Source Code
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These source-code files are part of a reconstructed copy of Luminary 178, the
final release of the Apollo 14 Lunar Module (LM) Apollo Guidance Computer
(AGC) software.
The reconstruction began with source code of Zerlina 56, Luminary 210, and
Luminary 131, previously transcribed from digitized copies of those programs.
The code was created by combining the three, using Zerlina 56 as a base, since
it was based off of Luminary 183. The differences between the three were
carefully merged using the Luminary memos as a guide, with all changes made
after Luminary 178 being backed out. The reconstruction was verified by matching
memory-bank checksums to those listed in drawing 2021152N. Note that page numbers
in the reconstructed code match those for the baseline log section mentioned in
each file's changelog; the page numbers for a real Luminary 178 listing would
be different.
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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013961,000002: ## Copyright: Public domain.
013962,000003: ## Filename: LEM_GEOMETRY.agc
013963,000004: ## Purpose: A section of Luminary revision 178.
013964,000005: ## It is part of the reconstructed source code for the final
013965,000006: ## release of the flight software for the Lunar Module's
013966,000007: ## (LM) Apollo Guidance Computer (AGC) for Apollo 14. The
013967,000008: ## code has been recreated from copies of Zerlina 56, Luminary
013968,000009: ## 210, and Luminary 131, as well as many Luminary memos.
013969,000010: ## It has been adapted such that the resulting bugger words
013970,000011: ## exactly match those specified for Luminary 178 in NASA
013971,000012: ## drawing 2021152N, which gives relatively high confidence
013972,000013: ## that the reconstruction is correct.
013973,000014: ## Reference: pp. 325-330
013974,000015: ## Assembler: yaYUL
013975,000016: ## Contact: Ron Burkey <info@sandroid.org>.
013976,000017: ## Website: www.ibiblio.org/apollo/index.html
013977,000018: ## Mod history: 2019-08-14 MAS Created from Zerlina 56.
013978,000019:
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Page 332
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013980,000021: 23,2041 BANK 23
013981,000022: 13,2000 SETLOC LEMGEOM
013982,000023: 13,2000 BANK
013983,000024:
013984,000025: 13,2070 30,2000 SBANK= LOWSUPER
013985,000026: 13,2070 E5,1642 EBANK= XSM
013986,000027:
013987,000028: # THESE TWO ROUTINES COMPUTE THE ACTUAL STATE VECTOR FOR LM,CSM BY ADDING
013988,000029: # THE CONIC R,V AND THE DEVIATIONSR,V. THE STATE VECTORS ARE CONVERTED TO
013989,000030: # METERS B-29 AND METERS/CSEC B-7 AND STORED APPROPRIATELY IN RN,VN OR
013990,000031: # R-OTHER , V-OTHER FOR DOWNLINK. THE ROUTINES NAMES ARE SWITCHED IN THE
013991,000032: # OTHER VEHICLES COMPUTER.
013992,000033:
013993,000034: # INPUT
013994,000035: # STATE VECTOR IN TEMPORARY STORAGE AREA
013995,000036: # IF STATE VECTOR IS SCALED POS B27 AND VEL B5
013996,000037: # SET X2 TO +2
013997,000038: # IF STATE VECTOR IS SCALED POS B29 AND VEL B7
013998,000039: # SET X2 TO 0
013999,000040:
014000,000041: # OUTPUT
014001,000042: # R(T) IN RN, V(T) IN VN, T IN PIPTIME
014002,000043: # OR
014003,000044: # R(T) IN R-OTHER, V(T) IN V-OTHER (T IS DEFINED BY T-OTHER)
014004,000045:
014005,000046: 13,2070 COUNT* $$/GEOM
014006,000047: 13,2070 43414 SVDWN2 BOF RVQ # SW=1=AVETOMID DOING W-MATRIX INTEG.
014007,000048: 13,2071 04756 AVEMIDSW
014008,000049: 13,2072 26073 +1
014009,000050: 13,2073 53775 VLOAD VSL*
014010,000051: 13,2074 01521 TDELTAV
014011,000052: 13,2075 57605 0 -7,2
014012,000053: 13,2076 53655 VAD VSL*
014013,000054: 13,2077 01535 RCV
014014,000055: 13,2100 57576 0,2
014015,000056: 13,2101 25220 STOVL RN
014016,000057: 13,2102 01527 TNUV
014017,000058: 13,2103 53257 VSL* VAD
014018,000059: 13,2104 57602 0 -4,2
014019,000060: 13,2105 01543 VCV
014020,000061: 13,2106 77657 VSL*
014021,000062: 13,2107 57576 0,2
014022,000063: 13,2110 15226 STODL VN
014023,000064: 13,2111 01517 TET
014024,000065: 13,2112 01234 STORE PIPTIME
014025,000066: 13,2113 77616 RVQ
014026,000067:
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Page 326
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014028,000069: 13,2114 53775 SVDWN1 VLOAD VSL*
014029,000070: 13,2115 01521 TDELTAV
014030,000071: 13,2116 57605 0 -7,2
014031,000072: 13,2117 53655 VAD VSL*
014032,000073: 13,2120 01535 RCV
014033,000074: 13,2121 57576 0,2
014034,000075: 13,2122 25716 STOVL R-OTHER
014035,000076: 13,2123 01527 TNUV
014036,000077: 13,2124 53257 VSL* VAD
014037,000078: 13,2125 57602 0 -4,2
014038,000079: 13,2126 01543 VCV
014039,000080: 13,2127 77657 VSL*
014040,000081: 13,2130 57576 0,2
014041,000082: 13,2131 01724 STORE V-OTHER
014042,000083: 13,2132 77616 RVQ
014043,000084:
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Page 327
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014045,000086: # THE FOLLOWING ROUTINE TAKES A HALF UNIT TARGET VECTOR REFERRED TO NAV BASE COORDINATES AND FINDS BOTH
014046,000087: # GIMBAL ORIENTATIONS AT WHICH THE RR MIGHT SIGHT THE TARGET. THE GIMBAL ANGLES CORRESPONDING TO THE PRESENT MODE
014047,000088: # ARE LEFT IN MODEA AND THOSE WHICH WOULD BE USED AFTER A REMODE IN MODEB. THIS ROUTINE ASSUMES MODE 1 IS TRUNNION
014048,000089: # ANGLE LESS THAN 90 DEGS IN ABS VALUE WITH ARBITRARY SHAFT, WITH A CORRESPONDING DEFINITION FOR MODE 2. MODE
014049,000090: # SELECTION AND LIMIT CHECKING ARE DONE ELSEWHERE.
014050,000091:
014051,000092: # THE MODE 1 CONFIGURATION IS CALCULATED FROM THE VECTOR AND THEN MODE 2 IS FOUND USING THE RELATIONS
014052,000093:
014053,000094: # S(2) = 180 + S(1)
014054,000095: # T(2) = 180 - T(1)
014055,000096:
014056,000097: # THE VECTOR ARRIVES IN MPAC WHERE TRG*SMNG OR *SMNB* WILL HAVE LEFT IT.
014057,000098:
014058,000099: 13,2133 00041 RRANGLES STORE 32D
014059,000100: 13,2134 57545 DLOAD DCOMP # SINCE WE WILL FIND THE MODE 1 SHAFT
014060,000101: 13,2135 00043 34D # ANGLE LATER, WE CAN FIND THE MODE 1
014061,000102: 13,2136 67401 SETPD ASIN # TRUNNION BY SIMPLY TAKING THE ARCSIN OF
014062,000103: 13,2137 00001 0 # THE Y COMPONENT, THE ASIN GIVING AN
014063,000104: 13,2140 44206 PUSH BDSU # ANSWER WHOSE ABS VAL IS LESS THAN 90 DEG
014064,000105: 13,2141 24005 LODPHALF
014065,000106: 13,2142 14005 STODL 4 # MODE 2 TRUNNION TO 4.
014066,000107:
014067,000108: 13,2143 24007 LO6ZEROS
014068,000109: 13,2144 24043 STOVL 34D # UNIT THE PROJECTION OF THE VECTOR
014069,000110: 13,2145 00041 32D # IN THE X-Z PLANE
014070,000111: 13,2146 41056 UNIT BOVB # IF OVERFLOW,TARGET VECTOR IS ALONG Y
014071,000112: 13,2147 52412 LUNDESCH # CALL FOR MANEUVER UNLESS ON LUNAR SURF
014072,000113: 13,2150 14041 STODL 32D # PROJECTION VECTOR.
014073,000114: 13,2151 00041 32D
014074,000115: 13,2152 44142 SR1 STQ
014075,000116: 13,2153 00051 S2
014076,000117: 13,2154 14023 STODL SINTH # USE ARCTRIG SINCE SHAFT COULD BE ARB.
014077,000118: 13,2155 00045 36D
014078,000119: 13,2156 77742 SR1
014079,000120: 13,2157 34021 STCALL COSTH
014080,000121: 13,2160 47266 ARCTRIG
014081,000122:
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Page 328
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014083,000124: 13,2161 43206 PUSH DAD # MODE 1 SHAFT TO 2.
014084,000125: 13,2162 24005 LODPHALF
014085,000126: 13,2163 24007 STOVL 6
014086,000127: 13,2164 00005 4
014087,000128: 13,2165 77634 RTB # FIND MODE 2 CDU ANGLES.
014088,000129: 13,2166 21636 2V1STO2S
014089,000130: 13,2167 25111 STOVL MODEB
014090,000131: 13,2170 00001 0
014091,000132: 13,2171 77634 RTB # MODE 1 ANGLES TO MODE A.
014092,000133: 13,2172 21636 2V1STO2S
014093,000134: 13,2173 01107 STORE MODEA
014094,000135: 13,2174 77776 EXIT
014095,000136:
014096,000137: 13,2175 40110 CS RADMODES # SWAP MODEA AND MODEB IF RR IN MODE 2.
014097,000138: 13,2176 74740 MASK ANTENBIT
014098,000139: 13,2177 10000 CCS A
014099,000140: 13,2200 12204 TCF +4
014100,000141:
014101,000142: 13,2201 53107 DXCH MODEA
014102,000143: 13,2202 53111 DXCH MODEB
014103,000144: 13,2203 53107 DXCH MODEA
014104,000145:
014105,000146: 13,2204 06042 TC INTPRET
014106,000147: 13,2205 77650 GOTO
014107,000148: 13,2206 00051 S2
014108,000149:
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Page 329
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014110,000151: # GIVEN RR TRUNNION AND SHAFT (T,S) IN TANGNB,+1,FIND THE ASSOCIATED
014111,000152: # LINE OF SIGHT IN NAV BASE AXES. THE HALF UNIT VECTOR, .5(SIN(S)COS(T),
014112,000153: # -SIN(T),COS(S)COS(T)) IS LEFT IN MPAC AND 32D.
014113,000154:
014114,000155: 23,2000 SETLOC INFLIGHT
014115,000156: 23,2000 BANK
014116,000157:
014117,000158: 23,2041 COUNT* $$/GEOM
014118,000159:
014119,000160: 23,2041 47135 RRNB SLOAD RTB
014120,000161: 23,2042 03753 TANGNB
014121,000162: 23,2043 21577 CDULOGIC
014122,000163: 23,2044 41401 SETPD PUSH # TRUNNION ANGLE TO 0
014123,000164: 23,2045 00001 0
014124,000165: 23,2046 57556 SIN DCOMP
014125,000166: 23,2047 14043 STODL 34D # Y COMPONENT
014126,000167:
014127,000168: 23,2050 41546 COS PUSH # .5 COS(T) TO 0
014128,000169: 23,2051 47135 SLOAD RTB
014129,000170: 23,2052 03754 TANGNB +1
014130,000171: 23,2053 21577 CDULOGIC
014131,000172: 23,2054 71406 RRNB1 PUSH COS # SHAFT ANGLE TO 2
014132,000173: 23,2055 72405 DMP SL1
014133,000174: 23,2056 00001 0
014134,000175: 23,2057 14045 STODL 36D # Z COMPONENT
014135,000176:
014136,000177: 23,2060 41356 SIN DMP
014137,000178: 23,2061 77752 SL1
014138,000179: 23,2062 24041 STOVL 32D
014139,000180: 23,2063 00041 32D
014140,000181: 23,2064 77616 RVQ
014141,000182:
014142,000183: # THIS ENTRY TO RRNB REQUIRES THE TRUNNION AND SHAFT ANGLES IN MPAC AND MPAC +1 RESPECTIVELY
014143,000184:
014144,000185: 23,2065 14025 RRNBMPAC STODL 20D # SAVE SHAFT CDU IN 21.
014145,000186: 23,2066 00155 MPAC # SET MODE TO DP. (THE PRECEEDING STORE
014146,000187: # MAY BE DP, TP OR VECTOR.)
014147,000188: 23,2067 40234 RTB SETPD
014148,000189: 23,2070 21577 CDULOGIC
014149,000190: 23,2071 00001 0
014150,000191: 23,2072 73406 PUSH SIN # TRUNNION ANGLE TO 0
014151,000192: 23,2073 77676 DCOMP
014152,000193: 23,2074 14043 STODL 34D # Y COMPONENT
014153,000194: 23,2075 41546 COS PUSH # .5COS(T) TO 0
014154,000195: 23,2076 47135 SLOAD RTB # PICK UP CDU'S.
014155,000196: 23,2077 00026 21D
014156,000197: 23,2100 21577 CDULOGIC
014157,000198: 23,2101 77650 GOTO
014158,000199: 23,2102 46054 RRNB1
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Page 330
Note: This page is empty in the printout of the assembly listing.
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End of include-file LEM_GEOMETRY.agc. Parent file is MAIN.agc