Source Code
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These source-code files are part of a reconstructed copy of Comanche 72/3 (AKA Manche72 revision 3),
the final, flown mission release of the Apollo Guidance Computer (AGC) Command Module (CM) software
for Apollo 13.
The starting point was the source code of Comanche 72 (itself previously reconstructed). Comanche 72
source code was then modified by incorporating changes known from contemporary documentation to have
been made between revisions 72 and 72/3. The resulting code assembles to have identical
memory-bank checksums as those specified in NASA drawing 2021153G; this gives reasonably
high confidence that the changes that have been made are correct. In places where
ambiguity exists, this ambiguity is discussed in "## Reconstruction:" comments.
Since no contemporary listings of Comanche 72/3 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.
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033779,000002: ## Copyright: Public domain.
033780,000003: ## Filename: LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc
033781,000004: ## Purpose: A section of Manche72 revision 3.
033782,000005: ## It is part of the reconstructed source code for the final, flown
033783,000006: ## release of the software for the Command Module's (CM) Apollo
033784,000007: ## Guidance Computer (AGC) for Apollo 13. No original listings
033785,000008: ## of this program are available; instead, this file was recreated
033786,000009: ## from a reconstructed copy of Comanche 072. It has been adapted
033787,000010: ## such that the resulting bugger words exactly match those
033788,000011: ## specified for Manche72 revision 3 in NASA drawing 2021153G,
033789,000012: ## which gives relatively high confidence that the reconstruction
033790,000013: ## is correct.
033791,000014: ## Assembler: yaYUL
033792,000015: ## Contact: Ron Burkey <info@sandroid.org>.
033793,000016: ## Website: www.ibiblio.org/apollo/index.html
033794,000017: ## Mod history: 2024-05-19 MAS Created from Comanche 072.
033795,000018:
033796,000019: # LUNAR AND SOLAR EPHEMERIDES SUBROUTINES
033797,000020:
033798,000021: # FUNCTIONAL DESCRIPTION
033799,000022:
033800,000023: # THESE SUBROUTINES ARE USED TO DETERMINE THE POSITION AND VELOCITY
033801,000024: # VECTORS OF THE SUN AND THE MOON RELATIVE TO THE EARTH AT THE
033802,000025: # SPECIFIED GROUND ELAPSED TIME INPUT BY THE USER.
033803,000026:
033804,000027: # THE POSITION OF THE MOON IS STORED IN THE COMPUTER IN THE FORM OF
033805,000028: # A NINTH DEGREE POLYNOMIAL APPROXIMATION WHICH IS VALID OVER A 15
033806,000029: # DAY INTERVAL BEGINNING SHORTLY BEFORE LAUNCH. THEREFORE THE TIME
033807,000030: # INPUT BY THE USER SHOULD FALL WITHIN THIS 15 DAY INTERVAL.
033808,000031:
033809,000032: # LSPOS COMPUTES THE POSITION VECTORS OF THE SUN AND THE MOON.
033810,000033:
033811,000034: # LUNPOS COMPUTES THE POSITION VECTOR OF THE MOON.
033812,000035:
033813,000036: # LUNVEL COMPUTES THE VELOCITY VECTOR OF THE MOON.
033814,000037:
033815,000038: # SOLPOS COMPUTES THE POSITION VECTOR OF THE SUN.
033816,000039:
033817,000040: # CALLING SEQUENCE
033818,000041:
033819,000042: # DLOAD CALL
033820,000043: # TIME GROUND ELAPSED TIME
033821,000044: # SUBROUTINE LSPOS OR LUNPOS OR LUNVEL OR SOLPOS
033822,000045:
033823,000046: # INPUT
033824,000047:
033825,000048: # 1) SPECIFIED GROUND ELAPSED TIME IN CS X B-28 LOADED IN MPAC.
033826,000049:
033827,000050: # 2) TIMEMO - TIME AT THE CENTER OF THE RANGE OVER WHICH THE LUNAR
033828,000051: # POSITION POLYNOMIAL IS VALID IN CS X B-42.
033829,000052:
033830,000053: # 3) VECOEM - VECTOR COEFFICIENTS OF THE LUNAR POSITION POLYNOMIAL
033831,000054: # LOADED IN DESCENDING SEQUENCE IN METERS/CS**N X B-2
033832,000055:
033833,000056: # 4) RESO - POSITION VECTOR OF THE SUN RELATIVE TO THE EARTH AT
033834,000057: # TIMEMO IN METERS X B-38.
033835,000058:
033836,000059: # 5) VESO - VELOCITY VECTOR OF THE SUN RELATIVE TO THE EARTH AT
033837,000060: # TIMEMO IN METERS/CS X B-9.
033838,000061: #
033839,000062: # 6) OMEGAES - ANGULAR VELOCITY OF THE VECTOR RESO AT TIMEMO IN
033840,000063: # REV/CS X B+26.
033841,000064:
033842,000065: # ALL EXCEPT THE FIRST INPUT ARE INCLUDED IN THE PRE-LAUNCH
033843,000066: # ERASABLE DATA LOAD.
033844,000067:
033845,000068: # OUTPUT - LSPOS
033846,000069:
033847,000070: # 1) 2D OF VAC AREA CONTAINS THE POSITION VECTOR OF THE SUN RELATIVE
033848,000071: # TO THE EARTH AT TIME INPUT BY THE USER IN METERS X B-38.
033849,000072:
033850,000073: # 2) MPAC CONTAINS THE POSITION VECTOR OF THE MOON RELATIVE TO THE
033851,000074: # EARTH AT TIME INPUT BY THE USER IN METERS X B-29.
033852,000075:
033853,000076: # OUTPUT - LUNPOS
033854,000077:
033855,000078: # MPAC CONTAINS THE POSITION VECTOR OF THE MOON RELATIVE TO THE
033856,000079: # EARTH AT THE TIME INPUT BY USER IN METERS X B-29.
033857,000080:
033858,000081: # OUTPUT - LUNVEL
033859,000082:
033860,000083: # MPAC CONTAINS THE VELOCITY VECTOR OF THE MOON RELATIVE TO THE
033861,000084: # EARTH AT TIME INPUT BY THE USER IN METERS/CS X B-7.
033862,000085:
033863,000086: # OUTPUT - SOLPOS
033864,000087:
033865,000088: # MPAC CONTAINS THE POSITION VECTOR OF THE SUN RELATIVE TO THE EARTH
033866,000089: # AT TIME INPUT BY THE USER IN METERS X B-38.
033867,000090:
033868,000091: # SUBROUTINES USED
033869,000092:
033870,000093: # NONE
033871,000094:
033872,000095: # REMARKS
033873,000096:
033874,000097: # THE VAC AREA IS USED FOR STORAGE OF INTERMEDIATE AND FINAL RESULTS
033875,000098: # OF COMPUTATIONS.
033876,000099:
033877,000100: # S1, X1 AND X2 ARE USED BY THESE SUBROUTINES.
033878,000101:
033879,000102: # PRELAUNCH ERASABLE DATA LOAD ARE ONLY ERASABLE STORAGE USED BY
033880,000103: # THESE SUBROUTINES.
033881,000104:
033882,000105: # RESTARTS DURING OPERATION OF THESE SUBROUTINES MUST BE HANDLED BY
033883,000106: # THE USER.
033884,000107:
033885,000108: 36,2466 BANK 36
033886,000109: 26,2000 SETLOC EPHEM
033887,000110: 26,2000 BANK
033888,000111:
033889,000112: 26,2110 COUNT* $$/EPHEM
033890,000113: 26,2110 E7,1777 EBANK= END-E7
033891,000114: 26,2110 77774 LSPOS AXT,2 # COMPUTES POSITION VECTORS OF BOTH THE
033892,000115: 26,2111 54161 RESA # SUN AND THE MOON. THE POSITION VECTOR
033893,000116: 26,2112 52170 AXT,1 GOTO # OF THE SUN IS STORED IN 2D OF THE VAC
033894,000117: 26,2113 54143 RES # AREA. THE POSITION VECTOR OF THE MOON
033895,000118: 26,2114 54126 LSTIME # IS STORED IN MPAC.
033896,000119: 26,2115 52170 LUNPOS AXT,1 GOTO # COMPUTES THE POSITION VECTOR OF THE MOON
033897,000120: 26,2116 54162 REM # AND STORES IT IN MPAC.
033898,000121: 26,2117 54126 LSTIME
033899,000122: 26,2120 52170 LUNVEL AXT,1 GOTO # COMPUTES THE VELOCITY VECTOR OF THE MOON
033900,000123: 26,2121 54173 VEM # AND STORES IT IN MPAC.
033901,000124: 26,2122 54126 LSTIME
033902,000125: 26,2123 76020 SOLPOS STQ AXT,1 # COMPUTES THE POSITION VECTOR OF THE SUN
033903,000126: 26,2124 00047 X2 # AND STORES IT IN MPAC.
033904,000127: 26,2125 54143 RES
033905,000128: 26,2126 54201 LSTIME SETPD SR
033906,000129: 26,2127 00001 0D
033907,000130: 26,2130 20617 14D
033908,000131: 26,2131 57571 TAD DCOMP
033909,000132: 26,2132 01707 TEPHEM
033910,000133: 26,2133 57571 TAD DCOMP
033911,000134: 26,2134 02034 TIMEMO
033912,000135: 26,2135 66261 SL SSP
033913,000136: 26,2136 20221 16D
033914,000137: 26,2137 00051 S1
033915,000138: 26,2140 00006 6D
033916,000139: 26,2141 77650 GOTO
033917,000140: 26,2142 00046 X1
033918,000141: 26,2143 41206 RES PUSH DMP # PD- 2
033919,000142: 26,2144 02147 OMEGAES
033920,000143: 26,2145 71406 PUSH COS # PD- 4
033921,000144: 26,2146 65361 VXSC PDDL # PD- 8
033922,000145: 26,2147 02133 RESO
033923,000146: 26,2150 63356 SIN PDVL # PD-10
033924,000147: 26,2151 02133 RESO
033925,000148: 26,2152 53406 PUSH UNIT # PD-16
033926,000149: 26,2153 53435 VXV UNIT
033927,000150: 26,2154 02141 VESO
033928,000151: 26,2155 76435 VXV VSL1 # PD-10
033929,000152: 26,2156 53361 VXSC VAD # PD-02
033930,000153: 26,2157 52172 VSL1 GOTO # RES IN METERS X B-38 IN MPAC.
033931,000154: 26,2160 00047 X2
033932,000155: 26,2161 14003 RESA STODL 2D # RES IN METERS X B-38 IN 2D OF VAC. PD- 0
033933,000156: 26,2162 63370 REM AXT,1 PDVL # PD- 2
033934,000157: 26,2163 00066 54D
033935,000158: 26,2164 02037 VECOEM
033936,000159: 26,2165 52761 REMA VXSC VAD*
033937,000160: 26,2166 00001 0D
033938,000161: 26,2167 02133 VECOEM +60D,1
033939,000162: 26,2170 72500 TIX,1 VSL2 # REM IN METERS X B-29 IN MPAC.
033940,000163: 26,2171 54165 REMA
033941,000164: 26,2172 77616 RVQ
033942,000165: 26,2173 65370 VEM AXT,1 PDDL # PD- 2
033943,000166: 26,2174 00060 48D
033944,000167: 26,2175 14214 NINEB4
033945,000168: 26,2176 74206 PUSH VXSC # PD- 4
033946,000169: 26,2177 02037 VECOEM
033947,000170: 26,2200 77761 VEMA VXSC
033948,000171: 26,2201 00001 0D
033949,000172: 26,2202 14005 STODL 4D # PD- 2
033950,000173: 26,2203 41425 DSU PUSH # PD- 4
033951,000174: 26,2204 14216 ONEB4
033952,000175: 26,2205 53357 VXSC* VAD
033953,000176: 26,2206 02125 VECOEM +54D,1
033954,000177: 26,2207 00005 4D
033955,000178: 26,2210 72500 TIX,1 VSL2 # VEM IN METERS/CS X B-7 IN MPAC.
033956,000179: 26,2211 54200 VEMA
033957,000180: 26,2212 77616 RVQ
033958,000181: 26,2213 22000 00000 NINEB4 2DEC 9.0 B-4
033959,000182:
033960,000183: 26,2215 02000 00000 ONEB4 2DEC 1.0 B-4
033961,000184:
033962,000185:
033963,000186:
End of include-file LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc. Parent file is MAIN.agc