Source Code

This is a reconstruction of the AGC program Luminary 99 Rev 0. It was the second release of the Lunar Module flight software targeted for use in Apollo 11, after Luminary 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.

013659,000002:                                                                                                  ## Copyright:   Public domain.
013660,000003:                                                                                                  ## Filename:    LEM_GEOMETRY.agc
013661,000004:                                                                                                  ## Purpose:     Part of the reconstructed source code for LMY99 Rev 0,
013662,000005:                                                                                                  ##              otherwise known as Luminary Rev 99, the second release
013663,000006:                                                                                                  ##              of the Apollo Guidance Computer (AGC) software for Apollo 11.
013664,000007:                                                                                                  ##              It differs from LMY99 Rev 1 (the flown version) only in the
013665,000008:                                                                                                  ##              placement of a single label. The corrections shown here have
013666,000009:                                                                                                  ##              been verified to have the same bank checksums as AGC developer
013667,000010:                                                                                                  ##              Allan Klumpp's copy of Luminary Rev 99, and so are believed
013668,000011:                                                                                                  ##              to be accurate. This file is intended to be a faithful 
013669,000012:                                                                                                  ##              recreation, except that the code format has been changed to 
013670,000013:                                                                                                  ##              conform to the requirements of the yaYUL assembler rather than 
013671,000014:                                                                                                  ##              the original YUL assembler.
013672,000015:                                                                                                  ##
013673,000016:                                                                                                  ## Assembler:   yaYUL
013674,000017:                                                                                                  ## Contact:     Ron Burkey <info@sandroid.org>.
013675,000018:                                                                                                  ## Website:     www.ibiblio.org/apollo.
013676,000019:                                                                                                  ## Pages:       320-325
013677,000020:                                                                                                  ## Mod history: 2009-05-16 RSB  Adapted from the corresponding 
013678,000021:                                                                                                  ##                              Luminary131 file, using page 
013679,000022:                                                                                                  ##                              images from Luminary 1A.
013680,000023:                                                                                                  ##              2016-12-13 RSB  Proofed text comments with octopus/ProoferComments
013681,000024:                                                                                                  ##                              and corrected the errors found.
013682,000025:                                                                                                  ##              2017-03-07 RSB  Fixed comment-text error noticed while proofing
013683,000026:                                                                                                  ##                              Luminary 116.
013684,000027:                                                                                                  ##              2017-08-01 MAS  Created from LMY99 Rev 1.
013685,000028: 
013686,000029:                                                                                                  ## This source code has been transcribed or otherwise adapted from
013687,000030:                                                                                                  ## digitized images of a hardcopy from the MIT Museum.  The digitization
013688,000031:                                                                                                  ## was performed by Paul Fjeld, and arranged for by Deborah Douglas of
013689,000032:                                                                                                  ## the Museum.  Many thanks to both.  The images (with suitable reduction
013690,000033:                                                                                                  ## in storage size and consequent reduction in image quality as well) are
013691,000034:                                                                                                  ## available online at www.ibiblio.org/apollo.  If for some reason you
013692,000035:                                                                                                  ## find that the images are illegible, contact me at info@sandroid.org
013693,000036:                                                                                                  ## about getting access to the (much) higher-quality images which Paul
013694,000037:                                                                                                  ## actually created.
013695,000038:                                                                                                  ##
013696,000039:                                                                                                  ## The code has been modified to match LMY99 Revision 0, otherwise
013697,000040:                                                                                                  ## known as Luminary Revision 99, the Apollo 11 software release preceeding
013698,000041:                                                                                                  ## the listing from which it was transcribed. It has been verified to
013699,000042:                                                                                                  ## contain the same bank checksums as AGC developer Allan Klumpp's listing
013700,000043:                                                                                                  ## of Luminary Revision 99 (for which we do not have scans).
013701,000044:                                                                                                  ##
013702,000045:                                                                                                  ## Notations on Allan Klumpp's listing read, in part:
013703,000046:                                                                                                  ##
013704,000047:                                                                                                  ##      ASSEMBLE REVISION 099 OF AGC PROGRAM LUMINARY BY NASA 2021112-51
013705,000048: 

Page 320

013707,000050: 23,2041                                           BANK     23                                    
013708,000051: 13,2000                                           SETLOC   LEMGEOM                               
013709,000052: 13,2000                                           BANK                                           
013710,000053: 
013711,000054: 13,2070  30,2000                                  SBANK=   LOWSUPER                              
013712,000055: 13,2070  E5,1642                                  EBANK=   XSM                                   
013713,000056: 
013714,000057:                                                                                                  #  THESE TWO ROUTINES COMPUTE THE ACTUAL STATE VECTOR FOR LM,CSM BY ADDING
013715,000058:                                                                                                  #  THE CONIC R,V AND THE DEVIATIONS R,V.  THE STATE VECTORS ARE CONVERTED TO
013716,000059:                                                                                                  #  METERS B-29 AND METERS/CSEC B-7 AND STORED APPROPRIATELY IN RN,VN OR
013717,000060:                                                                                                  #  R-OTHER,V-OTHER FOR DOWNLINK.  THE ROUTINES NAMES ARE SWITCHED IN THE
013718,000061:                                                                                                  #  OTHER VEHICLES COMPUTER.
013719,000062: 
013720,000063:                                                                                                  #  INPUT
013721,000064:                                                                                                  #        STATE VECTOR IN TEMPORARY STORAGE AREA
013722,000065:                                                                                                  #        IF STATE VECTOR IS SCALED POS B27 AND VEL B5
013723,000066:                                                                                                  #                SET X2 TO +2
013724,000067:                                                                                                  #        IF STATE VECTOR IS SCALED POS B29 AND VEL B7
013725,000068:                                                                                                  #                SET X2 TO 0
013726,000069: 
013727,000070:                                                                                                  #  OUTPUT
013728,000071:                                                                                                  #        R(T) IN RN, V(T) IN VN, T IN PIPTIME
013729,000072:                                                                                                  #  OR
013730,000073:                                                                                                  #        R(T) IN R-OTHER, V(T) IN V-OTHER        (T IS DEFINED BY T-OTHER)
013731,000074: 
013732,000075: 13,2070                                           COUNT*   $$/GEOM                               
013733,000076: 13,2070           43414        SVDWN2             BOF      RVQ                                   #  SW=1=AVETOMID DOING W-MATRIX INTEG.
013734,000077: 13,2071           04756                                    AVEMIDSW                              
013735,000078: 13,2072           26073                                    +1                                    
013736,000079: 13,2073           53775                           VLOAD    VSL*                                  
013737,000080: 13,2074           01521                                    TDELTAV                               
013738,000081: 13,2075           57605                                    0          -7,2                       
013739,000082: 13,2076           53655                           VAD      VSL*                                  
013740,000083: 13,2077           01535                                    RCV                                   
013741,000084: 13,2100           57576                                    0,2                                   
013742,000085: 13,2101           25221                           STOVL    RN                                    
013743,000086: 13,2102           01527                                    TNUV                                  
013744,000087: 13,2103           53257                           VSL*     VAD                                   
013745,000088: 13,2104           57602                                    0          -4,2                       
013746,000089: 13,2105           01543                                    VCV                                   
013747,000090: 13,2106           77657                           VSL*                                           
013748,000091: 13,2107           57576                                    0,2                                   
013749,000092: 13,2110           15227                           STODL    VN                                    
013750,000093: 13,2111           01517                                    TET                                   
013751,000094: 13,2112           01235                           STORE    PIPTIME                               
013752,000095: 13,2113           77616                           RVQ                                            

Page 321

013754,000097: 13,2114           53775        SVDWN1             VLOAD    VSL*                                  
013755,000098: 13,2115           01521                                    TDELTAV                               
013756,000099: 13,2116           57605                                    0          -7,2                       
013757,000100: 13,2117           53655                           VAD      VSL*                                  
013758,000101: 13,2120           01535                                    RCV                                   
013759,000102: 13,2121           57576                                    0,2                                   
013760,000103: 13,2122           25720                           STOVL    R-OTHER                               
013761,000104: 13,2123           01527                                    TNUV                                  
013762,000105: 13,2124           53257                           VSL*     VAD                                   
013763,000106: 13,2125           57602                                    0          -4,2                       
013764,000107: 13,2126           01543                                    VCV                                   
013765,000108: 13,2127           77657                           VSL*                                           
013766,000109: 13,2130           57576                                    0,2                                   
013767,000110: 13,2131           01726                           STORE    V-OTHER                               
013768,000111: 13,2132           77616                           RVQ                                            
013769,000112: 

Page 322

013771,000114:                                                                                                  #  THE FOLLOWING ROUTINE TAKES A HALF UNIT TARGET VECTOR REFERRED TO NAV BASE COORDINATES AND FINDS BOTH
013772,000115:                                                                                                  #  GIMBAL ORIENTATIONS AT WHICH THE RR MIGHT SIGHT THE TARGET.  THE GIMBAL ANGLES CORRESPONDING TO THE PRESENT MODE
013773,000116:                                                                                                  #  ARE LEFT IN MODEA AND THOSE WHICH WOULD BE USED AFTER A REMODE IN MODEB.  THIS ROUTINE ASSUMES MODE 1 IS TRUNNION
013774,000117:                                                                                                  #  ANGLE LESS THAN 90 DEGS IN ABS VALUE WITH ARBITRARY SHAFT, WITH A CORRESPONDING DEFINITION FOR MODE 2.  MODE
013775,000118:                                                                                                  #  SELECTION AND LIMIT CHECKING ARE DONE ELSEWHERE.
013776,000119: 
013777,000120:                                                                                                  #  THE MODE 1 CONFIGURATION IS CALCULATED FROM THE VECTOR AND THEN MODE 2 IS FOUND USING THE RELATIONS
013778,000121: 
013779,000122:                                                                                                  #        S(2) = 180 + S(1)
013780,000123:                                                                                                  #        T(2) = 180 - T(1)
013781,000124: 
013782,000125:                                                                                                  #  THE VECTOR ARRIVES IN MPAC WHERE TRG*SMNG OR *SMNB* WILL HAVE LEFT IT.
013783,000126: 
013784,000127: 13,2133           00041        RRANGLES           STORE    32D                                   
013785,000128: 13,2134           57545                           DLOAD    DCOMP                                 #  SINCE WE WILL FIND THE MODE 1 SHAFT
013786,000129: 13,2135           00043                                    34D                                   #  ANGLE LATER, WE CAN FIND THE MODE 1
013787,000130: 13,2136           67401                           SETPD    ASIN                                  #  TRUNNION BY SIMPLY TAKING THE ARCSIN OF
013788,000131: 13,2137           00001                                    0                                     #  THE Y COMPONENT, THE ASIN GIVING AN
013789,000132: 13,2140           44206                           PUSH     BDSU                                  #  ANSWER WHOSE ABS VAL IS LESS THAN 90 DEG
013790,000133: 13,2141           24005                                    LODPHALF                              
013791,000134: 13,2142           14005                           STODL    4                                     #  MODE 2 TRUNNION TO 4.
013792,000135: 
013793,000136: 13,2143           24007                                    LO6ZEROS                              
013794,000137: 13,2144           24043                           STOVL    34D                                   #  UNIT THE PROJECTION OF THE VECTOR
013795,000138: 13,2145           00041                                    32D                                   #        IN THE X-Z PLANE
013796,000139: 13,2146           41056                           UNIT     BOVB                                  #  IF OVERFLOW, TARGET VECTOR IS ALONG Y
013797,000140: 13,2147           52421                                    LUNDESCH                              #  CALL FOR MANEUVER UNLESS ON LUNAR SURF
013798,000141: 13,2150           14041                           STODL    32D                                   #  PROJECTION VECTOR.
013799,000142: 13,2151           00041                                    32D                                   
013800,000143: 13,2152           44142                           SR1      STQ                                   
013801,000144: 13,2153           00051                                    S2                                    
013802,000145: 13,2154           14023                           STODL    SINTH                                 #  USE ARCTRIG SINCE SHAFT COULD BE ARB.
013803,000146: 13,2155           00045                                    36D                                   
013804,000147: 13,2156           77742                           SR1                                            
013805,000148: 13,2157           34021                           STCALL   COSTH                                 
013806,000149: 13,2160           47320                                    ARCTRIG                               

Page 323

013808,000151: 13,2161           43206                           PUSH     DAD                                   #  MODE 1 SHAFT TO 2.
013809,000152: 13,2162           24005                                    LODPHALF                              
013810,000153: 13,2163           24007                           STOVL    6                                     
013811,000154: 13,2164           00005                                    4                                     
013812,000155: 13,2165           77634                           RTB                                            #  FIND MODE 2 CDU ANGLES.
013813,000156: 13,2166           21635                                    2V1STO2S                              
013814,000157: 13,2167           25112                           STOVL    MODEB                                 
013815,000158: 13,2170           00001                                    0                                     
013816,000159: 13,2171           77634                           RTB                                            #  MODE 1 ANGLES TO MODE A.
013817,000160: 13,2172           21635                                    2V1STO2S                              
013818,000161: 13,2173           01110                           STORE    MODEA                                 
013819,000162: 13,2174           77776                           EXIT                                           
013820,000163: 
013821,000164: 13,2175           40110                           CS       RADMODES                              #  SWAP MODEA AND MODEB IF RR IN MODE 2.
013822,000165: 13,2176           74740                           MASK     ANTENBIT                              
013823,000166: 13,2177           10000                           CCS      A                                     
013824,000167: 13,2200           12204                           TCF      +4                                    
013825,000168: 
013826,000169: 13,2201           53110                           DXCH     MODEA                                 
013827,000170: 13,2202           53112                           DXCH     MODEB                                 
013828,000171: 13,2203           53110                           DXCH     MODEA                                 
013829,000172: 
013830,000173: 13,2204           06037                           TC       INTPRET                               
013831,000174: 13,2205           77650                           GOTO                                           
013832,000175: 13,2206           00051                                    S2                                    

Page 324

013834,000177:                                                                                                  #  GIVEN RR TRUNNION AND SHAFT (T,S) IN TANGNB,+1, FIND THE ASSOCIATED
013835,000178:                                                                                                  #  LINE OF SIGHT IN NAV BASE AXES.  THE HALF UNIT VECTOR, .5(SIN(S)COS(T),
013836,000179:                                                                                                  #  -SIN(T),COS(S)COS(T)) IS LEFT IN MPAC AND 32D.
013837,000180: 
013838,000181: 23,2000                                           SETLOC   INFLIGHT                              
013839,000182: 23,2000                                           BANK                                           
013840,000183: 
013841,000184: 23,2041                                           COUNT*   $$/GEOM                               
013842,000185: 
013843,000186: 23,2041           47135        RRNB               SLOAD    RTB                                   
013844,000187: 23,2042           03753                                    TANGNB                                
013845,000188: 23,2043           21576                                    CDULOGIC                              
013846,000189: 23,2044           41401                           SETPD    PUSH                                  #  TRUNNION ANGLE TO 0
013847,000190: 23,2045           00001                                    0                                     
013848,000191: 23,2046           57556                           SIN      DCOMP                                 
013849,000192: 23,2047           14043                           STODL    34D                                   #  Y COMPONENT
013850,000193: 
013851,000194: 23,2050           41546                           COS      PUSH                                  #  .5 COS(T) TO 0
013852,000195: 23,2051           47135                           SLOAD    RTB                                   
013853,000196: 23,2052           03754                                    TANGNB     +1                         
013854,000197: 23,2053           21576                                    CDULOGIC                              
013855,000198: 23,2054           71406        RRNB1              PUSH     COS                                   #  SHAFT ANGLE TO 2
013856,000199: 23,2055           72405                           DMP      SL1                                   
013857,000200: 23,2056           00001                                    0                                     
013858,000201: 23,2057           14045                           STODL    36D                                   #  Z COMPONENT
013859,000202: 
013860,000203: 23,2060           41356                           SIN      DMP                                   
013861,000204: 23,2061           77752                           SL1                                            
013862,000205: 23,2062           24041                           STOVL    32D                                   
013863,000206: 23,2063           00041                                    32D                                   
013864,000207: 23,2064           77616                           RVQ                                            
013865,000208: 
013866,000209:                                                                                                  #  THIS ENTRY TO RRNB REQUIRES THE TRUNNION AND SHAFT ANGLES IN MPAC AND MPAC +1 RESPECTIVELY
013867,000210: 
013868,000211: 23,2065           14025        RRNBMPAC           STODL    20D                                   #  SAVE SHAFT CDU IN 21.
013869,000212: 23,2066           00155                                    MPAC                                  #  SET MODE TO DP.  (THE PRECEEDING STORE
013870,000213:                                                                                                  #  MAY BE DP, TP OR VECTOR.)
013871,000214: 23,2067           40234                           RTB      SETPD                                 
013872,000215: 23,2070           21576                                    CDULOGIC                              
013873,000216: 23,2071           00001                                    0                                     
013874,000217: 23,2072           73406                           PUSH     SIN                                   #  TRUNNION ANGLE TO 0
013875,000218: 23,2073           77676                           DCOMP                                          
013876,000219: 23,2074           14043                           STODL    34D                                   #  Y COMPONENT
013877,000220: 23,2075           41546                           COS      PUSH                                  #  .5COS(T) TO 0
013878,000221: 23,2076           47135                           SLOAD    RTB                                   #  PICK UP CDU'S.
013879,000222: 23,2077           00026                                    21D                                   
013880,000223: 23,2100           21576                                    CDULOGIC                              
013881,000224: 23,2101           77650                           GOTO                                           
013882,000225: 23,2102           46054                                    RRNB1                                 

Page 325
This page has nothing on it.

013885,000228: 
013886,000229: 

End of include-file LEM_GEOMETRY.agc.  Parent file is MAIN.agc