Source Code
|
These source-code files are part of a reconstructed copy of Artemis 071, the
first release of the Apollo 15 through 17 Command Module (CM) Apollo Guidance
Computer (AGC) software.
The reconstruction began with source code of Artemis 072 previously transcribed
from a digitized copy of that program. The code was then updated by undoing
changes between the two versions. The reconstruction was verified by matching
memory-bank checksums to those listed in drawing 2021154-. Note that page
numbers in the reconstructed code match those on the Artemis 072 printout,
although the changed code would likely have changed page numbers for a real
Artemis 071 listing.
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.
|
034976,000002: ## Copyright: Public domain.
034977,000003: ## Filename: LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc
034978,000004: ## Purpose: A section of Artemis revision 071.
034979,000005: ## It is part of the reconstructed source code for the first
034980,000006: ## release of the flight software for the Command Module's
034981,000007: ## (CM) Apollo Guidance Computer (AGC) for Apollo 15 through
034982,000008: ## 17. The code has been recreated from a copy of Artemis 072.
034983,000009: ## It has been adapted such that the resulting bugger words
034984,000010: ## exactly match those specified for Artemis 071 in NASA
034985,000011: ## drawing 2021154-, which gives relatively high confidence
034986,000012: ## that the reconstruction is correct.
034987,000013: ## Reference: 789
034988,000014: ## Assembler: yaYUL
034989,000015: ## Contact: Ron Burkey <info@sandroid.org>.
034990,000016: ## Website: www.ibiblio.org/apollo/index.html
034991,000017: ## Mod history: 2019-08-14 MAS Created from Artemis 072.
034992,000018:
|
|
Page 789
|
034994,000020:
034995,000021: # LUNAR AND SOLAR EPHEMERIDES SUBROUTINES
034996,000022:
034997,000023: # FUNCTIONAL DESCRIPTION
034998,000024:
034999,000025: # THESE SUBROUTINES ARE USED TO DETERMINE THE POSITION AND VELOCITY
035000,000026: # VECTORS OF THE SUN AND THE MOON RELATIVE TO THE EARTH AT THE
035001,000027: # SPECIFIED GROUND ELAPSED TIME INPUT BY THE USER.
035002,000028:
035003,000029: # THE POSITION OF THE MOON IS STORED IN THE COMPUTER IN THE FORM OF
035004,000030: # A NINTH DEGREE POLYNOMIAL APPROXIMATION WHICH IS VALID OVER A 15
035005,000031: # DAY INTERVAL BEGINNING SHORTLY BEFORE LAUNCH. THEREFORE THE TIME
035006,000032: # INPUT BY THE USER SHOULD FALL WITHIN THIS 15 DAY INTERVAL.
035007,000033: #
|
|
The 9th-degree polynomial spoken of here is a pad load, meaning
that it is not actually hardcoded into the software. Additional
information about calculating the polynomial can be found on the
Orbiter NASSP wiki, as well as information about calculation
of the
solar ephemerides.
|
035015,000041:
035016,000042: # LSPOS COMPUTES THE POSITION VECTORS OF THE SUN AND THE MOON.
035017,000043:
035018,000044: # LUNPOS COMPUTES THE POSITION VECTOR OF THE MOON.
035019,000045:
035020,000046: # LUNVEL COMPUTES THE VELOCITY VECTOR OF THE MOON.
035021,000047:
035022,000048: # CALLING SEQUENCE
035023,000049:
035024,000050: # DLOAD CALL
035025,000051: # TIME GROUND ELAPSED TIME
035026,000052: # SUBROUTINE LSPOS OR LUNPOS OR LUNVEL
035027,000053:
035028,000054: # INPUT
035029,000055:
035030,000056: # 1) SPECIFIED GROUND ELAPSED TIME IN CS X B-28 LOADED IN MPAC.
035031,000057:
035032,000058: # 2) TIMEMO - TIME AT THE CENTER OF THE RANGE OVER WHICH THE LUNAR
035033,000059: # POSITION POLYNOMIAL IS VALID IN CS X B-42.
035034,000060:
035035,000061: # 3) VECOEM - VECTOR COEFFICIENTS OF THE LUNAR POSITION POLYNOMIAL
035036,000062: # LOADED IN DESCENDING SEQUENCE IN METERS/CS**N X B-2
035037,000063:
035038,000064: # 4) RESO - POSITION VECTOR OF THE SUN RELATIVE TO THE EARTH AT
035039,000065: # TIMEMO IN METERS X B-38.
035040,000066:
035041,000067: # 5) VESO - VELOCITY VECTOR OF THE SUN RELATIVE TO THE EARTH AT
035042,000068: # TIMEMO IN METERS/CS X B-9.
035043,000069: #
035044,000070: # 6) OMEGAES - ANGULAR VELOCITY OF THE VECTOR RESO AT TIMEMO IN
035045,000071: # REV/CS X B+26.
035046,000072:
035047,000073: # ALL EXCEPT THE FIRST INPUT ARE INCLUDED IN THE PRE-LAUNCH
035048,000074: # ERASABLE DATA LOAD.
035049,000075:
035050,000076: # OUTPUT - LSPOS
035051,000077:
035052,000078: # 1) 2D OF VAC AREA CONTAINS THE POSITION VECTOR OF THE SUN RELATIVE
|
|
Page 790
|
035054,000080: # TO THE EARTH AT TIME INPUT BY THE USER IN METERS X B-38.
035055,000081:
035056,000082: # 2) MPAC CONTAINS THE POSITION VECTOR OF THE MOON RELATIVE TO THE
035057,000083: # EARTH AT TIME INPUT BY THE USER IN METERS X B-29.
035058,000084:
035059,000085: # OUTPUT - LUNPOS
035060,000086:
035061,000087: # MPAC CONTAINS THE POSITION VECTOR OF THE MOON RELATIVE TO THE
035062,000088: # EARTH AT THE TIME INPUT BY USER IN METERS X B-29.
035063,000089:
035064,000090: # OUTPUT - LUNVEL
035065,000091:
035066,000092: # MPAC CONTAINS THE VELOCITY VECTOR OF THE MOON RELATIVE TO THE
035067,000093: # EARTH AT TIME INPUT BY THE USER IN METERS/CS X B-7.
035068,000094:
035069,000095: # SUBROUTINES USED
035070,000096:
035071,000097: # NONE
035072,000098:
035073,000099: # REMARKS
035074,000100:
035075,000101: # THE VAC AREA IS USED FOR STORAGE OF INTERMEDIATE AND FINAL RESULTS
035076,000102: # OF COMPUTATIONS.
035077,000103:
035078,000104: # S1, X1 AND X2 ARE USED BY THESE SUBROUTINES.
035079,000105: # PRELAUNCH ERASABLE DATA LOAD ARE ONLY ERASABLE STORAGE USED BY
035080,000106: # THESE SUBROUTINES.
035081,000107: # RESTARTS DURING OPERATION OF THESE SUBROUTINES MUST BE HANDLED BY
035082,000108: # THE USER.
035083,000109:
035084,000110: 26,2000 SETLOC EPHEM
035085,000111: 26,2000 BANK
035086,000112:
035087,000113: 26,2136 COUNT* $$/EPHEM
035088,000114: 26,2136 0003777 EBANK= WHOCARES
035089,000115: 26,2136 52170 LSPOS AXT,1 GOTO
035090,000116: 26,2137 54163 RES # AREA. THE POSITION VECTOR OF THE MOON
035091,000117: 26,2140 54146 LSTIME # IS STORED IN MPAC.
035092,000118: 26,2141 52170 LUNPOS AXT,1 GOTO # COMPUTES THE POSITION VECTOR OF THE MOON
035093,000119: 26,2142 54201 REM # AND STORES IT IN MPAC.
035094,000120: 26,2143 54146 LSTIME
035095,000121: 26,2144 77770 LUNVEL AXT,1
035096,000122: 26,2145 54212 VEM # AND STORES IT IN MPAC.
035097,000123: 26,2146 54201 LSTIME SETPD SR
035098,000124: 26,2147 00001 0D
035099,000125: 26,2150 20617 14D
035100,000126: 26,2151 57571 TAD DCOMP
035101,000127: 26,2152 01707 TEPHEM
035102,000128: 26,2153 57571 TAD DCOMP
035103,000129: 26,2154 02034 TIMEMO
|
|
Page 791
|
035105,000131: 26,2155 66261 SL SSP
035106,000132: 26,2156 20221 16D
035107,000133: 26,2157 00051 S1
035108,000134: 26,2160 00006 6D
035109,000135: 26,2161 77650 GOTO
035110,000136: 26,2162 00046 X1
035111,000137: 26,2163 41206 RES PUSH DMP # PD- 2
035112,000138: 26,2164 02147 OMEGAES
035113,000139: 26,2165 71406 PUSH COS # PD- 4
035114,000140: 26,2166 65361 VXSC PDDL # PD- 8
035115,000141: 26,2167 02133 RESO
035116,000142: 26,2170 63356 SIN PDVL # PD-10
035117,000143: 26,2171 02133 RESO
035118,000144: 26,2172 53406 PUSH UNIT # PD-16
035119,000145: 26,2173 53435 VXV UNIT
035120,000146: 26,2174 02141 VESO
035121,000147: 26,2175 76435 VXV VSL1 # PD-10
035122,000148: 26,2176 53361 VXSC VAD # PD-02
035123,000149: 26,2177 77772 VSL1
035124,000150: 26,2200 14003 RESA STODL 2D # RES IN METERS X B-38 IN 2D OF VAC. PD- 0
035125,000151: 26,2201 63370 REM AXT,1 PDVL # PD- 2
035126,000152: 26,2202 00066 54D
035127,000153: 26,2203 02037 VECOEM
035128,000154: 26,2204 52761 REMA VXSC VAD*
035129,000155: 26,2205 00001 0D
035130,000156: 26,2206 02133 VECOEM +60D,1
035131,000157: 26,2207 72500 TIX,1 VSL2 # REM IN METERS X B-29 IN MPAC.
035132,000158: 26,2210 54204 REMA
035133,000159: 26,2211 77616 RVQ
035134,000160: 26,2212 65370 VEM AXT,1 PDDL # PD- 2
035135,000161: 26,2213 00060 48D
035136,000162: 26,2214 14233 NINEB4
035137,000163: 26,2215 74206 PUSH VXSC # PD- 4
035138,000164: 26,2216 02037 VECOEM
035139,000165: 26,2217 77761 VEMA VXSC
035140,000166: 26,2220 00001 0D
035141,000167: 26,2221 14005 STODL 4D # PD- 2
035142,000168: 26,2222 41425 DSU PUSH # PD- 4
035143,000169: 26,2223 31771 ONEB4
035144,000170: 26,2224 53357 VXSC* VAD
035145,000171: 26,2225 02125 VECOEM +54D,1
035146,000172: 26,2226 00005 4D
035147,000173: 26,2227 72500 TIX,1 VSL2 # VEM IN METERS/CS X B-7 IN MPAC.
035148,000174: 26,2230 54217 VEMA
035149,000175: 26,2231 77616 RVQ
035150,000176: 26,2232 22000 00000 NINEB4 2DEC 9.0 B-4
035151,000177: 26,2234 34,3770 ONEB4 EQUALS DP2(-4) # 1 B-4
035152,000178:
End of include-file LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc. Parent file is MAIN.agc