Source Code
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These source-code files are part of a reconstructed copy of Luminary 97, the
second release of the Apollo 11 Lunar Module (LM) Apollo Guidance Computer
(AGC) software. It was created to fix two incorrect ephemeris constants in
Luminary 96, as described by anomaly report LNY-59.
The reconstruction began with source code of Luminary 99 revision 1 previously
transcribed from a digitized copy of that program. The code was then updated
by undoing changes described in original Luminary memos 83 and 85, using asterisks
indicating changed lines in the listing as a guide. The reconstruction was
verified by matching memory-bank checksums to those listed in drawing 2021152D.
Note that page numbers in the reconstructed code match those on the Luminary 099
revision 001 printout, although the added code would likely have changed page
numbers for a real Luminary 97 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.
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064214,000002: ## Copyright: Public domain.
064215,000003: ## Filename: SPS_BACK-UP_RCS_CONTROL.agc
064216,000004: ## Purpose: A section of Luminary revision 97.
064217,000005: ## It is part of the reconstructed source code for the
064218,000006: ## second release of the flight software for the Lunar
064219,000007: ## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 11.
064220,000008: ## It was created to fix two incorrect ephemeris constants in
064221,000009: ## Luminary 96, as described by anomaly report LNY-59.
064222,000010: ## The code has been recreated from a copy of Luminary 99
064223,000011: ## revision 001, using asterisks indicating changed lines in
064224,000012: ## the listing and Luminary Memos #83 and #85, which list
064225,000013: ## changes between Luminary 97 and 98, and 98 and 99. The
064226,000014: ## code has been adapted such that the resulting bugger words
064227,000015: ## exactly match those specified for Luminary 97 in NASA drawing
064228,000016: ## 2021152D, which gives relatively high confidence that the
064229,000017: ## reconstruction is correct.
064230,000018: ## Reference: pp. 1507-1510
064231,000019: ## Assembler: yaYUL
064232,000020: ## Contact: Ron Burkey <info@sandroid.org>.
064233,000021: ## Website: www.ibiblio.org/apollo/index.html
064234,000022: ## Mod history: 2019-07-28 MAS Created from Luminary 99.
064235,000023:
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Page 1507
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064237,000025: # PROGRAM NAME: SPSRCS
064238,000026: # AUTHOR: EDGAR M. OSHIKA (AC ELECTRONICS)
064239,000027: # MODIFIED: TO RETURN TO ALL AXES VIA Q BY P. S. WEISSMAN, OCT 7, 1968
064240,000028: # MODIFIED TO IMPROVE BENDING STABILITY BY G. KALAN, FEB. 14, 1969
064241,000029:
064242,000030: # FUNCTIONAL DESCRIPTION:
064243,000031: # THIS PROGRAM CONTROLS THE FIRING OF ALL RCS JETS IN THE DOCKED CONFIGURATION ACCORDING TO THE FOLLOWING PHASE
064244,000032: # PLANE LOGIC.
064245,000033:
064246,000034: # 1. JET SENSE TEST (SPSRCS)
064247,000035: # IF JETS ARE FIRING NEGATIVELY, SET OLDSENSE NEGATIVE AND CONTINUE
064248,000036: # IF JETS ARE FIRING POSITIVELY, SET OLDSENSE POSITIVE AND CONTINUE
064249,000037: # IF JETS ARE NOT FIRING, SET OLDSENSE TO ZERO AND GO TO OUTER RATE LIMIT TEST
064250,000038:
064251,000039: # 2. RATE DEAD BAND TEST
064252,000040: # IF JETS ARE FIRING NEGATIVELY AND RATE IS GREATER THAN TARGET RATE, LEAVE
064253,000041: # JETS ON AND GO TO INHIBITION LOGIC. OTHERWISE, CONTINUE.
064254,000042: # IF JETS ARE FIRING POSITIVELY AND RATE IS LESS THAN TARGET RATE, LEAVE
064255,000043: # JETS ON AND GO TO INHIBITION LOGIC. OTHERWISE, CONTINUE.
064256,000044:
064257,000045: # 3. OUTER RATE LIMIT TEST (SPSSTART)
064258,000046: # IF MAGNITUDE OF EDOT IS GREATER THAN 1.73 DEG/SEC SET JET FIRING TIME
064259,000047: # TO REDUCE RATE AND GO TO INHIBITION LOGIC. OTHERWISE, CONTINUE.
064260,000048:
064261,000049: # 4. COAST ZONE TEST
064262,000050: # IF STATE (E,EDOT) IS BELOW LINE E + 4 X EDOT > -1.4 DEG AND EDOT IS LESS THAN 1.30 DEG/SEC SET JET TIME POSI-
064263,000051: # TIVE AND CONTINUE. OTHERWISE, SET JET FIRING TIME TO ZERO AND CONTINUE.
064264,000052: # IF STATE IS ABOVE LINE E + 4 X EDOT > +1.4 DEG AND EDOT IS GREATER THAN -1.30 DEG/SEC, SET JET TIME NEGATIVE
064265,000053: # AND CONTINUE. OTHERWISE, SET JET FIRING TIME TO ZERO AND CONTINUE.
064266,000054:
064267,000055: # 5. INHIBITION LOGIC
064268,000056: # IF OLDSENSE IS NON-ZERO:
064269,000057: # A) RETURN IF JET TIME HAS SAME SIGN AS OLDSENSE
064270,000058: # B) SET INHIBITION COUNTER* AND RETURN IF JET TIME IS ZERO
064271,000059: # C) SET INHIBITION COUNTER,* SET JET TIME TO ZERO AND RETURN IF SIGN
064272,000060: # OF JET TIME IS OPPOSITE TO THAT OF OLDSENSE
064273,000061: # IF OLDSENSE IS ZERO:
064274,000062: # A) RETURN IF INHIBITION COUNTER IS NOT POSITIVE
064275,000063: # B) SET JET TIME TO ZERO AND RETURN IF INHIBITION COUNTER IS POSITIVE
064276,000064: # *NOTE: INHIBITION COUNTERS CAN BE SET TO 4 OR 10 FOR THE P, AND UV AXES,
064277,000065: # RESPECTIVELY, IN SPSRCS. THEY ARE DECREMENTED BY ONE AT THE BEGINNING OF
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Page 1508
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064279,000067: # EACH DAP PASS.
064280,000068:
064281,000069: # THE MINIMUM PULSE WIDTH OF THIS CONTROLLER IS DETERMINED BY THE REPETITION RATE AT WHICH THIS ROUTINE IS CALLED
064282,000070: # AND IS NOMINALLY 100 MS FOR ALL AXES IN DRIFTING FLIGHT. DURING POWERED FLIGHT THE MINIMUM IS 100 MS FOR THE
064283,000071: # P AXIS AND 200 MS FOR THE CONTROL OF THE U AND V AXES.
064284,000072:
064285,000073: # CALLING SEQUENCE:
064286,000074: # INHINT
064287,000075: # TC IBNKCALL
064288,000076: # CADR SPSRCS
064289,000077:
064290,000078: # EXIT:
064291,000079: # TC Q
064292,000080:
064293,000081: # ALARM/ABORT MODE: NONE
064294,000082:
064295,000083: # SUBROUTINES CALLED: NONE
064296,000084:
064297,000085: # INPUT: E, EDOT
064298,000086: # TJP, TJV, TJU TJ MUST NOT BE NEGATIVE ZERO
064299,000087:
064300,000088: # OUTPUT: TJP, TJV, TJU
064301,000089:
064302,000090: 21,3646 BANK 21
064303,000091: 21,2000 SETLOC DAPS4
064304,000092: 21,2000 BANK
064305,000093:
064306,000094: 21,3646 COUNT* $$/DAPBU
064307,000095:
064308,000096: 21,3646 E6,1525 EBANK= TJU
064309,000097: 21,3646 00632 RATELIM2 OCT 00632 # 1.125 DEG/SEC
064310,000098: 21,3647 34736 POSTHRST CA HALF
064311,000099:
064312,000100: 21,3650 51505 NDX AXISCTR
064313,000101: 21,3651 55525 TS TJU
064314,000102: 21,3652 11745 CCS OLDSENSE
064315,000103: 21,3653 13673 TCF POSCHECK # JETS FIRING POSITIVELY
064316,000104: 21,3654 13676 TCF CTRCHECK # JETS OFF. CHECK INHIBITION CTR
064317,000105: 21,3655 51505 NEGCHECK INDEX AXISCTR # JETS FIRING NEGATIVELY
064318,000106: 21,3656 41525 CS TJU
064319,000107: 21,3657 10000 CCS A
064320,000108: 21,3660 00002 TC Q # RETURN
064321,000109: 21,3661 13663 TCF +2
064322,000110: 21,3662 13663 TCF +1 # JETS COMMANDED OFF. SET CTR AND RETURN
064323,000111: 21,3663 51505 SETCTR INDEX AXISCTR # JET FIRING REVERSAL COMMANDED. SET CTR,
064324,000112: 21,3664 33705 CA UTIME # SET JET TIME TO ZERO, AND RETURN
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Page 1509
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064326,000114: 21,3665 51505 INDEX AXISCTR
064327,000115: 21,3666 55770 TS UJETCTR
064328,000116: 21,3667 34755 ZAPTJ CA ZERO
064329,000117: 21,3670 51505 INDEX AXISCTR
064330,000118: 21,3671 55525 TS TJU
064331,000119: 21,3672 00002 TC Q
064332,000120: 21,3673 51505 POSCHECK INDEX AXISCTR
064333,000121: 21,3674 31525 CA TJU
064334,000122: 21,3675 13657 TCF NEGCHECK +2
064335,000123: 21,3676 51505 CTRCHECK INDEX AXISCTR # CHECK JET INHIBITION COUNTER
064336,000124: 21,3677 11770 CCS UJETCTR
064337,000125: 21,3700 13702 TCF +2
064338,000126: 21,3701 00002 TC Q # CTR IS NOT POSITIVE. RETURN
064339,000127: 21,3702 13667 TCF ZAPTJ # CTR IS POSITIVE. INHIBIT FIRINGS
064340,000128: 21,3703 00002 TC Q # CTR IS NOT POSITIVE. RETURN
064341,000129: 21,3704 00004 OCT 00004
064342,000130: 21,3705 00012 UTIME OCT 00012
064343,000131: 21,3706 00012 OCT 00012
064344,000132: 21,3707 E6,1745 OLDSENSE EQUALS DAPTREG1
064345,000133: 21,3707 44753 NEGFIRE CS ONE # JETS FIRING NEGATIVELY
064346,000134: 21,3710 55745 TS OLDSENSE
064347,000135: 21,3711 31427 CA EDOT
064348,000136: 21,3712 13716 TCF +4
064349,000137: 21,3713 34753 PLUSFIRE CA ONE
064350,000138: 21,3714 55745 TS OLDSENSE
064351,000139: 21,3715 41427 CS EDOT # RATE DEAD BAND TEST
064352,000140: 21,3716 22000 LXCH A
064353,000141: 21,3717 40111 CS DAPBOOLS # IF DRIFTBIT = 1, USE ZERO TARGET RATE
064354,000142: 21,3720 74744 MASK DRIFTBIT # IF DRIFTBIT = 0, USE 0.10 RATE TARGET
064355,000143: 21,3721 10000 CCS A
064356,000144: 21,3722 34767 CA RATEDB1
064357,000145: 21,3723 60001 AD L
064358,000146: 21,3724 00006 EXTEND
064359,000147: 21,3725 63735 BZMF SPSSTART
064360,000148: 21,3726 13652 TCF POSTHRST +3
064361,000149:
064362,000150: 21,3727 51505 SPSRCS INDEX AXISCTR # JET SENSE TEST
064363,000151: 21,3730 11525 CCS TJU
064364,000152: 21,3731 13713 TCF PLUSFIRE # JETS FIRING POSITIVELY
064365,000153: 21,3732 13734 TCF +2
064366,000154: 21,3733 13707 TCF NEGFIRE # JETS FIRING NEGATIVELY
064367,000155: 21,3734 55745 TS OLDSENSE # JETS OFF
064368,000156: 21,3735 31427 SPSSTART CA EDOT # OUTER RATE LIMIT TEST
064369,000157: 21,3736 00006 EXTEND
064370,000158: 21,3737 74766 MP RATELIM1
064371,000159: 21,3740 10000 CCS A
064372,000160: 21,3741 13760 TCF NEGTHRST # OUTER RATE LIMIT EXCEEDED
064373,000161: 21,3742 13744 TCF +2
064374,000162: 21,3743 13647 TCF POSTHRST # OUTER RATE LIMIT EXCEEDED
064375,000163: 21,3744 31427 CA EDOT # COAST ZONE TEST
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Page 1510
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064377,000165: 21,3745 61752 AD E
064378,000166: 21,3746 00006 EXTEND
064379,000167: 21,3747 71411 MP DKDB # PAD LOADED DEADBAND. FRESHSTART: 1.4 DEG
064380,000168: 21,3750 00006 EXTEND
064381,000169: 21,3751 13766 BZF TJZERO
064382,000170:
064383,000171: 21,3752 00006 EXTEND
064384,000172: 21,3753 63762 BZMF +7
064385,000173: 21,3754 31427 CA EDOT
064386,000174: 21,3755 63646 AD RATELIM2
064387,000175: 21,3756 00006 EXTEND
064388,000176: 21,3757 63766 BZMF TJZERO
064389,000177: 21,3760 44736 NEGTHRST CS HALF
064390,000178: 21,3761 13650 TCF POSTHRST +1
064391,000179: 21,3762 43646 +7 CS RATELIM2
064392,000180: 21,3763 61427 AD EDOT
064393,000181: 21,3764 00006 EXTEND
064394,000182: 21,3765 63647 BZMF POSTHRST
064395,000183: 21,3766 34755 TJZERO CA ZERO
064396,000184: 21,3767 13650 TCF POSTHRST +1
064397,000185:
064398,000186: 21,3770 4766 RATELIM1 = CALLCODE # = 00032, CORRESPONDING TO 1.73 DEG/SEC
064399,000187: 21,3770 4767 RATEDB1 = TBUILDFX # = 00045, CORRESPONDS TO 0.101 DEG/SEC
064400,000188:
End of include-file SPS_BACK-UP_RCS_CONTROL.agc. Parent file is MAIN.agc