Source Code
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This is a reconstruction of the AGC program Luminary 99 Rev 0. It was the third release
of the Lunar Module flight software targeted for use in Apollo 11, after Luminary 96 and 97.
A bug (which had been around since at least Apollo 10, Luminary 69) was
discovered in Rev 0 shortly before the Apollo 11 flight, resulting in a last minute
revision into Rev 1,
which is what actually flew rather than
the Rev 0 presented here. A hardcopy of Rev 0 is known to
exist — it belonged to AGC developer Allan Klumpp for many years — but
unfortunately the Virtual AGC Project has not had access to that hardcopy. Thus
the code you see here had been reconstructed (we believe accurately) rather than
transcribed. The first step of the reconstruction of the Rev 0 source code was
the transcription of the Rev 1 source code from a hardcopy in the MIT Museum collection.
The process of reverting the active portion of the source code (i.e., other than
program comments) from Rev 1 to Rev 0 was very minor, consisting
only of moving the position of the STARTSB1 label in
FRESH START AND RESTART. Allan had previously given
us the checksums of the memory banks of Rev 0, and we have verified the program presented here has checksums
identical to all banks of Allan's listing of Rev 0. The notations on Allan's Rev 0 program listing read,
in part:GAP: ASSEMBLE REVISION 099 OF AGC PROGRAM LUMINARY BY NASA 2021112-051 A single program comment is known to differ between Rev 0 and Rev 1, but these are harder to reconstruct and verify than changes to the active portion of the code. Thus it is possible that there are additional differences between the program comments in Rev 0 and Rev 1 that are unknown to us, and therefore are not reflected in the code presented here. |
043635,000002: ## Copyright: Public domain.
043636,000003: ## Filename: LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc
043637,000004: ## Purpose: Part of the reconstructed source code for LMY99 Rev 0,
043638,000005: ## otherwise known as Luminary Rev 99, the third release
043639,000006: ## of the Apollo Guidance Computer (AGC) software for Apollo 11.
043640,000007: ## It differs from LMY99 Rev 1 (the flown version) only in the
043641,000008: ## placement of a single label. The corrections shown here have
043642,000009: ## been verified to have the same bank checksums as AGC developer
043643,000010: ## Allan Klumpp's copy of Luminary Rev 99, and so are believed
043644,000011: ## to be accurate. This file is intended to be a faithful
043645,000012: ## recreation, except that the code format has been changed to
043646,000013: ## conform to the requirements of the yaYUL assembler rather than
043647,000014: ## the original YUL assembler.
043648,000015: ##
043649,000016: ## Assembler: yaYUL
043650,000017: ## Contact: Hartmuth Gutsche <hgutsche@xplornet.com>.
043651,000018: ## Website: www.ibiblio.org/apollo.
043652,000019: ## Pages: 984-987
043653,000020: ## Mod history: 2009-05-24 HG Transcribed from page images.
043654,000021: ## 2016-12-17 RSB Proofed text comments with octopus/ProoferComments
043655,000022: ## and corrected the errors found.
043656,000023: ## 2017-03-13 RSB Comment-text fixes noted in proofing Luminary 116.
043657,000024: ## 2017-08-01 MAS Created from LMY99 Rev 1.
043658,000025: ## 2017-08-26 MAS Fixed comment-text errors found while transcribing Zerlina 56.
043659,000026:
043660,000027: ## This source code has been transcribed or otherwise adapted from
043661,000028: ## digitized images of a hardcopy from the MIT Museum. The digitization
043662,000029: ## was performed by Paul Fjeld, and arranged for by Deborah Douglas of
043663,000030: ## the Museum. Many thanks to both. The images (with suitable reduction
043664,000031: ## in storage size and consequent reduction in image quality as well) are
043665,000032: ## available online at www.ibiblio.org/apollo. If for some reason you
043666,000033: ## find that the images are illegible, contact me at info@sandroid.org
043667,000034: ## about getting access to the (much) higher-quality images which Paul
043668,000035: ## actually created.
043669,000036: ##
043670,000037: ## The code has been modified to match LMY99 Revision 0, otherwise
043671,000038: ## known as Luminary Revision 99, the Apollo 11 software release preceeding
043672,000039: ## the listing from which it was transcribed. It has been verified to
043673,000040: ## contain the same bank checksums as AGC developer Allan Klumpp's listing
043674,000041: ## of Luminary Revision 99 (for which we do not have scans).
043675,000042: ##
043676,000043: ## Notations on Allan Klumpp's listing read, in part:
043677,000044: ##
043678,000045: ## ASSEMBLE REVISION 099 OF AGC PROGRAM LUMINARY BY NASA 2021112-51
043679,000046:
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Page 984 |
043681,000048: # NAME - LSPOS - LOCATE SUN AND MOON DATE - 25 OCT 67
043682,000049: # MOD NO. 1
043683,000050: # MOD BY NEVILLE ASSEMBLY SUNDANCE
043684,000051:
043685,000052: # FUNCTIONAL DESCRIPTION
043686,000053:
043687,000054: # COMPUTES UNIT POSITION VECTOR OF THE SUN AND MOON IN THE BASIC REFERENCE SYSTEM. THE SUN VECTOR S IS
043688,000055: # LOCATED VIA TWO ANGLES. THE FIRST ANGLE(OBLIQUITY) IS THE ANGLE BETWEEN THE EARTH EQUATOR AND THE ECLIPTIC. THE
043689,000056: # SECOND ANGLE IS THE LONGITUDE OF THE SUN MEASURED IN THE ECLIPTIC.
043690,000057: # THE POSITION VECTOR OF THE SUN IS
043691,000058: # -
043692,000059: # S = (COS(LOS), COS(OBL)*SIN(LOS), SIN(OBL)*SIN(LOS)), WHERE
043693,000060:
043694,000061: # LOS = LOS +LOS *T-(C *SIN(2PI*T)/365.24 +C *COS(2PI*T)/365.24)
043695,000062: # 0 R 0 1
043696,000063: # LOS (RAD) IS THE LONGITUDE OF THE SUN FOR MIDNIGHT JUNE 30TH OF THE PARTICULAR YEAR.
043697,000064: # 0
043698,000065: # LOS (RAD/DAY) IS THE MEAN RATE FOR THE PARTICULAR YEAR.
043699,000066: # R
043700,000067:
043701,000068: # LOS AND LOS ARE STORED AS LOSC AND LOSR IN RATESP.
043702,000069: # 0 R
043703,000070: # COS(OBL) AND SIN(OBL) ARE STORED IN THE MATRIX KONMAT.
043704,000071:
043705,000072: # T, TIME MEASURED IN DAYS (24 HOURS), IS STORED IN TIMEP.
043706,000073:
043707,000074: # C AND C ARE FUDGE FACTORS TO MINIMIZE THE DEVIATION. THEY ARE STORED AS ONE CONSTANT (CMOD), SINCE
043708,000075: # 0 1 2 2 1/2
043709,000076: # C *SIN(X)+C *COS(X) CAN BE WRITTEN AS (C +C ) *SIN(X+PHI), WHERE PHI=ARCTAN(C /C ).
043710,000077: # 0 1 0 1 1 0
043711,000078:
043712,000079: # THE MOON IS LOCATED VIA FOUR ANGLES. THE FIRST IS THE OBLIQUITY. THE SECOND IS THE MEAN LONGITUDE OF THE MOON,
043713,000080: # MEASURED IN THE ECLIPTIC FROM THE MEAN EQUINOX TO THE MEAN ASCENDING NODE OF THE LUNAR ORBIT, AND THEN ALONG THE
043714,000081: # ORBIT. THE THIRD ANGLE IS THE ANGLE BETWEEN THE ECLIPTIC AND THE LUNAR ORBIT. THE FOURTH ANGLE IS THE LONGITUDE
043715,000082: # OF THE NODE OF THE MOON, MEASURED IN THE LUNAR ORBIT. LET THESE ANGLES BE OBL,LOM,IM, AND LON RESPECTIVELY.
043716,000083:
043717,000084: # THE SIMPLIFIED POSITION VECTOR OF THE MOON IS
043718,000085: # -
043719,000086: # M=(COS(LOM), COS(OBL)*SIN(LOM)-SIN(OBL)*SIN(IM)*SIN(LOM-LON), SIN(OBL)*SIN(LOM)+COS(OBL)*SIN(IM)*SIN(LOM-LON))
043720,000087:
043721,000088: # WHERE
043722,000089: # LOM=LOM +LOM *T-(A *SIN 2PI*T/27.5545+A *COS(2PI*T/27.5545)+B *SIN 2PI*T/32+B *COS(2PI*T/32)), AND
043723,000090: # 0 R 0 1 0 1
043724,000091: # LON=LON +LON
043725,000092: # 0 R
043726,000093: # A , A , B AND B ARE STORED AS AMOD AND BMOD (SEE DESCRIPTION OF CMOD, ABOVE). COS(OBL), SIN(OBL)*SIN(IM),
043727,000094: # 0 1 0 1
043728,000095: # SIN(OBL), AND COS(OBL)*SIN(IM) ARE STORED IN KONMAT AS K1, K2, K3 AND K4, RESPECTIVELY. LOM , LOM , LON , LON
043729,000096: # ARE STORED AS LOMO, LOMR, LONO, AND LONR IN RATESP. 0 R 0 R
043730,000097: # THE THREE PHIS ARE STORED AS AARG, BARG, AND CARG(SUN). ALL CONSTANTS ARE UPDATED BY YEAR.
043731,000098:
043732,000099: # CALLING SEQUENCE
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Page 985 |
043734,000101: # CALL LSPOS. RETURN IS VIA CPRET.
043735,000102:
043736,000103: # ALARMS OR ABORTS
043737,000104: # NONE
043738,000105:
043739,000106: # ERASABLE INITIALIZATION REQUIRED
043740,000107: # TEPHEM - TIME FROM MIDNIGHT 1 JULY PRECEDING THE LAUNCH TO THE TIME OF THE LAUNCH (WHEN THE AGC CLOCK WENT
043741,000108: # TO ZERO). TEPHEM IS TP WITH UNITS OF CENTI-SECONDS.
043742,000109:
043743,000110: # TIME2 AND TIME1 ARE IN MPAC AND MPAC +1 WHEN PROGRAM IS CALLED.
043744,000111:
043745,000112: # OUTPUT
043746,000113: # UNIT POSITIONAL VECTOR OF SUN IN VSUN. (SCALED B-1)
043747,000114: # UNIT POSITIONAL VECTOR OF MOON IN VMOON. (SCALED B-1)
043748,000115:
043749,000116: # SUBROUTINES USED
043750,000117: # NONE
043751,000118:
043752,000119: # DEBRIS
043753,000120: # CURRENT CORE SET, WORK AREA AND FREEFLAG
043754,000121:
043755,000122: 04,3027 BANK 04
043756,000123: 15,2000 SETLOC EPHEM
043757,000124: 15,2000 BANK
043758,000125:
043759,000126: 15,3664 E5,1714 EBANK= VSUN
043760,000127: 15,3664 COUNT* $$/EPHEM
043761,000128: 15,3664 15,3664 LUNPOS EQUALS LSPOS
043762,000129:
043763,000130: 15,3664 54201 LSPOS SETPD SR
043764,000131: 15,3665 00001 0
043765,000132: 15,3666 20617 14D # TP
043766,000133: 15,3667 56371 TAD DDV
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The hand-written notation "in centisec B 42" appears to the right. |
043768,000135: 15,3670 01707 TEPHEM # TIME OF LAUNCH
043769,000136: 15,3671 12024 CSTODAY # 24 HOURS-8640000 CENTI-SECS/DAY B-33
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The hand-written notation "@ B 9 = 512 days" appears to the right. |
043771,000138: 15,3672 00031 STORE TIMEP # T IN DAYS
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The hand-written notation "∴ granularity ≈ 0.164 sec" appears to the right. |
043773,000140: 15,3673 77170 AXT,1 AXT,2
043774,000141: 15,3674 00000 0
043775,000142: 15,3675 00000 0
043776,000143: 15,3676 77614 CLEAR
043777,000144: 15,3677 00274 FREEFLAG # SWITCH BIT
043778,000145: 15,3700 77745 POSITA DLOAD
043779,000146: 15,3701 12004 KONMAT +2 # ZEROS
043780,000147: 15,3702 00027 STORE GTMP
043781,000148: 15,3703 40745 POSITB DLOAD DMP*
043782,000149: 15,3704 00031 TIMEP # T
043783,000150: 15,3705 12050 VAL67 +4,1 # 1/27 OR 1/32 OR 1/365
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Page 986 |
043785,000152: 15,3706 42661 SL DAD*
043786,000153: 15,3707 20211 8D
043787,000154: 15,3710 12046 VAL67 +2,1 # AARG
043788,000155: 15,3711 40756 SIN DMP* # SIN(T/27+PHI) OR T/32 OR T/365
043789,000156: 15,3712 12044 VAL67,1 # (A0**2+A1**2)**1/2 SIN(X+PHIA)
043790,000157: 15,3713 62015 DAD INCR,1 # PLUS
043791,000158: 15,3714 00027 GTMP # (B0**2+B1**2)**1/2 SIN(X+PHIB)
043792,000159: 15,3715 77771 DEC -6 B-14
043793,000160: 15,3716 00027 STORE GTMP # OR (C0**2+C1**2)**1/2 SIN(X+PHIC)
043794,000161: 15,3717 77614 BOFSET
043795,000162: 15,3720 00054 FREEFLAG
043796,000163: 15,3721 33703 POSITB
043797,000164: 15,3722 40745 POSITD DLOAD DMP*
043798,000165: 15,3723 00031 TIMEP # T
043799,000166: 15,3724 65747 RATESP,2 # LOMR,LOSR,LONR
043800,000167: 15,3725 42661 SL DAD*
043801,000168: 15,3726 20206 5D
043802,000169: 15,3727 65741 RATESP +6,2 # LOMO,LOSO,LONO
043803,000170: 15,3730 77625 DSU
043804,000171: 15,3731 00027 GTMP
043805,000172: 15,3732 10021 STORE STMP,2 # LOM,LOS,LON
043806,000173: 15,3733 63135 SLOAD INCR,2
043807,000174: 15,3734 00050 X2
043808,000175: 15,3735 77775 DEC -2 B-14
043809,000176: 15,3736 53015 DAD BZE
043810,000177: 15,3737 12026 RCB-13 # PLUS 2
043811,000178: 15,3740 33770 POSITE # 2ND
043812,000179: 15,3741 77644 BPL
043813,000180: 15,3742 33700 POSITA # 1ST
043814,000181: 15,3743 45345 POSITF DLOAD DSU # 3RD
043815,000182: 15,3744 00021 STMP # LOM
043816,000183: 15,3745 00025 STMP +4 # LON
043817,000184: 15,3746 65356 SIN PDDL # SIN(LOM-LON)
043818,000185: 15,3747 00021 STMP
043819,000186: 15,3750 65356 SIN PDDL # SIN LOM
043820,000187: 15,3751 00021 STMP
043821,000188: 15,3752 55546 COS VDEF # COS LOM
043822,000189: 15,3753 53521 MXV UNIT
043823,000190: 15,3754 12002 KONMAT # K1,K2,K3,K4,
043824,000191: 15,3755 02723 STORE VMOON
043825,000192: 15,3756 65345 DLOAD PDDL
043826,000193: 15,3757 12004 KONMAT +2 # ZERO
043827,000194: 15,3760 00023 STMP +2
043828,000195: 15,3761 65356 SIN PDDL # SIN LOS
043829,000196: 15,3762 00023 STMP +2
043830,000197: 15,3763 55546 COS VDEF # COS LOS
043831,000198: 15,3764 53521 MXV UNIT
043832,000199: 15,3765 12002 KONMAT
043833,000200: 15,3766 02715 STORE VSUN
043834,000201: 15,3767 77616 RVQ
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Page 987 |
043836,000203: 15,3770 77745 POSITE DLOAD
043837,000204: 15,3771 12004 KONMAT +2 # ZEROS
043838,000205: 15,3772 00027 STORE GTMP
043839,000206: 15,3773 77650 GOTO
043840,000207: 15,3774 33722 POSITD
043841,000208: 15,3775 77616 LUNVEL RVQ # TO FOOL INTEGRATION
043842,000209: 05,2000 SETLOC EPHEM1
043843,000210: 05,2000 BANK
043844,000211:
043845,000212: 05,3506 COUNT* $$/EPHEM
043846,000213: 05,3506 STMP EQUALS 16D
043847,000214: 05,3506 GTMP EQUALS 22D
043848,000215: 05,3506 TIMEP EQUALS 24D
043849,000216:
End of include-file LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc. Parent file is MAIN.agc