Source Code
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These source-code files were from the printout at the MIT Museum, with many thanks
to Deborah Douglas, the Museum's Curator of Science and Technology, for releasing
it to us. The printout was digitally photographed by Paul Fjeld. A team of
volunteers transcribed the source code manually from these images or, where
appropriate, modified already-transcribed but similar source Luminary 131 (Apollo 13)
source code to agree with the images from the printout. Note that the page images
presented online are of reduced quality, and that higher-quality images
are available. Report any conversion errors or legibility
problems in page images to info@sandroid.org.
Notations on the program listing read, in part:GAP: ASSEMBLE REVISION 001 OF AGC PROGRAM LMY99 BY NASA 2021112-061 20'35 OCT. 28,1968Note that the date is the date of the printout, not the date of the program revision. |
013418,000002: ## Copyright: Public domain.
013419,000003: ## Filename: LEM_GEOMETRY.agc
013420,000004: ## Purpose: Part of the source code for Luminary 1A build 099.
013421,000005: ## It is part of the source code for the Lunar Module's (LM)
013422,000006: ## Apollo Guidance Computer (AGC), for Apollo 11.
013423,000007: ## Assembler: yaYUL
013424,000008: ## Contact: Ron Burkey <info@sandroid.org>.
013425,000009: ## Website: www.ibiblio.org/apollo.
013426,000010: ## Pages: 320-325
013427,000011: ## Mod history: 2009-05-16 RSB Adapted from the corresponding
013428,000012: ## Luminary131 file, using page
013429,000013: ## images from Luminary 1A.
013430,000014: ## 2016-12-13 RSB Proofed text comments with octopus/ProoferComments
013431,000015: ## and corrected the errors found.
013432,000016: ## 2017-03-07 RSB Fixed comment-text error noticed while proofing
013433,000017: ## Luminary 116.
013434,000018: ##
013435,000019: ## This source code has been transcribed or otherwise adapted from
013436,000020: ## digitized images of a hardcopy from the MIT Museum. The digitization
013437,000021: ## was performed by Paul Fjeld, and arranged for by Deborah Douglas of
013438,000022: ## the Museum. Many thanks to both. The images (with suitable reduction
013439,000023: ## in storage size and consequent reduction in image quality as well) are
013440,000024: ## available online at www.ibiblio.org/apollo. If for some reason you
013441,000025: ## find that the images are illegible, contact me at info@sandroid.org
013442,000026: ## about getting access to the (much) higher-quality images which Paul
013443,000027: ## actually created.
013444,000028: ##
013445,000029: ## Notations on the hardcopy document read, in part:
013446,000030: ##
013447,000031: ## Assemble revision 001 of AGC program LMY99 by NASA 2021112-61
013448,000032: ## 16:27 JULY 14, 1969
013449,000033:
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Page 320 |
013451,000035: 23,2041 BANK 23
013452,000036: 13,2000 SETLOC LEMGEOM
013453,000037: 13,2000 BANK
013454,000038:
013455,000039: 13,2070 30,2000 SBANK= LOWSUPER
013456,000040: 13,2070 E5,1642 EBANK= XSM
013457,000041:
013458,000042: # THESE TWO ROUTINES COMPUTE THE ACTUAL STATE VECTOR FOR LM,CSM BY ADDING
013459,000043: # THE CONIC R,V AND THE DEVIATIONS R,V. THE STATE VECTORS ARE CONVERTED TO
013460,000044: # METERS B-29 AND METERS/CSEC B-7 AND STORED APPROPRIATELY IN RN,VN OR
013461,000045: # R-OTHER,V-OTHER FOR DOWNLINK. THE ROUTINES NAMES ARE SWITCHED IN THE
013462,000046: # OTHER VEHICLES COMPUTER.
013463,000047:
013464,000048: # INPUT
013465,000049: # STATE VECTOR IN TEMPORARY STORAGE AREA
013466,000050: # IF STATE VECTOR IS SCALED POS B27 AND VEL B5
013467,000051: # SET X2 TO +2
013468,000052: # IF STATE VECTOR IS SCALED POS B29 AND VEL B7
013469,000053: # SET X2 TO 0
013470,000054:
013471,000055: # OUTPUT
013472,000056: # R(T) IN RN, V(T) IN VN, T IN PIPTIME
013473,000057: # OR
013474,000058: # R(T) IN R-OTHER, V(T) IN V-OTHER (T IS DEFINED BY T-OTHER)
013475,000059:
013476,000060: 13,2070 COUNT* $$/GEOM
013477,000061: 13,2070 43414 SVDWN2 BOF RVQ # SW=1=AVETOMID DOING W-MATRIX INTEG.
013478,000062: 13,2071 04756 AVEMIDSW
013479,000063: 13,2072 26073 +1
013480,000064: 13,2073 53775 VLOAD VSL*
013481,000065: 13,2074 01521 TDELTAV
013482,000066: 13,2075 57605 0 -7,2
013483,000067: 13,2076 53655 VAD VSL*
013484,000068: 13,2077 01535 RCV
013485,000069: 13,2100 57576 0,2
013486,000070: 13,2101 25221 STOVL RN
013487,000071: 13,2102 01527 TNUV
013488,000072: 13,2103 53257 VSL* VAD
013489,000073: 13,2104 57602 0 -4,2
013490,000074: 13,2105 01543 VCV
013491,000075: 13,2106 77657 VSL*
013492,000076: 13,2107 57576 0,2
013493,000077: 13,2110 15227 STODL VN
013494,000078: 13,2111 01517 TET
013495,000079: 13,2112 01235 STORE PIPTIME
013496,000080: 13,2113 77616 RVQ
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Page 321 |
013498,000082: 13,2114 53775 SVDWN1 VLOAD VSL*
013499,000083: 13,2115 01521 TDELTAV
013500,000084: 13,2116 57605 0 -7,2
013501,000085: 13,2117 53655 VAD VSL*
013502,000086: 13,2120 01535 RCV
013503,000087: 13,2121 57576 0,2
013504,000088: 13,2122 25720 STOVL R-OTHER
013505,000089: 13,2123 01527 TNUV
013506,000090: 13,2124 53257 VSL* VAD
013507,000091: 13,2125 57602 0 -4,2
013508,000092: 13,2126 01543 VCV
013509,000093: 13,2127 77657 VSL*
013510,000094: 13,2130 57576 0,2
013511,000095: 13,2131 01726 STORE V-OTHER
013512,000096: 13,2132 77616 RVQ
013513,000097:
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Page 322 |
013515,000099: # THE FOLLOWING ROUTINE TAKES A HALF UNIT TARGET VECTOR REFERRED TO NAV BASE COORDINATES AND FINDS BOTH
013516,000100: # GIMBAL ORIENTATIONS AT WHICH THE RR MIGHT SIGHT THE TARGET. THE GIMBAL ANGLES CORRESPONDING TO THE PRESENT MODE
013517,000101: # ARE LEFT IN MODEA AND THOSE WHICH WOULD BE USED AFTER A REMODE IN MODEB. THIS ROUTINE ASSUMES MODE 1 IS TRUNNION
013518,000102: # ANGLE LESS THAN 90 DEGS IN ABS VALUE WITH ARBITRARY SHAFT, WITH A CORRESPONDING DEFINITION FOR MODE 2. MODE
013519,000103: # SELECTION AND LIMIT CHECKING ARE DONE ELSEWHERE.
013520,000104:
013521,000105: # THE MODE 1 CONFIGURATION IS CALCULATED FROM THE VECTOR AND THEN MODE 2 IS FOUND USING THE RELATIONS
013522,000106:
013523,000107: # S(2) = 180 + S(1)
013524,000108: # T(2) = 180 - T(1)
013525,000109:
013526,000110: # THE VECTOR ARRIVES IN MPAC WHERE TRG*SMNG OR *SMNB* WILL HAVE LEFT IT.
013527,000111:
013528,000112: 13,2133 00041 RRANGLES STORE 32D
013529,000113: 13,2134 57545 DLOAD DCOMP # SINCE WE WILL FIND THE MODE 1 SHAFT
013530,000114: 13,2135 00043 34D # ANGLE LATER, WE CAN FIND THE MODE 1
013531,000115: 13,2136 67401 SETPD ASIN # TRUNNION BY SIMPLY TAKING THE ARCSIN OF
013532,000116: 13,2137 00001 0 # THE Y COMPONENT, THE ASIN GIVING AN
013533,000117: 13,2140 44206 PUSH BDSU # ANSWER WHOSE ABS VAL IS LESS THAN 90 DEG
013534,000118: 13,2141 24005 LODPHALF
013535,000119: 13,2142 14005 STODL 4 # MODE 2 TRUNNION TO 4.
013536,000120:
013537,000121: 13,2143 24007 LO6ZEROS
013538,000122: 13,2144 24043 STOVL 34D # UNIT THE PROJECTION OF THE VECTOR
013539,000123: 13,2145 00041 32D # IN THE X-Z PLANE
013540,000124: 13,2146 41056 UNIT BOVB # IF OVERFLOW, TARGET VECTOR IS ALONG Y
013541,000125: 13,2147 52421 LUNDESCH # CALL FOR MANEUVER UNLESS ON LUNAR SURF
013542,000126: 13,2150 14041 STODL 32D # PROJECTION VECTOR.
013543,000127: 13,2151 00041 32D
013544,000128: 13,2152 44142 SR1 STQ
013545,000129: 13,2153 00051 S2
013546,000130: 13,2154 14023 STODL SINTH # USE ARCTRIG SINCE SHAFT COULD BE ARB.
013547,000131: 13,2155 00045 36D
013548,000132: 13,2156 77742 SR1
013549,000133: 13,2157 34021 STCALL COSTH
013550,000134: 13,2160 47320 ARCTRIG
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Page 323 |
013552,000136: 13,2161 43206 PUSH DAD # MODE 1 SHAFT TO 2.
013553,000137: 13,2162 24005 LODPHALF
013554,000138: 13,2163 24007 STOVL 6
013555,000139: 13,2164 00005 4
013556,000140: 13,2165 77634 RTB # FIND MODE 2 CDU ANGLES.
013557,000141: 13,2166 21635 2V1STO2S
013558,000142: 13,2167 25112 STOVL MODEB
013559,000143: 13,2170 00001 0
013560,000144: 13,2171 77634 RTB # MODE 1 ANGLES TO MODE A.
013561,000145: 13,2172 21635 2V1STO2S
013562,000146: 13,2173 01110 STORE MODEA
013563,000147: 13,2174 77776 EXIT
013564,000148:
013565,000149: 13,2175 40110 CS RADMODES # SWAP MODEA AND MODEB IF RR IN MODE 2.
013566,000150: 13,2176 74740 MASK ANTENBIT
013567,000151: 13,2177 10000 CCS A
013568,000152: 13,2200 12204 TCF +4
013569,000153:
013570,000154: 13,2201 53110 DXCH MODEA
013571,000155: 13,2202 53112 DXCH MODEB
013572,000156: 13,2203 53110 DXCH MODEA
013573,000157:
013574,000158: 13,2204 06037 TC INTPRET
013575,000159: 13,2205 77650 GOTO
013576,000160: 13,2206 00051 S2
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Page 324 |
013578,000162: # GIVEN RR TRUNNION AND SHAFT (T,S) IN TANGNB,+1, FIND THE ASSOCIATED
013579,000163: # LINE OF SIGHT IN NAV BASE AXES. THE HALF UNIT VECTOR, .5(SIN(S)COS(T),
013580,000164: # -SIN(T),COS(S)COS(T)) IS LEFT IN MPAC AND 32D.
013581,000165:
013582,000166: 23,2000 SETLOC INFLIGHT
013583,000167: 23,2000 BANK
013584,000168:
013585,000169: 23,2041 COUNT* $$/GEOM
013586,000170:
013587,000171: 23,2041 47135 RRNB SLOAD RTB
013588,000172: 23,2042 03753 TANGNB
013589,000173: 23,2043 21576 CDULOGIC
013590,000174: 23,2044 41401 SETPD PUSH # TRUNNION ANGLE TO 0
013591,000175: 23,2045 00001 0
013592,000176: 23,2046 57556 SIN DCOMP
013593,000177: 23,2047 14043 STODL 34D # Y COMPONENT
013594,000178:
013595,000179: 23,2050 41546 COS PUSH # .5 COS(T) TO 0
013596,000180: 23,2051 47135 SLOAD RTB
013597,000181: 23,2052 03754 TANGNB +1
013598,000182: 23,2053 21576 CDULOGIC
013599,000183: 23,2054 71406 RRNB1 PUSH COS # SHAFT ANGLE TO 2
013600,000184: 23,2055 72405 DMP SL1
013601,000185: 23,2056 00001 0
013602,000186: 23,2057 14045 STODL 36D # Z COMPONENT
013603,000187:
013604,000188: 23,2060 41356 SIN DMP
013605,000189: 23,2061 77752 SL1
013606,000190: 23,2062 24041 STOVL 32D
013607,000191: 23,2063 00041 32D
013608,000192: 23,2064 77616 RVQ
013609,000193:
013610,000194: # THIS ENTRY TO RRNB REQUIRES THE TRUNNION AND SHAFT ANGLES IN MPAC AND MPAC +1 RESPECTIVELY
013611,000195:
013612,000196: 23,2065 14025 RRNBMPAC STODL 20D # SAVE SHAFT CDU IN 21.
013613,000197: 23,2066 00155 MPAC # SET MODE TO DP. (THE PRECEEDING STORE
013614,000198: # MAY BE DP, TP OR VECTOR.)
013615,000199: 23,2067 40234 RTB SETPD
013616,000200: 23,2070 21576 CDULOGIC
013617,000201: 23,2071 00001 0
013618,000202: 23,2072 73406 PUSH SIN # TRUNNION ANGLE TO 0
013619,000203: 23,2073 77676 DCOMP
013620,000204: 23,2074 14043 STODL 34D # Y COMPONENT
013621,000205: 23,2075 41546 COS PUSH # .5COS(T) TO 0
013622,000206: 23,2076 47135 SLOAD RTB # PICK UP CDU'S.
013623,000207: 23,2077 00026 21D
013624,000208: 23,2100 21576 CDULOGIC
013625,000209: 23,2101 77650 GOTO
013626,000210: 23,2102 46054 RRNB1
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Page 325
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013629,000213:
013630,000214:
End of include-file LEM_GEOMETRY.agc. Parent file is MAIN.agc