Source Code
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These source-code files are part of a reconstructed copy of Luminary 69/2,
the flown, final release of the Apollo 10 Lunar Module (LM) Apollo Guidance Computer (AGC) software.
The reconstruction is based on the source code of Luminary 69 — i.e., the
initial, unflown version, "revision 0" — of which
a contemporary listing was available. The code was then updated by incorporating the
differences between Luminary 69 and Luminary 69/2, known from other contemporary
documentation. The only such difference is the implementation in
Luminary 69/2 of the "R-2 Lunar Potential Model", the source code for which was taken
from program Luminary 99/1 (Apollo 11 LM), of which a contemporary listing was also available.
Finally, the now-reconstructed Luminary 69/2 was then validated by assembling it to
executable form and verifying that its memory banks had the correct checksums,
known from still other contemporary documentation.
Note that page numbers in the reconstructed code match those in the original Luminary 69
program listing, or in the ORBITAL INTEGRATION log section, in Luminary 99/1. Page numbers
would certainly differ somewhat in a contemporary Luminary 69/2 listing.
Moreover, annotations that were not present in the contemporary source code have been added
to the reconstructed code to justify each change in Luminary 69/2 relative to
Luminary 69. Here's a guide to the Apollo documentation referenced in those annotations:
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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034501,000002: ## Copyright: Public domain.
034502,000003: ## Filename: THE_LUNAR_LANDING.agc
034503,000004: ## Purpose: A section of LUM69 revision 2.
034504,000005: ## It is part of the reconstructed source code for the flown
034505,000006: ## version of the flight software for the Lunar Module's (LM)
034506,000007: ## Apollo Guidance Computer (AGC) for Apollo 10. The code has
034507,000008: ## been recreated from a copy of Luminary revsion 069, using
034508,000009: ## changes present in Luminary 099 which were described in
034509,000010: ## Luminary memos 75 and 78. The code has been adapted such
034510,000011: ## that the resulting bugger words exactly match those specified
034511,000012: ## for LUM69 revision 2 in NASA drawing 2021152B, which gives
034512,000013: ## relatively high confidence that the reconstruction is correct.
034513,000014: ## Reference: pp. 789-796
034514,000015: ## Assembler: yaYUL
034515,000016: ## Contact: Ron Burkey <info@sandroid.org>.
034516,000017: ## Website: www.ibiblio.org/apollo/index.html
034517,000018: ## Mod history: 2019-07-27 MAS Created from Luminary 69.
034518,000019:
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Page 789
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034520,000021: 32,2772 BANK 32
034521,000022: 32,2000 SETLOC F2DPS*32
034522,000023: 32,2000 BANK
034523,000024:
034524,000025: 32,2772 E7,1617 EBANK= E2DPS
034525,000026:
034526,000027: # ****************************************
034527,000028: # P63: THE LUNAR LANDING, BRAKING PHASE
034528,000029: # ****************************************
034529,000030:
034530,000031: 32,2772 COUNT* $$/P63
034531,000032:
034532,000033: 32,2772 05353 P63LM TC PHASCHNG
034533,000034: 32,2773 04024 OCT 04024
034534,000035:
034535,000036: 32,2774 04616 TC BANKCALL # DO IMU STATUS CHECK ROUTINE R02
034536,000037: 32,2775 11175 CADR R02BOTH
034537,000038:
034538,000039: 32,2776 33246 CAF P63ADRES # INITIALIZE WHICH FOR BURNBABY
034539,000040: 32,2777 55453 TS WHICH
034540,000041:
034541,000042: 32,3000 32010 CAF DPSTHRSH # INITIALIZE DVMON
034542,000043: 32,3001 55251 TS DVTHRUSH
034543,000044: 32,3002 34751 CAF FOUR
034544,000045: 32,3003 55513 TS DVCNTR
034545,000046:
034546,000047: 32,3004 44753 CS ONE # INITIALIZE WCHPHASE AND FLPASSO
034547,000048: 32,3005 22007 ZL # FOR IGNITION ALGORITHM
034548,000049: 32,3006 53621 DXCH WCHPHASE
034549,000050:
034550,000051:
034551,000052: 32,3007 44736 CS BIT14
034552,000053: 32,3010 00006 EXTEND
034553,000054: 32,3011 03012 WAND CHAN12 # REMOVE TRACK-ENABLE DISCRETE.
034554,000055:
034555,000056: 32,3012 06036 FLAGORGY TC INTPRET # DIONYSIAN FLAG WAVING
034556,000057: 32,3013 43014 CLEAR CLEAR
034557,000058: 32,3014 02663 NOTHROTL
034558,000059: 32,3015 03271 REDFLAG
034559,000060: 32,3016 43014 CLEAR SET
034560,000061: 32,3017 05660 LRBYPASS
034561,000062: 32,3020 03067 MUNFLAG
034562,000063: 32,3021 43014 CLEAR CLEAR
034563,000064: 32,3022 00266 P25FLAG # TERMINATE P25 IF IT IS RUNNING.
034564,000065: 32,3023 00270 RNDVZFLG # TERMINATE P20 IF IT IS RUNNING
034565,000066:
034566,000067: # ****************************************
034567,000068:
034568,000069: 32,3024 77201 IGNALG SETPD VLOAD # FIRST SET UP INPUTS FOR RP-TO-R:-
034569,000070: 32,3025 00001 0 # AT 0D LANDING SITE IN MOON FIXED FRAME
034570,000071: 32,3026 02023 RLS # AT 6D ESTIMATED TIME OF LANDING
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Page 790
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034572,000073: 32,3027 41525 PDDL PUSH # MPAC NON-ZERO TO INDICATE LUNAR CASE
034573,000074: 32,3030 02401 TLAND
034574,000075: 32,3031 37623 STCALL TPIP # ALSO SET TPIP FOR FIRST GUIDANCE PASS
034575,000076: 32,3032 51504 RP-TO-R
034576,000077: 32,3033 64312 VSL4 MXV
034577,000078: 32,3034 01734 REFSMMAT
034578,000079: 32,3035 37633 STCALL LAND
034579,000080: 32,3036 60264 GUIDINIT # GUIDINIT INITIALIZES WM AND /LAND/
034580,000081: 32,3037 45345 DLOAD DSU
034581,000082: 32,3040 02401 TLAND
034582,000083: 32,3041 25254 GUIDDURN
034583,000084: 32,3042 34041 STCALL TDEC1 # INTEGRATE STATE FORWARD TO THAT TIME
034584,000085: 32,3043 27057 LEMPREC
034585,000086: 32,3044 77331 SSP VLOAD
034586,000087: 32,3045 03645 NIGNLOOP
034587,000088: 32,3046 00050 40D
034588,000089: 32,3047 06422 UNITX
034589,000090: 32,3050 26510 STOVL CG
034590,000091: 32,3051 06420 UNITY
034591,000092: 32,3052 26516 STOVL CG +6
034592,000093: 32,3053 06416 UNITZ
034593,000094: 32,3054 16524 STODL CG +14
034594,000095: 32,3055 25252 99999CON
034595,000096: 32,3056 27663 STOVL DELTAH # INITIALIZE DELTAH FOR V16N68 DISPLAY
034596,000097: 32,3057 06424 ZEROVECS
034597,000098: 32,3060 17252 STODL UNFC/2 # INITIALIZE TRIM VELOCITY CORRECTION TERM
034598,000099: 32,3061 06424 HI6ZEROS
034599,000100: 32,3062 03641 STORE TTF/8
034600,000101:
034601,000102: 32,3063 77745 IGNALOOP DLOAD
034602,000103: 32,3064 00015 TAT
034603,000104: 32,3065 27557 STOVL PIPTIME1
034604,000105: 32,3066 00017 RATT1
034605,000106: 32,3067 64312 VSL4 MXV
034606,000107: 32,3070 01734 REFSMMAT
034607,000108: 32,3071 37517 STCALL R
034608,000109: 32,3072 67162 MUNGRAV
034609,000110: 32,3073 35237 STCALL GDT/2
034610,000111: 32,3074 62514 ?GUIDSUB # WHICH DELIVERS N PASSES OF GUIDANCE
034611,000112:
034612,000113: # DDUMCALC IS PROGRAMMED AS FOLLOWS:-
034613,000114: # 2 -
034614,000115: # (RIGNZ - RGU )/16 + 16(RGU )KIGNY/B8 + (RGU - RIGNX)KIGNX/B4 + (ABVAL(VGU) - VIGN)KIGNV/B4
034615,000116: # 2 1 0
034616,000117: # DDUM = -------------------------------------------------------------------------------------------
034617,000118: # 10
034618,000119: # 2 (VGU - 16 VGU KIGNX/B4)
034619,000120: # 2 0
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Page 791
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034621,000122: # THE NUMERATOR IS SCALED IN METERS AT 2(28). THE DENOMINATOR IS A VELOCITY IN UNITS OF 2(10) M/CS.
034622,000123: # THE QUOTIENT IS THUS A TIME IN UNITS OF 2(18) CENTISECONDS. THE FINAL SHIFT RESCALES TO UNITS OF 2(28) CS.
034623,000124: # THERE IS NO DAMPING FACTOR. THE CONSTANTS KIGNX/B4, KIGNY/B8 AND KIGNV/B4 ARE ALL NEGATIVE IN SIGN.
034624,000125:
034625,000126: 32,3075 55644 DDUMCALC TS NIGNLOOP
034626,000127: 32,3076 06036 TC INTPRET
034627,000128: 32,3077 57345 DLOAD DMPR # FORM DENOMINATOR FIRST
034628,000129: 32,3100 03625 VGU
034629,000130: 32,3101 02471 KIGNX/B4
034630,000131: 32,3102 44232 SL4R BDSU
034631,000132: 32,3103 03631 VGU +4
034632,000133: 32,3104 45325 PDDL DSU
034633,000134: 32,3105 02467 RIGNZ
034634,000135: 32,3106 02550 RGU +4
034635,000136: 32,3107 65222 SR4R PDDL
034636,000137: 32,3110 02546 RGU +2
034637,000138: 32,3111 57316 DSQ DMPR
034638,000139: 32,3112 02473 KIGNY/B8
034639,000140: 32,3113 65232 SL4R PDDL
034640,000141: 32,3114 02544 RGU
034641,000142: 32,3115 57225 DSU DMPR
034642,000143: 32,3116 02465 RIGNX
034643,000144: 32,3117 02471 KIGNX/B4
034644,000145: 32,3120 51515 PDVL ABVAL
034645,000146: 32,3121 03625 VGU
034646,000147: 32,3122 57225 DSU DMPR
034647,000148: 32,3123 02463 VIGN
034648,000149: 32,3124 02475 KIGNV/B4
034649,000150: 32,3125 43215 DAD DAD
034650,000151: 32,3126 56215 DAD DDV
034651,000152: 32,3127 77661 SRR
034652,000153: 32,3130 21613 10D
034653,000154:
034654,000155: 32,3131 43206 PUSH DAD
034655,000156: 32,3132 03557 PIPTIME1
034656,000157: 32,3133 14041 STODL TDEC1 # STORE NEW GUESS FOR NEXT INTEGRATION
034657,000158: 32,3134 45246 ABS DSU
034658,000159: 32,3135 25256 DDUMCRIT
034659,000160: 32,3136 45040 BMN CALL
034660,000161: 32,3137 65156 DDUMGOOD
034661,000162: 32,3140 27412 INTSTALL
034662,000163: 32,3141 43014 SET SET
034663,000164: 32,3142 01473 INTYPFLG
034664,000165: 32,3143 00063 MOONFLAG
034665,000166: 32,3144 77745 DLOAD
034666,000167: 32,3145 03557 PIPTIME1
034667,000168: 32,3146 25517 STOVL TET # HOPEFULLY ?GUIDSUB DID NOT
034668,000169: 32,3147 00017 RATT1 # CLOBBER RATT1 AND VATT1
034669,000170: 32,3150 25535 STOVL RCV
034670,000171: 32,3151 00025 VATT1
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Page 792
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034672,000173: 32,3152 35543 STCALL VCV
034673,000174: 32,3153 27107 INTEGRVS
034674,000175: 32,3154 77650 GOTO
034675,000176: 32,3155 65063 IGNALOOP
034676,000177:
034677,000178: 32,3156 54335 DDUMGOOD SLOAD SR
034678,000179: 32,3157 03425 ZOOMTIME
034679,000180: 32,3160 20617 14D
034680,000181: 32,3161 77621 BDSU
034681,000182: 32,3162 00041 TDEC1
034682,000183: 32,3163 27440 STOVL TIG # COMPUTE DISTANCE LANDING SITE WILL BE
034683,000184: 32,3164 03525 V # OUT OF LM'S ORBITAL PLANE AT IGNITION:
034684,000185: 32,3165 53435 VXV UNIT # SIGN IS + IF LANDING SITE IS TO THE
034685,000186: 32,3166 03517 R # RIGHT, NORTH; - IF TO THE LEFT, SOUTH.
034686,000187: 32,3167 72441 DOT SL1
034687,000188: 32,3170 03633 LAND
034688,000189: 32,3171 26534 R60INIT STOVL OUTOFPLN # INITIALIZATION FOR CALCMANU
034689,000190: 32,3172 03252 UNFC/2
034690,000191: 32,3173 02536 STORE R60VSAVE # STORE UNFC/2 TEMPORARILY IN R60SAVE
034691,000192: 32,3174 77776 EXIT
034692,000193: # ****************************************
034693,000194:
034694,000195: 32,3175 05353 IGNALGRT TC PHASCHNG # PREVENT REPEATING IGNALG
034695,000196: 32,3176 04024 OCT 04024
034696,000197:
034697,000198: 32,3177 43247 ASTNCLOK CS ASTNDEX
034698,000199: 32,3200 04616 TC BANKCALL
034699,000200: 32,3201 74667 CADR STCLOK2
034700,000201: 32,3202 15155 TCF ENDOFJOB # RETURN IN NEW JOB AND IN EBANK FIVE
034701,000202:
034702,000203: 32,3203 06036 ASTNRET TC INTPRET
034703,000204: 32,3204 47131 SSP RTB # GO PICK UP DISPLAY AT END OF R51:
034704,000205: 32,3205 02747 QMAJ # "PROCEED" WILL DO A FINE ALIGNMENT
034705,000206: 32,3206 65210 FCADR P63SPOT2 # "ENTER" WILL RETURN TO P63SPOT2
034706,000207: 32,3207 30776 R51P63
034707,000208: 32,3210 53575 P63SPOT2 VLOAD UNIT # INITIALIZE KALCMANU FOR BURN ATTITUDE
034708,000209: 32,3211 02536 R60VSAVE
034709,000210: 32,3212 27767 STOVL POINTVSM
034710,000211: 32,3213 06422 UNITX
034711,000212: 32,3214 03761 STORE SCAXIS
034712,000213: 32,3215 77776 EXIT
034713,000214:
034714,000215: 32,3216 35016 CAF EBANK7
034715,000216: 32,3217 54003 TS EBANK
034716,000217:
034717,000218: 32,3220 00004 INHINT
034718,000219: 32,3221 04674 TC IBNKCALL
034719,000220: 32,3222 40142 CADR PFLITEDB
034720,000221: 32,3223 00003 RELINT
034721,000222:
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Page 793
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034723,000224: 32,3224 04616 TC BANKCALL
034724,000225: 32,3225 54101 CADR R60LEM
034725,000226:
034726,000227: 32,3226 05353 TC PHASCHNG # PREVENT RECALLING R60
034727,000228: 32,3227 04024 OCT 04024
034728,000229:
034729,000230: 32,3230 34746 P63SPOT3 CA BIT6 # IS THE LR ANTENNA IN POSITION 1 YET
034730,000231: 32,3231 00006 EXTEND
034731,000232: 32,3232 02033 RAND CHAN33
034732,000233: 32,3233 00006 EXTEND
034733,000234: 32,3234 13242 BZF P63SPOT4 # BRANCH IF ANTENNA ALREADY IN POSITION 1
034734,000235:
034735,000236: 32,3235 33250 CAF CODE500 # ASTRONAUT: PLEASE CRANK THE
034736,000237: 32,3236 04616 TC BANKCALL # SILLY THING AROUND
034737,000238: 32,3237 20476 CADR GOPERF1
034738,000239: 32,3240 16001 TCF GOTOPOOH # TERMINATE
034739,000240: 32,3241 13230 TCF P63SPOT3 # PROCEED SEE IF HE'S LYING
034740,000241:
034741,000242: 32,3242 04616 P63SPOT4 TC BANKCALL # ENTER INITIALIZE LANDING RADAR
034742,000243: 32,3243 67704 CADR SETPOS1
034743,000244:
034744,000245: 32,3244 04635 TC POSTJUMP # OFF TO SEE THE WIZARD ...
034745,000246: 32,3245 74124 CADR BURNBABY
034746,000247:
034747,000248: # ----------------------------------------
034748,000249:
034749,000250: # CONSTANTS FOR P63LM AND IGNALG
034750,000251:
034751,000252: 32,3246 02074 P63ADRES GENADR P63TABLE
034752,000253:
034753,000254: 32,3247 00027 ASTNDEX OCT 00027 # INDEX FOR CLOKTASK
034754,000255:
034755,000256: 32,3250 00500 CODE500 OCT 00500
034756,000257:
034757,000258: 32,3251 00035 30373 99999CON 2DEC 30479.7 B-24
034758,000259:
034759,000260: 32,3253 00003 37214 GUIDDURN 2DEC +65164 B-28
034760,000261: 32,3255 00000 00010 DDUMCRIT 2DEC +8 B-28 # CRITERION FOR IGNALG CONVERGENCE
034761,000262:
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Page 794
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034763,000264: # ----------------------------------------
034764,000265:
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Page 795
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034766,000267: # ****************************************
034767,000268: # P68: LANDING CONFIRMATION
034768,000269: # ****************************************
034769,000270:
034770,000271: 31,2172 BANK 31
034771,000272: 31,2000 SETLOC F2DPS*31
034772,000273: 31,2000 BANK
034773,000274:
034774,000275: 31,2172 COUNT* $$/P6567
034775,000276:
034776,000277: 31,2172 05353 LANDJUNK TC PHASCHNG
034777,000278: 31,2173 04024 OCT 04024
034778,000279:
034779,000280: 31,2174 00004 INHINT
034780,000281: 31,2175 04616 TC BANKCALL # ZERO ATTITUDE ERROR
034781,000282: 31,2176 40153 CADR ZATTEROR
034782,000283:
034783,000284: 31,2177 04616 TC BANKCALL # SET 5 DEGREE DEADBAND
034784,000285: 31,2200 40127 CADR SETMAXDB
034785,000286:
034786,000287: 31,2201 06036 TC INTPRET # TO INTERPRETIVE AS TIME IS NOT CRITICAL
034787,000288: 31,2202 43014 SET CLEAR
034788,000289: 31,2203 04067 SURFFLAG
034789,000290: 31,2204 04666 LETABORT
034790,000291: 31,2205 43014 SET CLEAR
034791,000292: 31,2206 05062 APSFLAG
034792,000293: 31,2207 03664 SWANDISP
034793,000294: 31,2210 77214 SET VLOAD
034794,000295: 31,2211 05460 LRBYPASS
034795,000296: 31,2212 01221 RN
034796,000297: 31,2213 16032 STODL ALPHAV
034797,000298: 31,2214 01235 PIPTIME
034798,000299: 31,2215 45014 SET CALL
034799,000300: 31,2216 01463 LUNAFLAG
034800,000301: 31,2217 26351 LAT-LONG
034801,000302: 31,2220 77201 SETPD VLOAD # COMPUTE RLS AND STORE IT AWAY
034802,000303: 31,2221 00001 0
034803,000304: 31,2222 01221 RN
034804,000305: 31,2223 65352 VSL2 PDDL
034805,000306: 31,2224 01235 PIPTIME
034806,000307: 31,2225 45006 PUSH CALL
034807,000308: 31,2226 51531 R-TO-RP
034808,000309: 31,2227 02023 STORE RLS
034809,000310: 31,2230 77776 EXIT
034810,000311: 31,2231 32246 CAF V06N43* # ASTRONAUT: NOW LOOK WHERE YOU ENDED UP
034811,000312: 31,2232 04616 TC BANKCALL
034812,000313: 31,2233 20351 CADR GOFLASH
034813,000314: 31,2234 16001 TCF GOTOPOOH # TERMINATE
034814,000315: 31,2235 12237 TCF +2 # PROCEED
034815,000316: 31,2236 12231 TCF -5 # RECYCLE
034816,000317:
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Page 796
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034818,000319: 31,2237 06036 TC INTPRET
034819,000320: 31,2240 77775 VLOAD # INITIALIZE GSAV AND (USING REFMF)
034820,000321: 31,2241 06422 UNITX # YNBSAV, ZNBSAV AND ATTFLAG FOR P57
034821,000322: 31,2242 36235 STCALL GSAV
034822,000323: 31,2243 33470 REFMF
034823,000324: 31,2244 77776 EXIT
034824,000325:
034825,000326: 31,2245 16001 TCF GOTOPOOH # ASTRONAUT: PLEASE SELECT P57
034826,000327:
034827,000328: 31,2246 01453 V06N43* VN 0643
034828,000329:
End of include-file THE_LUNAR_LANDING.agc. Parent file is MAIN.agc