Source Code

These source-code files were transcribed from scans made from Don Eyles's personal copy of BURST120 (SUNBURST 120). They were scanned at archive.org's Boston facility, and the scanning was sponsored by Mike Stewart. The code was transcribed from these scans by a team of volunteers who are referenced in the program comments. Comments from the original source code are in ALL-CAPS, whereas comments added later in transcription are in Mixed-Case. In some cases, where similar code blocks exist in previously-transcribed AGC programs (primarily Luminary 99, from Apollo 11) those code blocks were used as a starting point and then corrected to agree with the BURST120 scans. The full scans are available at the Virtual AGC project's collection at archive.org, while more-convenient reduced-size (but reduced-quality) images are available at the main Virtual AGC website. Report any errors noted by creating an issue report at the Virtual AGC project's GitHub repository. Notations on the program listing read, in part:

	YUL SYSTEM FOR AGC: REVISION 0 OF PROGRAM BURST120 
	BY NASA 2021106-031 DEC 7, 1967

	THIS LISTING IS A COPY OF A VERSION OF THE PROGRAM INTENDED 
	FOR USE IN THE ON-BOARD PRIMARY GUIDANCE COMPUTER IN THE 
	UNMANNED FLIGHT OF APOLLO LUNAR MODULE 1 --- THE AS206 MISSION.
Note that the date is the date of the printout, not the date of the program revision.

035946,000002:                                                                                                  ## Copyright:    Public domain.
035947,000003:                                                                                                  ## Filename:     AVERAGE_G_INTEGRATOR.agc
035948,000004:                                                                                                  ## Purpose:      A module for revision 0 of BURST120 (Sunburst). It 
035949,000005:                                                                                                  ##               is part of the source code for the Lunar Module's
035950,000006:                                                                                                  ##               (LM) Apollo Guidance Computer (AGC) for Apollo 5.
035951,000007:                                                                                                  ## Assembler:    yaYUL
035952,000008:                                                                                                  ## Contact:      Ron Burkey <info@sandroid.org>.
035953,000009:                                                                                                  ## Website:      www.ibiblio.org/apollo/index.html
035954,000010:                                                                                                  ## Mod history:  2016-09-30 RSB  Created draft version.
035955,000011:                                                                                                  ##               2016-10-29 MAS  Adapted from Colossus 237.
035956,000012:                                                                                                  ##               2016-10-31 RSB  Typos.
035957,000013:                                                                                                  ##               2016-12-06 RSB  Comment-proofing via octopus/ProoferComments;
035958,000014:                                                                                                  ##                               no changes were made.
035959,000015: 

Page 842

035961,000017:                                                                                                  #  *************************************************************************************************************
035962,000018: 
035963,000019:                                                                                                  #           ROUTINE CALCRVG INTEGRATES THE EQUATIONS OF MOTION BY AVERAGING THE THRUST AND GRAVITATIONAL
035964,000020:                                                                                                  #  ACCELERATIONS OVER A TIME INTERVAL OF 2 SECONDS.
035965,000021: 
035966,000022:                                                                                                  #           FOR THE EARTH-CENTERED GRAVITATIONAL FIELD, THE PERTURBATION DUE TO OBLATENESS IS COMPUTED TO THE FIRST
035967,000023:                                                                                                  #  HARMONIC COEFFICIENT J.
035968,000024: 
035969,000025:                                                                                                  #           ROUTINE CALCRVG REQUIRES...
035970,000026:                                                                                                  #                  1) THRUST ACCELERATION INCREMENTS IN DELV SCALED SAME AS PIPAX,Y,Z
035971,000027:                                                                                                  #                  2) VN SCALED 2(+7)M/CS.
035972,000028:                                                                                                  #                  3) PUSHDOWN COUNTER SET TO ZERO.
035973,000029:                                                                                                  #  IT LEAVES RN1 UPDATED (SCALED AT 2(+24)M, VN1 (SCALED AT 2(+7)M/CS), ANDGDT1/2 (SCALED AT 2(+7)M/CS).
035974,000030: 
035975,000031: 
035976,000032: 30,3103                                           BANK     30                                    
035977,000033: 30,3103  E5,1544                                  EBANK=   EVEX                                  
035978,000034: 
035979,000035: 30,3103           77656        CALCGRAV           UNIT                                           #  ENTER WITH RN AT 2(+24)M IN VAC
035980,000036: 30,3104           01033                           STORE    UNITR                                 
035981,000037: 30,3105           41441                           DOT      PUSH                                  
035982,000038: 30,3106           01041                                    UNITW                                 
035983,000039: 30,3107           56316                           DSQ      DDV                                   
035984,000040: 30,3110           21171                                    DP1/10                                
035985,000041: 30,3111           65221                           BDSU     PDDL                                  
035986,000042: 30,3112           21167                                    DP1/8TH                               
035987,000043: 30,3113           00045                                    36D                                   
035988,000044: 30,3114           15047                           STODL    RMAG                                  
035989,000045: 30,3115           21173                                    J(RE)SQ                               
035990,000046: 30,3116           77671                           DDV                                            
035991,000047: 30,3117           00043                                    34D                                   
035992,000048: 30,3120           00041                           STORE    32D                                   
035993,000049: 30,3121           77605                           DMP                                            
035994,000050: 30,3122           65361                           VXSC     PDDL                                  
035995,000051: 30,3123           01033                                    UNITR                                 
035996,000052: 30,3124           74205                           DMP      VXSC                                  
035997,000053: 30,3125           00041                                    32D                                   
035998,000054: 30,3126           01041                                    UNITW                                 
035999,000055: 30,3127           53255                           VAD      VAD                                   
036000,000056: 30,3130           01033                                    UNITR                                 
036001,000057: 30,3131           56325                           PDDL     DDV                                   
036002,000058: 30,3132           21175                                    -MUDT                                 
036003,000059: 30,3133           00043                                    34D                                   
036004,000060: 30,3134           45561                           VXSC     STADR                                 
036005,000061: 30,3135           76712                           STORE    GDT1/2                                
036006,000062: 
036007,000063: 30,3136           77616                           RVQ                                            
036008,000064: 
036009,000065: 30,3137           74375        CALCRVG            VLOAD    VXSC                                  
036010,000066: 30,3140           00404                                    DELV                                  

Page 843

036012,000068: 30,3141           21165                                    KPIP1                                 
036013,000069: 30,3142           44006                           PUSH     STQ                                   #  DV/2 TO PD SCALED AT 2(+7)M/CS
036014,000070: 30,3143           00037                                    31D                                   
036015,000071: 30,3144           41455                           VAD      PUSH                                  #  (DV-OLDGDT)/2 TO PD SCALED AT 2(+7)M/CS
036016,000072: 30,3145           01025                                    GDT/2                                 
036017,000073: 30,3146           74255                           VAD      VXSC                                  
036018,000074: 30,3147           01017                                    VN                                    
036019,000075: 30,3150           21177                                    2SEC(17)                              
036020,000076: 30,3151           77655                           VAD                                            
036021,000077: 30,3152           01011                                    RN                                    
036022,000078: 30,3153           35051                           STCALL   RN1                                   #  TEMP STORAGE OF RN SCALED 2(+24)M
036023,000079: 30,3154           61103                                    CALCGRAV                              
036024,000080: 

Both VADs on the following line are circled.

036026,000082: 30,3155           53255                           VAD      VAD                                   
036027,000083: 30,3156           77655                           VAD                                            
036028,000084: 30,3157           01017                                    VN                                    
036029,000085: 30,3160           35057                           STCALL   VN1                                   #  TEMP STORAGE OF VN SCALED 2(+7)M/CS
036030,000086: 30,3161           00037                                    31D                                   
036031,000087: 
036032,000088: 30,3162           03215 27057  KPIP               2DEC     .1024                                 #  SCALES DELV TO 2(+4)
036033,000089: 
036034,000090: 30,3164           00150 33343  KPIP1              2DEC     0.0064                                
036035,000091: 
036036,000092: 30,3166           04000 00000  DP1/8TH            2DEC     0.125                                 
036037,000093: 
036038,000094: 30,3170           03146 14632  DP1/10             2DEC     0.1                                   
036039,000095: 
036040,000096: 30,3172           00036 30103  J(RE)SQ            2DEC     0.060066630 B-5                        #       SCALED AT 2(+45)
036041,000097: 
036042,000098: 30,3174           77774 53772  -MUDT              2DEC*    -7.9720645 E+12       B-55*           
036043,000099: 
036044,000100: 30,3176           00031 00000  2SEC(17)           2DEC     200        B-17                       
036045,000101: 
036046,000102: 30,3200           04000 00000  DP2(-3)            2DEC     0.125                                 
036047,000103: 
036048,000104: 30,3202           00224 17561  MUEARTH            2DEC     0.009063188                            #  3.98603223 E14 SCALED AT 2(42)M(3)/CS(2)
036049,000105: 
036050,000106: 30,3204           00164 34414  MUMOON             2DEC     0.007134481                            #  4.90277800 E12 SCALED AT 2(36)M(3)/CS(2)

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