Source Code
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This is an attempt to recreate Luminary 99 Rev 2, otherwise known as LUM99R2, from Luminary 99 Rev 1 and ephemeris data from Luminary 116. The differences are confined to the last 10-12 lines of the CONTROLLED CONSTANTS. Luminary 99 Rev 1 source-code was transcribed from a printout in the MIT Museum, while Luminary 116 source code was transcribed from a printout belonging to Don Eyles. AGC developer James Kernan, the "rope mother" for the Apollo 11 Lunar Module's AGC, explains as follows: "At the last minute, Dan Lickly, our chief engineer, appeared with ephemerides updates and it took two tries to get it right. The result was that we created Lum99 Revision 1 and Lum99 Revision 2." It is suspected that the former is what's in the MIT Museum, and the latter is what we are trying to recreate here. As for which revision actually flew in Apollo 11, all of the other available surviving evidence points to Rev 1 rather than to Rev 2, so we're just not sure! |
013141,000002: ## Copyright: Public domain.
013142,000003: ## Filename: LEM_GEOMETRY.agc
013143,000004: ## Purpose: Part of the source code for Luminary 1A build 099.
013144,000005: ## It is part of the source code for the Lunar Module's (LM)
013145,000006: ## Apollo Guidance Computer (AGC), for Apollo 11.
013146,000007: ## Assembler: yaYUL
013147,000008: ## Contact: Ron Burkey <info@sandroid.org>.
013148,000009: ## Website: www.ibiblio.org/apollo.
013149,000010: ## Pages: 320-325
013150,000011: ## Mod history: 2009-05-16 RSB Adapted from the corresponding
013151,000012: ## Luminary131 file, using page
013152,000013: ## images from Luminary 1A.
013153,000014: ## 2016-12-13 RSB Proofed text comments with octopus/ProoferComments
013154,000015: ## and corrected the errors found.
013155,000016: ## 2017-03-03 RSB Snapshot of Luminary 99 Rev 1.
013156,000017: ## 2017-03-07 RSB Fixed comment-text error noticed while proofing
013157,000018: ## Luminary 116.
013158,000019:
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Page 320 |
013160,000021: 23,2041 BANK 23
013161,000022: 13,2000 SETLOC LEMGEOM
013162,000023: 13,2000 BANK
013163,000024:
013164,000025: 13,2070 30,2000 SBANK= LOWSUPER
013165,000026: 13,2070 E5,1642 EBANK= XSM
013166,000027:
013167,000028: # THESE TWO ROUTINES COMPUTE THE ACTUAL STATE VECTOR FOR LM,CSM BY ADDING
013168,000029: # THE CONIC R,V AND THE DEVIATIONS R,V. THE STATE VECTORS ARE CONVERTED TO
013169,000030: # METERS B-29 AND METERS/CSEC B-7 AND STORED APPROPRIATELY IN RN,VN OR
013170,000031: # R-OTHER,V-OTHER FOR DOWNLINK. THE ROUTINES NAMES ARE SWITCHED IN THE
013171,000032: # OTHER VEHICLES COMPUTER.
013172,000033:
013173,000034: # INPUT
013174,000035: # STATE VECTOR IN TEMPORARY STORAGE AREA
013175,000036: # IF STATE VECTOR IS SCALED POS B27 AND VEL B5
013176,000037: # SET X2 TO +2
013177,000038: # IF STATE VECTOR IS SCALED POS B29 AND VEL B7
013178,000039: # SET X2 TO 0
013179,000040:
013180,000041: # OUTPUT
013181,000042: # R(T) IN RN, V(T) IN VN, T IN PIPTIME
013182,000043: # OR
013183,000044: # R(T) IN R-OTHER, V(T) IN V-OTHER (T IS DEFINED BY T-OTHER)
013184,000045:
013185,000046: 13,2070 COUNT* $$/GEOM
013186,000047: 13,2070 43414 SVDWN2 BOF RVQ # SW=1=AVETOMID DOING W-MATRIX INTEG.
013187,000048: 13,2071 04756 AVEMIDSW
013188,000049: 13,2072 26073 +1
013189,000050: 13,2073 53775 VLOAD VSL*
013190,000051: 13,2074 01521 TDELTAV
013191,000052: 13,2075 57605 0 -7,2
013192,000053: 13,2076 53655 VAD VSL*
013193,000054: 13,2077 01535 RCV
013194,000055: 13,2100 57576 0,2
013195,000056: 13,2101 25221 STOVL RN
013196,000057: 13,2102 01527 TNUV
013197,000058: 13,2103 53257 VSL* VAD
013198,000059: 13,2104 57602 0 -4,2
013199,000060: 13,2105 01543 VCV
013200,000061: 13,2106 77657 VSL*
013201,000062: 13,2107 57576 0,2
013202,000063: 13,2110 15227 STODL VN
013203,000064: 13,2111 01517 TET
013204,000065: 13,2112 01235 STORE PIPTIME
013205,000066: 13,2113 77616 RVQ
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Page 321 |
013207,000068: 13,2114 53775 SVDWN1 VLOAD VSL*
013208,000069: 13,2115 01521 TDELTAV
013209,000070: 13,2116 57605 0 -7,2
013210,000071: 13,2117 53655 VAD VSL*
013211,000072: 13,2120 01535 RCV
013212,000073: 13,2121 57576 0,2
013213,000074: 13,2122 25720 STOVL R-OTHER
013214,000075: 13,2123 01527 TNUV
013215,000076: 13,2124 53257 VSL* VAD
013216,000077: 13,2125 57602 0 -4,2
013217,000078: 13,2126 01543 VCV
013218,000079: 13,2127 77657 VSL*
013219,000080: 13,2130 57576 0,2
013220,000081: 13,2131 01726 STORE V-OTHER
013221,000082: 13,2132 77616 RVQ
013222,000083:
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Page 322 |
013224,000085: # THE FOLLOWING ROUTINE TAKES A HALF UNIT TARGET VECTOR REFERRED TO NAV BASE COORDINATES AND FINDS BOTH
013225,000086: # GIMBAL ORIENTATIONS AT WHICH THE RR MIGHT SIGHT THE TARGET. THE GIMBAL ANGLES CORRESPONDING TO THE PRESENT MODE
013226,000087: # ARE LEFT IN MODEA AND THOSE WHICH WOULD BE USED AFTER A REMODE IN MODEB. THIS ROUTINE ASSUMES MODE 1 IS TRUNNION
013227,000088: # ANGLE LESS THAN 90 DEGS IN ABS VALUE WITH ARBITRARY SHAFT, WITH A CORRESPONDING DEFINITION FOR MODE 2. MODE
013228,000089: # SELECTION AND LIMIT CHECKING ARE DONE ELSEWHERE.
013229,000090:
013230,000091: # THE MODE 1 CONFIGURATION IS CALCULATED FROM THE VECTOR AND THEN MODE 2 IS FOUND USING THE RELATIONS
013231,000092:
013232,000093: # S(2) = 180 + S(1)
013233,000094: # T(2) = 180 - T(1)
013234,000095:
013235,000096: # THE VECTOR ARRIVES IN MPAC WHERE TRG*SMNG OR *SMNB* WILL HAVE LEFT IT.
013236,000097:
013237,000098: 13,2133 00041 RRANGLES STORE 32D
013238,000099: 13,2134 57545 DLOAD DCOMP # SINCE WE WILL FIND THE MODE 1 SHAFT
013239,000100: 13,2135 00043 34D # ANGLE LATER, WE CAN FIND THE MODE 1
013240,000101: 13,2136 67401 SETPD ASIN # TRUNNION BY SIMPLY TAKING THE ARCSIN OF
013241,000102: 13,2137 00001 0 # THE Y COMPONENT, THE ASIN GIVING AN
013242,000103: 13,2140 44206 PUSH BDSU # ANSWER WHOSE ABS VAL IS LESS THAN 90 DEG
013243,000104: 13,2141 24005 LODPHALF
013244,000105: 13,2142 14005 STODL 4 # MODE 2 TRUNNION TO 4.
013245,000106:
013246,000107: 13,2143 24007 LO6ZEROS
013247,000108: 13,2144 24043 STOVL 34D # UNIT THE PROJECTION OF THE VECTOR
013248,000109: 13,2145 00041 32D # IN THE X-Z PLANE
013249,000110: 13,2146 41056 UNIT BOVB # IF OVERFLOW, TARGET VECTOR IS ALONG Y
013250,000111: 13,2147 52421 LUNDESCH # CALL FOR MANEUVER UNLESS ON LUNAR SURF
013251,000112: 13,2150 14041 STODL 32D # PROJECTION VECTOR.
013252,000113: 13,2151 00041 32D
013253,000114: 13,2152 44142 SR1 STQ
013254,000115: 13,2153 00051 S2
013255,000116: 13,2154 14023 STODL SINTH # USE ARCTRIG SINCE SHAFT COULD BE ARB.
013256,000117: 13,2155 00045 36D
013257,000118: 13,2156 77742 SR1
013258,000119: 13,2157 34021 STCALL COSTH
013259,000120: 13,2160 47320 ARCTRIG
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Page 323 |
013261,000122: 13,2161 43206 PUSH DAD # MODE 1 SHAFT TO 2.
013262,000123: 13,2162 24005 LODPHALF
013263,000124: 13,2163 24007 STOVL 6
013264,000125: 13,2164 00005 4
013265,000126: 13,2165 77634 RTB # FIND MODE 2 CDU ANGLES.
013266,000127: 13,2166 21635 2V1STO2S
013267,000128: 13,2167 25112 STOVL MODEB
013268,000129: 13,2170 00001 0
013269,000130: 13,2171 77634 RTB # MODE 1 ANGLES TO MODE A.
013270,000131: 13,2172 21635 2V1STO2S
013271,000132: 13,2173 01110 STORE MODEA
013272,000133: 13,2174 77776 EXIT
013273,000134:
013274,000135: 13,2175 40110 CS RADMODES # SWAP MODEA AND MODEB IF RR IN MODE 2.
013275,000136: 13,2176 74740 MASK ANTENBIT
013276,000137: 13,2177 10000 CCS A
013277,000138: 13,2200 12204 TCF +4
013278,000139:
013279,000140: 13,2201 53110 DXCH MODEA
013280,000141: 13,2202 53112 DXCH MODEB
013281,000142: 13,2203 53110 DXCH MODEA
013282,000143:
013283,000144: 13,2204 06037 TC INTPRET
013284,000145: 13,2205 77650 GOTO
013285,000146: 13,2206 00051 S2
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Page 324 |
013287,000148: # GIVEN RR TRUNNION AND SHAFT (T,S) IN TANGNB,+1, FIND THE ASSOCIATED
013288,000149: # LINE OF SIGHT IN NAV BASE AXES. THE HALF UNIT VECTOR, .5(SIN(S)COS(T),
013289,000150: # -SIN(T),COS(S)COS(T)) IS LEFT IN MPAC AND 32D.
013290,000151:
013291,000152: 23,2000 SETLOC INFLIGHT
013292,000153: 23,2000 BANK
013293,000154:
013294,000155: 23,2041 COUNT* $$/GEOM
013295,000156:
013296,000157: 23,2041 47135 RRNB SLOAD RTB
013297,000158: 23,2042 03753 TANGNB
013298,000159: 23,2043 21576 CDULOGIC
013299,000160: 23,2044 41401 SETPD PUSH # TRUNNION ANGLE TO 0
013300,000161: 23,2045 00001 0
013301,000162: 23,2046 57556 SIN DCOMP
013302,000163: 23,2047 14043 STODL 34D # Y COMPONENT
013303,000164:
013304,000165: 23,2050 41546 COS PUSH # .5 COS(T) TO 0
013305,000166: 23,2051 47135 SLOAD RTB
013306,000167: 23,2052 03754 TANGNB +1
013307,000168: 23,2053 21576 CDULOGIC
013308,000169: 23,2054 71406 RRNB1 PUSH COS # SHAFT ANGLE TO 2
013309,000170: 23,2055 72405 DMP SL1
013310,000171: 23,2056 00001 0
013311,000172: 23,2057 14045 STODL 36D # Z COMPONENT
013312,000173:
013313,000174: 23,2060 41356 SIN DMP
013314,000175: 23,2061 77752 SL1
013315,000176: 23,2062 24041 STOVL 32D
013316,000177: 23,2063 00041 32D
013317,000178: 23,2064 77616 RVQ
013318,000179:
013319,000180: # THIS ENTRY TO RRNB REQUIRES THE TRUNNION AND SHAFT ANGLES IN MPAC AND MPAC +1 RESPECTIVELY
013320,000181:
013321,000182: 23,2065 14025 RRNBMPAC STODL 20D # SAVE SHAFT CDU IN 21.
013322,000183: 23,2066 00155 MPAC # SET MODE TO DP. (THE PRECEEDING STORE
013323,000184: # MAY BE DP, TP OR VECTOR.)
013324,000185: 23,2067 40234 RTB SETPD
013325,000186: 23,2070 21576 CDULOGIC
013326,000187: 23,2071 00001 0
013327,000188: 23,2072 73406 PUSH SIN # TRUNNION ANGLE TO 0
013328,000189: 23,2073 77676 DCOMP
013329,000190: 23,2074 14043 STODL 34D # Y COMPONENT
013330,000191: 23,2075 41546 COS PUSH # .5COS(T) TO 0
013331,000192: 23,2076 47135 SLOAD RTB # PICK UP CDU'S.
013332,000193: 23,2077 00026 21D
013333,000194: 23,2100 21576 CDULOGIC
013334,000195: 23,2101 77650 GOTO
013335,000196: 23,2102 46054 RRNB1
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Page 325 |
013337,000198: # (This page has nothing on it.)
013338,000199:
013339,000200:
End of include-file LEM_GEOMETRY.agc. Parent file is MAIN.agc