Source Code
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These source code files are a reconstruction of Sundance, the Apollo 9 LM (Lunar Module) AGC
(Apollo Guidance Computer) flight software, created from binary dumps of original core rope
program modules, as follows:
Since only binary dumps (rather than listings) of Sundance are available as source material, all comments and labels are approximate. They have been taken from other AGC programs where possible, or, in some places, written from scratch to match what we believe would have been in the original listing. |
038318,000002: ## Copyright: Public domain.
038319,000003: ## Filename: LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc
038320,000004: ## Purpose: A section of a reconstructed, mixed version of Sundance
038321,000005: ## It is part of the reconstructed source code for the Lunar
038322,000006: ## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 9.
038323,000007: ## No original listings of this program are available;
038324,000008: ## instead, this file was created via disassembly of dumps
038325,000009: ## of various revisions of Sundance core rope modules.
038326,000010: ## Assembler: yaYUL
038327,000011: ## Contact: Ron Burkey <info@sandroid.org>.
038328,000012: ## Website: www.ibiblio.org/apollo/index.html
038329,000013: ## Mod history: 2020-06-17 MAS Created from Luminary 69.
038330,000014: ## 2021-05-30 ABS 2DEC* -> DEC for non extended address field.
038331,000015:
038332,000016: ## Sundance 302
038333,000017:
038334,000018: # NAME - LSPOS - LOCATE SUN AND MOON DATE - 25 OCT 67
038335,000019: # MOD NO.1
038336,000020: # MOD BY NEVILLE ASSEMBLY SUNDANCE
038337,000021:
038338,000022: # FUNCTIONAL DESCRIPTION
038339,000023:
038340,000024: # COMPUTES UNIT POSITION VECTOR OF THE SUN AND MOON IN THE BASIC REFERENCE SYSTEM. THE SUN VECTOR S IS
038341,000025: # LOCATED VIA TWO ANGLES. THE FIRST ANGLE(OBLIQUITY) IS THE ANGLE BETWEEN THE EARTH EQUATOR AND THE ECLIPTIC. THE
038342,000026: # SECOND ANGLE IS THE LONGITUDE OF THE SUN MEASURED IN THE ECLIPTIC.
038343,000027: # THE POSITION VECTOR OF THE SUN IS
038344,000028: # -
038345,000029: # S = (COS(LOS), COS(OBL)*SIN(LOS), SIN(OBL)*SIN(LOS)), WHERE
038346,000030:
038347,000031: # LOS = LOS +LOS *T-(C *SIN(2PI*T)/365.24 +C *COS(2PI*T)/365.24)
038348,000032: # 0 R 0 1
038349,000033: # LOS (RAD) IS THE LONGITUDE OF THE SUN FOR MIDNIGHT JUNE 30TH OF THE PARTICULAR YEAR.
038350,000034: # 0
038351,000035: # LOS (RAD/DAY) IS THE MEAN RATE FOR THE PARTICULAR YEAR.
038352,000036: # R
038353,000037:
038354,000038: # LOS AND LOS ARE STORED AS LOSC AND LOSR IN RATESP.
038355,000039: # 0 R
038356,000040: # COS(OBL) AND SIN(OBL) ARE STORED IN THE MATRIX KONMAT.
038357,000041: # T, TIME MEASURED IN DAYS (24 HOURS), IS STORED IN TIMEP.
038358,000042: # C AND C ARE FUDGE FACTORS TO MINIMIZE THE DEVIATION. THEY ARE STORED AS ONE CONSTANT (CMOD), SINCE
038359,000043: # 0 1 2 2 1/2
038360,000044: # C *SIN(X)+C *COS(X) CAN BE WRITTEN AS (C +C ) *SIN(X+PHI), WHERE PHI=ARCTAN(C /C ).
038361,000045: # 0 1 0 1 1 0
038362,000046:
038363,000047: # THE MOON IS LOCATED VIA FOUR ANGLES. THE FIRST IS THE OBLIQUITY. THE SECOND IS THE MEAN LONGITUDE OF THE MOON,
038364,000048: # MEASURED IN THE ECLIPTIC FROM THE MEAN EQUINOX TO THE MEAN ASCENDING NODE OF THE LUNAR ORBIT, AND THEN ALONG THE
038365,000049: # ORBIT. THE THIRD ANGLE IS THE ANGLE BETWEEN THE ECLIPTIC AND THE LUNAR ORBIT. THE FOURTH ANGLE IS THE LONGITUDE
038366,000050: # OF THE NODE OF THE MOON, MEASURED IN THE LUNAR ORBIT. LET THESE ANGLES BE OBL,LOM,IM, AND LON RESPECTIVELY.
038367,000051:
038368,000052: # THE SIMPLIFIED POSITION VECTOR OF THE MOON IS
038369,000053: # -
038370,000054: # M=(COS(LOM), COS(OBL)*SIN(LOM)-SIN(OBL)*SIN(IM)*SIN(LOM-LON), SIN(OBL)*SIN(LOM)+COS(OBL)*SIN(IM)*SIN(LOM-LON))
038371,000055:
038372,000056: # WHERE
038373,000057: # LOM=LOM +LOM *T-(A *SIN 2PI*T/27.5545+A *COS(2PI*T/27.5545)+B *SIN 2PI*T/32+B *COS(2PI*T/32)), AND
038374,000058: # 0 R 0 1 0 1
038375,000059: # LON=LON +LON
038376,000060: # 0 R
038377,000061: # A , A , B AND B ARE STORED AS AMOD AND BMOD (SEE DESCRIPTION OF CMOD, ABOVE). COS(OBL), SIN(OBL)*SIN(IM),
038378,000062: # 0 1 0 1
038379,000063: # SIN(OBL), AND COS(OBL)*SIN(IM) ARE STORED IN KONMAT AS K1, K2, K3 AND K4, RESPECTIVELY. LOM , LOM , LON , LON
038380,000064: # ARE STORED AS LOMO, LOMR, LONO, AND LONR IN RATESP. 0 R 0 R
038381,000065: # THE THREE PHIS ARE STORED AS AARG, BARG, AND CARG(SUN). ALL CONSTANTS ARE UPDATED BY YEAR.
038382,000066:
038383,000067: # CALLING SEQUENCE
038384,000068: # CALL LSPOS. RETURN IS VIA CPRET.
038385,000069:
038386,000070: # ALARMS OR ABORTS
038387,000071: # NONE
038388,000072:
038389,000073: # ERASABLE INITIALIZATION REQUIRED
038390,000074: # TEPHEM - TIME FROM MIDNIGHT 1 JULY PRECEDING THE LAUNCH TO THE TIME OF THE LAUNCH (WHEN THE AGC CLOCK WENT
038391,000075: # TO ZERO). TEPHEM IS TP WITH UNITS OF CENTI-SECONDS.
038392,000076:
038393,000077: # TIME2 AND TIME1 ARE IN MPAC AND MPAC +1 WHEN PROGRAM IS CALLED.
038394,000078:
038395,000079: # OUTPUT
038396,000080: # UNIT POSITIONAL VECTOR OF SUN IN VSUN. (SCALED B-1)
038397,000081: # UNIT POSITIONAL VECTOR OF MOON IN VMOON. (SCALED B-1)
038398,000082:
038399,000083: # SUBROUTINES USED
038400,000084: # NONE
038401,000085:
038402,000086: # DEBRIS
038403,000087: # CURRENT CORE SET, WORK AREA AND FREEFLAG
038404,000088:
038405,000089: 04,2663 BANK 04
038406,000090: 15,2000 SETLOC EPHEM
038407,000091: 15,2000 BANK
038408,000092:
038409,000093: 15,3236 E5,1714 EBANK= VSUN
038410,000094: 15,3236 COUNT* $$/EPHEM
038411,000095: 15,3236 15,3236 LUNPOS EQUALS LSPOS
038412,000096:
038413,000097: 15,3236 54201 LSPOS SETPD SR
038414,000098: 15,3237 00001 0
038415,000099: 15,3240 20617 14D # TP
038416,000100: 15,3241 56371 TAD DDV
038417,000101: 15,3242 01707 TEPHEM # TIME OF LAUNCH
038418,000102: 15,3243 31334 CSTODAY # 24 HOURS-8640000 CENTI-SECS/DAY B-33
038419,000103: 15,3244 00031 STORE TIMEP # T IN DAYS
038420,000104: 15,3245 77170 AXT,1 AXT,2
038421,000105: 15,3246 00000 0
038422,000106: 15,3247 00000 0
038423,000107: 15,3250 77614 CLEAR
038424,000108: 15,3251 00274 FREEFLAG # SWITCH BIT
038425,000109: 15,3252 77745 POSITA DLOAD
038426,000110: 15,3253 31314 KONMAT +2 # ZEROS
038427,000111: 15,3254 00027 STORE GTMP
038428,000112: 15,3255 40745 POSITB DLOAD DMP*
038429,000113: 15,3256 00031 TIMEP # T
038430,000114: 15,3257 31360 VAL67 +4,1 # 1/27 OR 1/32 OR 1/365
038431,000115: 15,3260 42661 SL DAD*
038432,000116: 15,3261 20211 8D
038433,000117: 15,3262 31356 VAL67 +2,1 # AARG
038434,000118: 15,3263 40756 SIN DMP* # SIN(T/27+PHI) OR T/32 OR T/365
038435,000119: 15,3264 31354 VAL67,1 # (A0**2+A1**2)**1/2 SIN(X+PHIA)
038436,000120: 15,3265 62015 DAD INCR,1 # PLUS
038437,000121: 15,3266 00027 GTMP # (B0**2+B1**2)**1/2 SIN(X+PHIB)
038438,000122: 15,3267 77771 DEC -6 B-14
038439,000123: 15,3270 00027 STORE GTMP # OR (C0**2+C1**2)**1/2 SIN(X+PHIC)
038440,000124: 15,3271 77614 BOFSET
038441,000125: 15,3272 00054 FREEFLAG
038442,000126: 15,3273 33255 POSITB
038443,000127: 15,3274 40745 POSITD DLOAD DMP*
038444,000128: 15,3275 00031 TIMEP # T
038445,000129: 15,3276 46437 RATESP,2 # LOMR,LOSR,LONR
038446,000130: 15,3277 42661 SL DAD*
038447,000131: 15,3300 20206 5D
038448,000132: 15,3301 46431 RATESP +6,2 # LOMO,LOSO,LONO
038449,000133: 15,3302 77625 DSU
038450,000134: 15,3303 00027 GTMP
038451,000135: 15,3304 10021 STORE STMP,2 # LOM,LOS,LON
038452,000136: 15,3305 63135 SLOAD INCR,2
038453,000137: 15,3306 00050 X2
038454,000138: 15,3307 77775 DEC -2 B-14
038455,000139: 15,3310 53015 DAD BZE
038456,000140: 15,3311 31336 RCB-13 # PLUS 2
038457,000141: 15,3312 33342 POSITE # 2ND
038458,000142: 15,3313 77644 BPL
038459,000143: 15,3314 33252 POSITA # 1ST
038460,000144: 15,3315 45345 POSITF DLOAD DSU # 3RD
038461,000145: 15,3316 00021 STMP # LOM
038462,000146: 15,3317 00025 STMP +4 # LON
038463,000147: 15,3320 65356 SIN PDDL # SIN(LOM-LON)
038464,000148: 15,3321 00021 STMP
038465,000149: 15,3322 65356 SIN PDDL # SIN LOM
038466,000150: 15,3323 00021 STMP
038467,000151: 15,3324 55546 COS VDEF # COS LOM
038468,000152: 15,3325 53521 MXV UNIT
038469,000153: 15,3326 31312 KONMAT # K1,K2,K3,K4,
038470,000154: 15,3327 02723 STORE VMOON
038471,000155: 15,3330 65345 DLOAD PDDL
038472,000156: 15,3331 31314 KONMAT +2 # ZERO
038473,000157: 15,3332 00023 STMP +2
038474,000158: 15,3333 65356 SIN PDDL # SIN LOS
038475,000159: 15,3334 00023 STMP +2
038476,000160: 15,3335 55546 COS VDEF # COS LOS
038477,000161: 15,3336 53521 MXV UNIT
038478,000162: 15,3337 31312 KONMAT
038479,000163: 15,3340 02715 STORE VSUN
038480,000164: 15,3341 77616 RVQ
038481,000165: 15,3342 77745 POSITE DLOAD
038482,000166: 15,3343 31314 KONMAT +2 # ZEROS
038483,000167: 15,3344 00027 STORE GTMP
038484,000168: 15,3345 77650 GOTO
038485,000169: 15,3346 33274 POSITD
038486,000170: 15,3347 77616 LUNVEL RVQ # TO FOOL INTEGRATION
038487,000171:
038488,000172: 15,3350 STMP EQUALS 16D
038489,000173:
038490,000174: 15,3350 GTMP EQUALS 22D
038491,000175:
038492,000176: 15,3350 TIMEP EQUALS 24D
038493,000177:
038494,000178: 14,2000 SETLOC EPHEM1
038495,000179: 14,2000 BANK
038496,000180: 14,3311 COUNT* $$/EPHEM
038497,000181:
038498,000182: 14,3311 20000 00000 KONMAT 2DEC 1.0 B-1 # *************
038499,000183: 14,3313 00000 00000 2DEC 0 B-28 # *
038500,000184: 14,3315 00000 00000 2DEC 0 B-28 # *
038501,000185: 14,3317 00000 00000 2DEC 0 B-28 # *
038502,000186: 14,3321 16533 30007 2DEC .91745 B-1 # K1 COS(OBL) *
038503,000187: 14,3323 77333 56654 2DEC -.03571 B-1 # K2 SIN(OBL)SIN(IM) *
038504,000188: 14,3325 00000 00000 2DEC 0 B-28 # *
038505,000189: 14,3327 06273 03275 2DEC .39784 B-1 # K3 SIN(OBL) *
038506,000190:
038507,000191: 14,3331 01242 24467 2DEC .082354 B-1 # K4 COS(OBL)SIN(IM) *
038508,000192: 14,3333 00020 17260 CSTODAY 2DEC 8640000 B-33 # * NOTE *
038509,000193: 14,3335 00002 RCB-13 OCT 00002 # * TABLES CONTAIN *
038510,000194: 14,3336 00000 OCT 00000 # * CONSTANTS FOR *
038511,000195: 14,3337 22572 27214 RATESP 2DEC .03660098 B+4 # * 1968 - 1969 *
038512,000196: 14,3341 01315 26177 2DEC .00273779 B+4 # LOSR *
038513,000197: 14,3343 77731 55217 2DEC -.00014719 B+4 # LONR *
038514,000198: 14,3345 16455 04475 2DEC .455880394 # LOMO *
038515,000199: 14,3347 10637 04312 2DEC .275337971 # LOSO *
038516,000200: 14,3351 01215 26351 2DEC .0398987882 # LONO *
038517,000201: 14,3353 01070 35243 VAL67 2DEC .017361944 B+1 # AMOD *
038518,000202: 14,3355 11126 14467 2DEC .286523072 # AARG *
038519,000203: 14,3357 02245 06475 2DEC .036291712 B+1 # 1/27 *
038520,000204: 14,3361 00163 32331 2DEC .003534722 B+1 # BMOD *
038521,000205: 14,3363 03476 03302 2DEC .113165625 # BARG *
038522,000206: 14,3365 02000 00000 2DEC .03125 B+1 # 1/32 *
038523,000207: 14,3367 00256 25374 2DEC .005330555 B+1 # CMOD *
038524,000208: 14,3371 77525 53143 2DEC -.010415660 # CARG VALUE COMPUTED USING 1/364.24
038525,000209: 14,3373 00131 26730 2DEC .002737925 B+1 # 1/365 *************
038526,000210: # ************************************************************************
End of include-file LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc. Parent file is MAIN.agc