminary revsion 069, using
048598,000009: ## changes present in Luminary 099 which were described in
048599,000010: ## Luminary memos 75 and 78. The code has been adapted such
048600,000011: ## that the resulting bugger words exactly match those specified
048601,000012: ## for LUM69 revision 2 in NASA drawing 2021152B, which gives
048602,000013: ## relatively high confidence that the reconstruction is correct.
048603,000014: ## Reference: pp. 1135-1143
048604,000015: ## Assembler: yaYUL
048605,000016: ## Contact: Ron Burkey <info@sandroid.org>.
048606,000017: ## Website: www.ibiblio.org/apollo/index.html
048607,000018: ## Mod history: 2019-07-27 MAS Created from Luminary 69.
048608,000019:
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Page 1135
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048610,000021: # ..... RP-TO-R SUBROUTINE .....
048611,000022: # SUBROUTINE TO CONVERT RP (VECTOR IN PLANETARY COORDINATE SYSTEM, EITHER
048612,000023: # EARTH-FIXED OR MOON-FIXED) TO R (SAME VECTOR IN THE BASIC REF. SYSTEM)
048613,000024:
048614,000025: # R = MT(T)*(RP + LP X RP) MT = M MATRIX TRANSPOSE
048615,000026:
048616,000027: # CALLING SEQUENCE
048617,000028: # L CALL
048618,000029: # L+1 RP-TO-R
048619,000030:
048620,000031: # SUBROUTINES USED
048621,000032: # EARTHMX,MOONMX,EARTHL
048622,000033:
048623,000034: # ITEMS AVAILABLE FROM LAUNCH DATA
048624,000035: # 504LM = THE LIBRATION VECTOR L OF THE MOON AT TIME TIMSUBL,EXPRESSED
048625,000036: # IN THE MOON-FIXED COORD. SYSTEM RADIANS B0
048626,000037:
048627,000038: # ITEMS NECESSARY FOR SUBR. USED (SEE DESCRIPTION OF SUBR.)
048628,000039:
048629,000040: # INPUT
048630,000041: # MPAC= 0 FOR EARTH, NON-ZERO FOR MOON
048631,000042: # 0-5D= RP VECTOR
048632,000043: # 6-7D= TIME
048633,000044:
048634,000045: # OUTPUT
048635,000046: # MPAC = R VECTOR METERS B-29 FOR EARTH, B-27 FOR MOON
048636,000047:
048637,000048: 24,2000 SETLOC PLANTIN
048638,000049: 24,2000 BANK
048639,000050:
048640,000051: 24,3504 COUNT* $$/LUROT
048641,000052:
048642,000053: 24,3504 46020 RP-TO-R STQ BHIZ
048643,000054: 24,3505 00050 RPREXIT
048644,000055: 24,3506 51521 RPTORA
048645,000056: 24,3507 77624 CALL # COMPUTE M MATRIX FOR MOON
048646,000057: 24,3510 51561 MOONMX # LP=LM FOR MOON RADIANS B0
048647,000058: 24,3511 77775 VLOAD
048648,000059: 24,3512 02013 504LM
048649,000060: 24,3513 53235 RPTORB VXV VAD
048650,000061: 24,3514 00001 504RPR
048651,000062: 24,3515 00001 504RPR
048652,000063: 24,3516 52105 VXM GOTO
048653,000064: 24,3517 00025 MMATRIX # MPAC=R=MT(T)*(RP+LPXRP)
048654,000065: 24,3520 51547 RPRPXXXX # RESET PUSHLOC TO 0 BEFORE EXITING
048655,000066: 24,3521 77624 RPTORA CALL # EARTH COMPUTATIONS
048656,000067: 24,3522 55657 EARTHMX # M MATRIX B-1
048657,000068: 24,3523 77624 CALL
048658,000069: 24,3524 55711 EARTHL # L VECTOR RADIANS B0
048659,000070: 24,3525 76521 MXV VSL1 # LP=M(T)*L RAD B-0
048660,000071: 24,3526 00025 MMATRIX
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Page 1136
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048662,000073: 24,3527 77650 GOTO
048663,000074: 24,3530 51513 RPTORB
048664,000075:
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Page 1137
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048666,000077: # ..... R-TO-RP SUBROUTINE .....
048667,000078: # SUBROUTINE TO CONVERT R (VECTOR IN REFERENCE COORD. SYSTEM) TO RP
048668,000079: # (VECTOR IN PLANETARY COORD SYSTEM) EITHER EARTH-FIXED OR MOON-FIXED
048669,000080:
048670,000081: # RP = M(T)*(R - L X R)
048671,000082:
048672,000083: # CALLING SEQUENCE
048673,000084: # L CALL
048674,000085: # L+1 R-TO-RP
048675,000086:
048676,000087: # SUBROUTINES USED
048677,000088: # EARTHMX,MOONMX,EARTHL
048678,000089:
048679,000090: # INPUT
048680,000091: # MPAC= 0 FOR EARTH,NON-ZERO FOR MOON
048681,000092: # 0-5D= R VECTOR
048682,000093: # 6-7D= TIME
048683,000094:
048684,000095: # ITEMS AVAILABLE FROM LAUNCH DATA
048685,000096: # 504LM = THE LIBRATION VECTOR L OF THE MOON AT TIME TIMSUBL,EXPRESSED
048686,000097: # IN THE MOON-FIXED COORD. SYSTEM RADIANS B0
048687,000098:
048688,000099: # ITEMS NECESSARY FOR SUBROUTINES USED (SEE DESCRIPTION OF SUBR.)
048689,000100:
048690,000101: # OUTPUT
048691,000102: # MPAC = RP VECTOR METERS B-29 FOR EARTH, B-27 FOR MOON
048692,000103:
048693,000104: 24,3531 46020 R-TO-RP STQ BHIZ
048694,000105: 24,3532 00050 RPREXIT
048695,000106: 24,3533 51553 RTORPA
048696,000107: 24,3534 77624 CALL
048697,000108: 24,3535 51561 MOONMX
048698,000109: 24,3536 61375 VLOAD VXM
048699,000110: 24,3537 02013 504LM # LP=LM
048700,000111: 24,3540 00025 MMATRIX
048701,000112: 24,3541 77772 VSL1 # L=MT(T)*LP RADIANS B0
048702,000113: 24,3542 51235 RTORPB VXV BVSU
048703,000114: 24,3543 00001 504RPR
048704,000115: 24,3544 00001 504RPR
048705,000116: 24,3545 77721 MXV # M(T)*(R-LXR) B-2
048706,000117: 24,3546 00025 MMATRIX
048707,000118: 24,3547 40372 RPRPXXXX VSL1 SETPD
048708,000119: 24,3550 00001 0D
048709,000120: 24,3551 77650 GOTO
048710,000121: 24,3552 00050 RPREXIT
048711,000122: 24,3553 77624 RTORPA CALL # EARTH COMPUTATIONS
048712,000123: 24,3554 55657 EARTHMX
048713,000124: 24,3555 77624 CALL
048714,000125: 24,3556 55711 EARTHL
048715,000126: 24,3557 77650 GOTO # MPAC=L=(-AX,-AY,0) RAD B-0
048716,000127: 24,3560 51542 RTORPB
048717,000128:
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Page 1138
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048719,000130: # ..... MOONMX SUBROUTINE .....
048720,000131: # SUBROUTINE TO COMPUTE THE TRANSFORMATION MATRIX M FOR THE MOON
048721,000132:
048722,000133: # CALLING SEQUENCE
048723,000134: # L CALL
048724,000135: # L+1 MOONMX
048725,000136:
048726,000137: # SUBROUTINES USED
048727,000138: # NEWANGLE
048728,000139:
048729,000140: # INPUT
048730,000141: # 6-7D= TIME
048731,000142:
048732,000143: # ITEMS AVAILABLE FROM LAUNCH DATA
048733,000144: # BSUBO,BDOT
048734,000145: # TIMSUBO,NODIO,NODDOT,FSUBO,FDOT
048735,000146: # COSI= COS(I) B-1
048736,000147: # SINI= SIN(I) B-1
048737,000148: # I IS THE ANGLE BETWEEN THE MEAN LUNAR EQUATORIAL PLANE AND THE
048738,000149: # PLANE OF THE ECLIPTIC (1 DEGREE 32.1 MINUTES)
048739,000150:
048740,000151: # OUTPUT
048741,000152: # MMATRIX= 3X3 M MATRIX B-1 (STORED IN VAC AREA)
048742,000153:
048743,000154: 24,3561 40220 MOONMX STQ SETPD
048744,000155: 24,3562 00051 EARTHMXX
048745,000156: 24,3563 00011 8D
048746,000157: 24,3564 77770 AXT,1 # B REQUIRES SL 0, SL 5 IN NEWANGLE
048747,000158: 24,3565 00005 5
048748,000159: 24,3566 65345 DLOAD PDDL # PD 10D 8-9D=BSUBO
048749,000160: 24,3567 10017 BSUBO # 10-11D=BDOT
048750,000161: 24,3570 10011 BDOT
048751,000162: 24,3571 45006 PUSH CALL # PD 12D
048752,000163: 24,3572 51706 NEWANGLE # EXIT WITH PD 8D AND MPAC= B REVS B0
048753,000164: 24,3573 71406 PUSH COS # PD 10D
048754,000165: 24,3574 14041 STODL COB # PD 8D COS(B) B-1
048755,000166: 24,3575 77756 SIN # SIN(B) B-1
048756,000167: 24,3576 14043 STODL SOB # SETUP INPUT FOR NEWANGLE
048757,000168: 24,3577 10015 FSUBO # 8-9D=FSUBO
048758,000169: 24,3600 41525 PDDL PUSH # PD 10D THEN 12D 10-11D=FDOT
048759,000170: 24,3601 10007 FDOT
048760,000171: 24,3602 45170 AXT,1 CALL # F REQUIRES SL 1, SL 6 IN NEWANGLE
048761,000172: 24,3603 00004 4
048762,000173: 24,3604 51706 NEWANGLE # EXIT WITH PD 8D AND MPAC= F REVS B0
048763,000174: 24,3605 14027 STODL AVECTR +2 # SAVE F TEMP
048764,000175: 24,3606 10013 NODIO # 8-9D=NODIO
048765,000176: 24,3607 41525 PDDL PUSH # PD 10D THEN 12D 10-11D=NODDOT
048766,000177: 24,3610 10005 NODDOT # MPAC=T
048767,000178: 24,3611 45170 AXT,1 CALL # NODE REQUIRES SL 0, SL 5 IN NEWANGLE
048768,000179: 24,3612 00005 5
048769,000180: 24,3613 51706 NEWANGLE # EXIT WITH PD 8D AND MPAC= NODI REVS B0
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Page 1139
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048771,000182: 24,3614 71406 PUSH COS # PD 10D 8-9D= NODI REVS B0
048772,000183: 24,3615 77606 PUSH # PD 12D 10-11D= COS(NODI) B-1
048773,000184: 24,3616 00025 STORE AVECTR
048774,000185: 24,3617 76405 DMP SL1R
048775,000186: 24,3620 00041 COB # COS(NODI) B-1
048776,000187: 24,3621 14035 STODL BVECTR +2 # PD 10D 20-25D=AVECTR= COB*SIN(NODI)
048777,000188: 24,3622 76405 DMP SL1R # SOB*SIN(NODI)
048778,000189: 24,3623 00043 SOB
048779,000190: 24,3624 14037 STODL BVECTR +4 # PD 8D
048780,000191: 24,3625 41556 SIN PUSH # PD 10D -SIN(NODI) B-1
048781,000192: 24,3626 77676 DCOMP # 26-31D=BVECTR= COB*COS(NODI)
048782,000193: 24,3627 14033 STODL BVECTR # PD 8D SOB*COS(NODI)
048783,000194: 24,3630 00027 AVECTR +2 # MOVE F FROM TEMP LOC. TO 504F
048784,000195: 24,3631 14007 STODL 504F
048785,000196: 24,3632 76405 DMP SL1R
048786,000197: 24,3633 00041 COB
048787,000198: 24,3634 14027 STODL AVECTR +2
048788,000199: 24,3635 00011 SINNODI # 8-9D=SIN(NODI) B-1
048789,000200: 24,3636 76405 DMP SL1R
048790,000201: 24,3637 00043 SOB
048791,000202: 24,3640 14031 STODL AVECTR +4 # 0
048792,000203: 24,3641 06424 HI6ZEROS # 8-13D= CVECTR= -SOB B-1
048793,000204: 24,3642 57525 PDDL DCOMP # PD 10D COB
048794,000205: 24,3643 00043 SOB
048795,000206: 24,3644 63325 PDDL PDVL # PD 12D THEN PD 14D
048796,000207: 24,3645 00041 COB
048797,000208: 24,3646 00033 BVECTR
048798,000209: 24,3647 63361 VXSC PDVL # PD 20D BVECTR*SINI B-2
048799,000210: 24,3650 10003 SINI
048800,000211: 24,3651 00011 CVECTR
048801,000212: 24,3652 53361 VXSC VAD # PD 14D CVECTR*COSI B-2
048802,000213: 24,3653 10001 COSI
048803,000214: 24,3654 77772 VSL1
048804,000215: 24,3655 24041 STOVL MMATRIX +12D # PD 8D M2=BVECTR*SINI+CVECTR*COSI B-1
048805,000216: 24,3656 63361 VXSC PDVL # PD 14D
048806,000217: 24,3657 10003 SINI # CVECTR*SINI B-2
048807,000218: 24,3660 00033 BVECTR
048808,000219: 24,3661 52361 VXSC VSU # PD 8D BVECTR*COSI B-2
048809,000220: 24,3662 10001 COSI
048810,000221: 24,3663 65372 VSL1 PDDL # PD 14D
048811,000222: 24,3664 00007 504F # 8-13D=DVECTR=BVECTR*COSI-CVECTR*SINI B-1
048812,000223: 24,3665 74346 COS VXSC
048813,000224: 24,3666 00011 DVECTR
048814,000225: 24,3667 73525 PDDL SIN # PD 20D 14-19D= DVECTR*COSF B-2
048815,000226: 24,3670 00007 504F
048816,000227: 24,3671 52361 VXSC VSU # PD 14D AVECTR*SINF B-2
048817,000228: 24,3672 00025 AVECTR
048818,000229: 24,3673 77772 VSL1
048819,000230: 24,3674 14033 STODL MMATRIX +6 # M1= AVECTR*SINF-DVECTR*COSF B-1
048820,000231: 24,3675 00007 504F
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Page 1140
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048822,000233: 24,3676 74356 SIN VXSC # PD 8D
048823,000234: 24,3677 71525 PDDL COS # PD 14D 8-13D=DVECTR*SINF B-2
048824,000235: 24,3700 00007 504F
048825,000236: 24,3701 53361 VXSC VAD # PD 8D AVECTR*COSF B-2
048826,000237: 24,3702 00025 AVECTR
048827,000238: 24,3703 57572 VSL1 VCOMP
048828,000239: 24,3704 34025 STCALL MMATRIX # M0= -(AVECTR*COSF+DVECTR*SINF) B-1
048829,000240: 24,3705 00051 EARTHMXX
048830,000241:
048831,000242: # COMPUTE X=X0+(XDOT)(T+T0)
048832,000243: # 8-9D= XO (REVS B-0), PUSHLOC SET AT 12D
048833,000244: # 10-11D=XDOT (REVS/CSEC) SCALED B+23 FOR WEARTH,B+28 FOR NODDOT AND BDOT
048834,000245: # AND B+27 FOR FDOT
048835,000246: # X1=DIFFERENCE IN 23 AND SCALING OF XDOT,=0 FOR WEARTH,5 FOR NODDOT AND
048836,000247: # BDOT AND 4 FOR FDOT
048837,000248: # 6-7D=T (CSEC B-28), TIMSUBO= (CSEC B-42 TRIPLE PREC.)
048838,000249:
048839,000250: 24,3706 54345 NEWANGLE DLOAD SR # ENTER PD 12D
048840,000251: 24,3707 00007 6D
048841,000252: 24,3710 20617 14D
048842,000253: 24,3711 72371 TAD TLOAD # CHANGE MODE TO TP
048843,000254: 24,3712 01707 TIMSUBO
048844,000255: 24,3713 00155 MPAC
048845,000256: 24,3714 14017 STODL TIMSUBM # T+T0 CSEC B-42
048846,000257: 24,3715 00020 TIMSUBM +1
048847,000258: 24,3716 77605 DMP # PD 10D MULT BY XDOT IN 10-11D
048848,000259: 24,3717 43257 SL* DAD # PD 8D ADD XO IN 8-9D AFTER SHIFTING
048849,000260: 24,3720 20206 5,1 # SUCH THAT SCALING IS B-0
048850,000261: 24,3721 67206 PUSH SLOAD # PD 10D SAVE PARTIAL (X0+XDOT*T) IN 8-9D
048851,000262: 24,3722 00017 TIMSUBM
048852,000263: 24,3723 41261 SL DMP
048853,000264: 24,3724 20212 9D
048854,000265: 24,3725 00013 10D # XDOT
048855,000266: 24,3726 43257 SL* DAD # PD 8D SHIFT SUCH THAT THIS PART OF X
048856,000267: 24,3727 20213 10D,1 # IS SCALED REVS/CSEC B-0
048857,000268: 24,3730 77600 BOV # TURN OFF OVERFLOW IF SET BY SHIFT
048858,000269: 24,3731 51732 +1 # INSTRUCTION BEFORE EXITING
048859,000270: 24,3732 77616 RVQ # MPAC=X= X0+(XDOT)(T+T0) REVS B0
048860,000271:
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Page 1141
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048862,000273: # ..... EARTHMX SUBROUTINE .....
048863,000274: # SUBROUTINE TO COMPUTE THE TRANSFORMATION MATRIX M FOR THE EARTH
048864,000275:
048865,000276: # CALLING SEQUENCE
048866,000277: # L CALL
048867,000278: # L+1 EARTHMX
048868,000279:
048869,000280: # SUBROUTINES USED
048870,000281: # NEWANGLE
048871,000282:
048872,000283: # INPUT
048873,000284: # INPUT AVAILABLE FROM LAUNCH DATA AZO REVS B-0
048874,000285: # TEPHEM CSEC B-42
048875,000286: # 6-7D= TIME CSEC B-28
048876,000287:
048877,000288: # OUTPUT
048878,000289: # MMATRIX= 3X3 M MATRIX B-1 (STORED IN VAC AREA)
048879,000290:
048880,000291: 26,3657 BANK 26
048881,000292: 26,2000 SETLOC PLANTIN1
048882,000293: 26,2000 BANK
048883,000294: 26,3657 COUNT* $$/LUROT
048884,000295:
048885,000296: 26,3657 40220 EARTHMX STQ SETPD # SET 8-9D=AZO
048886,000297: 26,3660 00051 EARTHMXX
048887,000298: 26,3661 00011 8D # 10-11D=WEARTH
048888,000299: 26,3662 77770 AXT,1 # FOR SL 5, AND SL 10 IN NEWANGLE
048889,000300: 26,3663 00000 0
048890,000301: 26,3664 65345 DLOAD PDDL # LEAVING PD SET AT 12D FOR NEWANGLE
048891,000302: 26,3665 01712 AZO
048892,000303: 26,3666 10021 WEARTH
048893,000304: 26,3667 45006 PUSH CALL
048894,000305: 26,3670 51706 NEWANGLE
048895,000306: 26,3671 41401 SETPD PUSH # 18-19D=504AZ
048896,000307: 26,3672 00023 18D # COS(AZ) SIN(AZ) 0
048897,000308: 26,3673 65346 COS PDDL # 20-37D= MMATRIX= -SIN(AZ) COS(AZ) 0 B-1
048898,000309: 26,3674 00023 504AZ # 0 0 1
048899,000310: 26,3675 65356 SIN PDDL
048900,000311: 26,3676 06424 HI6ZEROS
048901,000312: 26,3677 73525 PDDL SIN
048902,000313: 26,3700 00023 504AZ
048903,000314: 26,3701 65276 DCOMP PDDL
048904,000315: 26,3702 00023 504AZ
048905,000316: 26,3703 63346 COS PDVL
048906,000317: 26,3704 06424 HI6ZEROS
048907,000318: 26,3705 41525 PDDL PUSH
048908,000319: 26,3706 06422 HIDPHALF
048909,000320: 26,3707 77650 GOTO
048910,000321: 26,3710 00051 EARTHMXX
048911,000322:
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Page 1142
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048913,000324: # ..... EARTHL SUBROUTINE .....
048914,000325: # SUBROUTINE TO COMPUTE L VECTOR FOR EARTH
048915,000326:
048916,000327: # CALLING SEQUENCE
048917,000328: # L CALL
048918,000329: # L+1 EARTHL
048919,000330:
048920,000331: # INPUT
048921,000332: # AXO,AYO SET AT LAUNCH TIME WITH AYO IMMEDIATELY FOLLOWING AXO IN CORE
048922,000333:
048923,000334: # OUTPUT
048924,000335: # -AX
048925,000336: # MPAC= -AY RADIANS B-0
048926,000337: # 0
048927,000338:
048928,000339: 26,3711 57545 EARTHL DLOAD DCOMP
048929,000340: 26,3712 01716 AXO
048930,000341: 26,3713 14017 STODL 504LPL
048931,000342: 26,3714 01714 -AYO
048932,000343: 26,3715 14021 STODL 504LPL +2
048933,000344: 26,3716 06424 HI6ZEROS
048934,000345: 26,3717 24023 STOVL 504LPL +4
048935,000346: 26,3720 00017 504LPL
048936,000347: 26,3721 77616 RVQ
048937,000348:
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Page 1143
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048939,000350: # CONSTANTS AND ERASABLE ASSIGNMENTS
048940,000351:
048941,000352: 26,3722 11,2272 1B1 = DP1/2 # 1 SCALED B-1
048942,000353: 26,3722 0000050 RPREXIT = S1 # R-TO-RP AND RP-TO-R SUBR EXIT
048943,000354: 26,3722 0000051 EARTHMXX = S2 # EARTHMX,MOONMX SUBR. EXITS
048944,000355: 26,3722 504RPR = 0D # 6 REGS R OR RP VECTOR
048945,000356: 26,3722 SINNODI = 8D # 2 SIN(NODI)
048946,000357: 26,3722 DVECTR = 8D # 6 D VECTOR MOON
048947,000358: 26,3722 CVECTR = 8D # 6 C VECTR MOON
048948,000359: 26,3722 504AZ = 18D # 2 AZ
048949,000360: 26,3722 TIMSUBM = 14D # 3 TIME SUB M (MOON) T+T0 IN GETAZ
048950,000361: 26,3722 504LPL = 14D # 6 L OR LP VECTOR
048951,000362: 26,3722 AVECTR = 20D # 6 A VECTOR (MOON)
048952,000363: 26,3722 BVECTR = 26D # 6 B VECTOR (MOON)
048953,000364: 26,3722 MMATRIX = 20D # 18 M MATRIX
048954,000365: 26,3722 COB = 32D # 2 COS(B) B-1
048955,000366: 26,3722 SOB = 34D # 2 SIN(B) B-1
048956,000367: 26,3722 504F = 6D # 2 F(MOON)
048957,000368:
End of include-file PLANETARY_INERTIAL_ORIENTATION.agc. Parent file is MAIN.agc