GAP: ASSEMBLE REVISION 131 OF AGC PROGRAM LUMINARY BY NASA 2021112-091 17:53 DEC. 19, 1969Note that the date is the date the printout was made, not the date on which the program revision was released, although these happen to be very close together.
Source Code
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This source code is very close to the Apollo Guidance Computer software for the
Apollo 13 Lunar module. This revision of the Luminary 131 program is from December
of 1969, whereas there was a later revision in January of 1970, and still another
revision in February, which is the code that flew on the mission.
As far as this transcription is concerned, it was originally from a copy made in 1991 of
a printout from the collection of AGC developer Don Eyles for collector David Craig.
It was subsequently scanned by Gary Neff, reprocessed for online
presentation at the now-discontinued History of Recent Science and Technology (HRST) website
of MIT's Dibner Institute (the full-quality scans being discarded in the process),
and finally transcribed by Ron Burkey for the Virtual AGC Project. Although a
high-quality replacement scan for a completely illegible page was later provided by Gary
Neff, the reduced legibility of the reprocessed HRST posting nevertheless caused many
errors to be introduced into the transcription. Accordingly, a second scan of the same physical
printout was made in 2017 for the Virtual AGC Project's collection at the Internet Archive,
and used to correct the transcription errors. All of the scanned materials mentioned,
as well as other Luminary 131 related material, are available online.
Don Eyles apprently made additional hand-written notes in printout between 1991 and 2017,
so the two scans are not identical in that respect. The page-headings in the printout read, in part:GAP: ASSEMBLE REVISION 131 OF AGC PROGRAM LUMINARY BY NASA 2021112-091 17:53 DEC. 19, 1969Note that the date is the date the printout was made, not the date on which the program revision was released, although these happen to be very close together. |
015261,000002: ## Copyright: Public domain.
015262,000003: ## Filename: KALCMANU_STEERING.agc
015263,000004: ## Purpose: A section of Luminary 1C, revision 131.
015264,000005: ## It is part of the source code for the Lunar Module's (LM)
015265,000006: ## Apollo Guidance Computer (AGC) for Apollo 13.
015266,000007: ## This file is intended to be a faithful transcription, except
015267,000008: ## that the code format has been changed to conform to the
015268,000009: ## requirements of the yaYUL assembler rather than the
015269,000010: ## original YUL assembler.
015270,000011: ## Reference: pp. 367-371
015271,000012: ## Contact: Ron Burkey <info@sandroid.org>.
015272,000013: ## Website: www.ibiblio.org/apollo/index.html
015273,000014: ## Mod history: 05/11/03 RSB Began transcribing.
015274,000015: ## 05/14/05 RSB Corrected website reference above.
015275,000016: ## 2011-05-07 JL Removed workarounds.
015276,000017: ## 2017-01-06 RSB Page numbers now agree with those on the
015277,000018: ## original harcopy, as opposed to the PDF page
015278,000019: ## numbers in 1701.pdf.
015279,000020: ## 2017-01-28 RSB WTIH -> WITH.
015280,000021: ## 2017-02-23 RSB Proofed comment text using octopus/ProoferComments.
015281,000022: ## 2017-02-28 RSB Fixed lingering typos.
015282,000023: ## 2017-03-17 RSB Comment-text fixes identified in diff'ing
015283,000024: ## Luminary 99 vs Comanche 55.
015284,000025:
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Page 367 |
015286,000027: # GENERATION OF STEERING COMMANDS FOR DIGITAL AUTOPILOT FREE FALL MANEUVERS
015287,000028:
015288,000029: # NEW COMMANDS WILL BE GENERATED EVERY ONE SECOND DURING THE MANEUVER
015289,000030:
015290,000031: 22,3003 E6,1706 EBANK= TTEMP
015291,000032:
015292,000033: 22,3003 04616 NEWDELHI TC BANKCALL # CHECK FOR AUTO STABILIZATION
015293,000034: 22,3004 54266 CADR ISITAUTO # ONLY
015294,000035: 22,3005 10000 CCS A
015295,000036: 22,3006 12730 TCF NOGO -2
015296,000037: 22,3007 06042 NEWANGL TC INTPRET
015297,000038: 22,3010 75160 AXC,1 AXC,2
015298,000039: 22,3011 03245 MIS # COMPUTE THE NEW MATRIX FROM S/C TO
015299,000040: 22,3012 02230 KEL # STABLE MEMBER AXES
015300,000041: 22,3013 77624 CALL
015301,000042: 22,3014 44312 MXM3
015302,000043: 22,3015 45575 VLOAD STADR
015303,000044: 22,3016 50515 STOVL MIS +12D # CALCULATE NEW DESIRED CDU ANGLES
015304,000045: 22,3017 77626 STADR
015305,000046: 22,3020 50523 STOVL MIS +6D
015306,000047: 22,3021 77626 STADR
015307,000048: 22,3022 74531 STORE MIS
015308,000049: 22,3023 45160 AXC,1 CALL
015309,000050: 22,3024 03245 MIS
015310,000051: 22,3025 44654 DCMTOCDU # PICK UP THE NEW CDU ANGLES FROM MATRIX
015311,000052: 22,3026 77634 RTB
015312,000053: 22,3027 21621 V1STO2S
015313,000054: 22,3030 03303 STORE NCDU # NEW CDU ANGLES
015314,000055: 22,3031 77414 BONCLR EXIT
015315,000056: 22,3032 01215 CALCMAN2
015316,000057: 22,3033 45122 MANUSTAT # TO START MANEUVER
015317,000058: 22,3034 34752 CAF TWO # +0 OTHERWISE
015318,000059: 22,3035 55261 INCRDCDU TS SPNDX
015319,000060: 22,3036 51261 INDEX SPNDX
015320,000061: 22,3037 31675 CA BCDU # INITIAL CDU ANGLES
015321,000062: 22,3040 00006 EXTEND # OR PREVIOUS DESIRED CDU ANGLES
015322,000063: 22,3041 51261 INDEX SPNDX
015323,000064: 22,3042 21702 MSU NCDU
015324,000065: 22,3043 00006 EXTEND
015325,000066: 22,2000 SETLOC KALCMON1
015326,000067: 22,2000 BANK
015327,000068:
015328,000069: 22,3044 73121 MP DT/TAU
015329,000070: 22,3045 10000 CCS A # CONVERT TO 2S COMPLEMENT
015330,000071: 22,3046 64753 AD ONE
015331,000072: 22,3047 13051 TCF +2
015332,000073: 22,3050 40000 COM
015333,000074: 22,3051 51261 INDEX SPNDX
015334,000075: 22,3052 55637 TS DELDCDU # ANGLE INCREMENTS TO BE ADDED TO
015335,000076: 22,3053 51261 INDEX SPNDX # CDUXD, CDUYD, CDUZD EVERY TENTH SECOND
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Page 368 |
015337,000078: 22,3054 31702 CA NCDU # BY LEM DAP
015338,000079: 22,3055 51261 INDEX SPNDX
015339,000080: 22,3056 57675 XCH BCDU
015340,000081: 22,3057 51261 INDEX SPNDX
015341,000082: 22,3060 55634 TS CDUXD
015342,000083: 22,3061 11261 CCS SPNDX
015343,000084: 22,3062 13035 TCF INCRDCDU # LOOP FOR THREE AXES
015344,000085:
015345,000086: 22,3063 00003 RELINT
015346,000087:
015347,000088: # COMPARE PRESENT TIME WITH TIME TO TERMINATE MANEUVER
015348,000089:
015349,000090: 22,3064 03075 TMANUCHK TC TIMECHK
015350,000091: 22,3065 13170 TCF CONTMANU
015351,000092: 22,3066 34753 CAF ONE
015352,000093: 22,3067 00004 MANUSTAL INHINT # END MAJOR PART OF MANEUVER WITHIN 1 SEC
015353,000094: 22,3070 05203 TC WAITLIST # UNDER WAITLIST CALL TO MANUSTOP
015354,000095: 22,3071 E6,1706 EBANK= TTEMP
015355,000096: 22,3071 03213 44066 2CADR MANUSTOP
015356,000097:
015357,000098: 22,3073 00003 RELINT
015358,000099: 22,3074 15155 TCF ENDOFJOB
015359,000100:
015360,000101: 22,3075 00006 TIMECHK EXTEND
015361,000102: 22,3076 40025 DCS TIME2
015362,000103: 22,3077 53707 DXCH TTEMP
015363,000104: 22,3100 00006 EXTEND
015364,000105: 22,3101 31733 DCA TM
015365,000106: 22,3102 21707 DAS TTEMP
015366,000107: 22,3103 11706 CCS TTEMP
015367,000108: 22,3104 00002 TC Q
015368,000109: 22,3105 13107 TCF +2
015369,000110: 22,3106 13117 TCF 2NDRETRN
015370,000111: 22,3107 11707 CCS TTEMP +1
015371,000112: 22,3110 00002 TC Q
015372,000113: 22,3111 13113 TCF MANUOFF
015373,000114: 22,3112 40000 COM
015374,000115: 22,3113 63166 MANUOFF AD ONESEK +1
015375,000116: 22,3114 00006 EXTEND
015376,000117: 22,3115 63117 BZMF 2NDRETRN
015377,000118: 22,3116 24002 INCR Q
015378,000119: 22,3117 24002 2NDRETRN INCR Q
015379,000120: 22,3120 00002 TC Q
015380,000121:
015381,000122: 22,3121 03146 DT/TAU DEC .1
015382,000123:
015383,000124: 22,3122 77776 MANUSTAT EXIT # INITIALIZATION ROUTINE
015384,000125: 22,3123 00006 EXTEND # FOR AUTOMATIC MANEUVERS
015385,000126: 22,3124 30025 DCA TIME2
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Page 369 |
015387,000128: 22,3125 21733 DAS TM # TM+T0 MANEUVER COMPLETION TIME
015388,000129: 22,3126 00006 EXTEND
015389,000130: 22,3127 43166 DCS ONESEK
015390,000131: 22,3130 21733 DAS TM # (TM+T0)-1
015391,000132: 22,3131 00004 INHINT
015392,000133: 22,3132 34752 CAF TWO
015393,000134: 22,3133 55700 RATEBIAS TS KSPNDX
015394,000135: 22,3134 60000 DOUBLE
015395,000136: 22,3135 55701 TS KDPNDX
015396,000137: 22,3136 50000 INDEX A
015397,000138: 22,3137 31724 CA BRATE
015398,000139: 22,3140 51700 INDEX KSPNDX # STORE MANEUVER RATE IN
015399,000140: 22,3141 55642 TS OMEGAPD # OMEGAPD, OMEGAQD, OMEGARD
015400,000141: 22,3142 00006 EXTEND
015401,000142: 22,3143 63145 BZMF +2 # COMPUTE ATTITUDE ERROR
015402,000143: 22,3144 40000 COM # OFFSET = (WX)ABS(WX)/2AJX
015403,000144: 22,3145 00006 EXTEND # WHERE AJX= 2-JET ACCELERATION
015404,000145: 22,3146 73167 MP BIASCALE # = -1/16
015405,000146: 22,3147 00006 EXTEND
015406,000147: 22,3150 51701 INDEX KDPNDX
015407,000148: 22,3151 71724 MP BRATE
015408,000149: 22,3152 00006 EXTEND
015409,000150: 22,3153 51700 INDEX KSPNDX
015410,000151: 22,3154 11530 DV 1JACC # = AJX $ 90 DEG/SEC-SEC
015411,000152: 22,3155 51700 INDEX KSPNDX
015412,000153: 22,3156 55274 TS DELPEROR # $ 180 DEG
015413,000154: 22,3157 11700 CCS KSPNDX
015414,000155: 22,3160 13133 TCF RATEBIAS
015415,000156:
015416,000157: 22,3161 30025 CA TIME1
015417,000158: 22,3162 63166 AD ONESEK +1
015418,000159: 22,3163 57705 XCH NEXTIME
015419,000160: 22,3164 13034 TCF INCRDCDU -1
015420,000161:
015421,000162: 22,3165 00000 ONESEK DEC 0 B-14
015422,000163: 22,3166 00144 DEC 100 B-14
015423,000164:
015424,000165: 22,3167 75777 BIASCALE OCT 75777 # = -1/16
015425,000166:
015426,000167: 22,3170 40025 CONTMANU CS TIME1 # RESET FOR NEXT DCDU UPDATE
015427,000168: 22,3171 61705 AD NEXTIME
015428,000169: 22,3172 10000 CCS A
015429,000170: 22,3173 64753 AD ONE
015430,000171: 22,3174 13177 TCF MANUCALL
015431,000172: 22,3175 64735 AD NEGMAX
015432,000173: 22,3176 40000 COM
015433,000174: 22,3177 00004 MANUCALL INHINT # CALL FOR NEXT UPDATE VIA WAITLIST
015434,000175: 22,3200 05203 TC WAITLIST
015435,000176: 22,3201 E6,1706 EBANK= TTEMP
015436,000177: 22,3201 03206 44066 2CADR UPDTCALL
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Page 370 |
015438,000179: 22,3203 33166 CAF ONESEK +1 # INCREMENT TIME FOR NEXT UPDATE
015439,000180: 22,3204 27705 ADS NEXTIME
015440,000181: 22,3205 15155 TCF ENDOFJOB
015441,000182:
015442,000183: 22,3206 37717 UPDTCALL CAF PRIO26 # SATELLITE PROGRAM TO CALL FOR UPDATE
015443,000184: 22,3207 05105 TC FINDVAC # OF STEERING COMMANDS
015444,000185: 22,3210 E6,1706 EBANK= TTEMP
015445,000186: 22,3210 03003 44066 2CADR NEWDELHI
015446,000187:
015447,000188: 22,3212 05261 TC TASKOVER
015448,000189:
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Page 371 |
015450,000191: # ROUTINE FOR TERMINATING AUTOMATIC MANEUVERS
015451,000192:
015452,000193: 22,3213 34755 MANUSTOP CAF ZERO # ZERO MANEUVER RATES
015453,000194: 22,3214 55641 TS DELDCDU2
015454,000195: 22,3215 55644 TS OMEGARD
015455,000196: 22,3216 55276 TS DELREROR
015456,000197: 22,3217 55640 TS DELDCDU1
015457,000198: 22,3220 55643 TS OMEGAQD
015458,000199: 22,3221 55275 TS DELQEROR
015459,000200: 22,3222 30323 CA CPSI # SET DESIRED GIMBAL ANGLES TO
015460,000201: 22,3223 55636 TS CDUZD # DESIRED FINAL GIMBAL ANGLES
015461,000202: 22,3224 30322 CA CTHETA
015462,000203: 22,3225 55635 TS CDUYD
015463,000204: 22,3226 30321 ENDROLL CA CPHI # NO FINAL YAW
015464,000205: 22,3227 55634 TS CDUXD
015465,000206: 22,3230 34755 CAF ZERO
015466,000207: 22,3231 55642 TS OMEGAPD # I.E. MANEUVER DID NOT GO THRU
015467,000208: 22,3232 55637 TS DELDCDU # GIMBAL LOCK ORIGINALLY
015468,000209: 22,3233 55274 TS DELPEROR
015469,000210: 22,3234 31306 GOODMANU CA ATTPRIO # RESTORE USERS PRIO
015470,000211: 22,3235 54063 TS NEWPRIO
015471,000212:
015472,000213: 22,3236 34755 CA ZERO # ZERO ATTCADR
015473,000214: 22,3237 53305 DXCH ATTCADR
015474,000215:
015475,000216: 22,3240 05116 TC SPVAC # RETURN TO USER
015476,000217:
015477,000218: 22,3241 05261 TC TASKOVER
015478,000219:
015479,000220:
End of include-file KALCMANU_STEERING.agc. Parent file is MAIN.agc