Source Code

These source-code files were obtained by digitally photographing an Artemis 72 program listing from a private collection and then modifying pre-existing Comanche 55 (Apollo 11) source files to incorporate changes. Note that the page images presented online are of reduced quality, and that additional images may be available. Report any conversion errors or legibility problems in page images to info@sandroid.org. Notations on the program listing read, in part:

	GAP: ASSEMBLE REVISION 072 OF AGC PROGRAM ARTEMIS 
	BY NASA 2021114-011 11:40 FEB. 26, 1971

	THIS AGC PROGRAM SHALL ALSO BE REFERRED TO AS
				COLOSSUS 3
	THIS PROGRAM IS INTENDED FOR USE IN THE CM AS SPECIFIED
	IN REPORT R-577.  THIS PROGRAM WAS PREPARED UNDER OSR
	PROJECT 55-23890, SPONSORED BY THE MANNED SPACECRAFT
	CENTER OF THE NATIONAL AERONAUTICS AND SPACE
	ADMINISTRATION THROUGH CONTRACT NAS 9-4065 WITH THE
	CHARLES STARK DRAPER LABORATORY, MASSACHUSETTS INSTITUTE OF
	TECHNOLOGY, CAMBRIDGE, MASS.

018397,000002:                                                                                                 #  Copyright:     Public domain.
018398,000003:                                                                                                 #  Filename:      GIMBAL_LOCK_AVOIDANCE.agc
018399,000004:                                                                                                 #  Purpose:       Part of the source code for Artemis (i.e., Colossus 3),
018400,000005:                                                                                                 #                 build 072.  This is for the Command Module's (CM) 
018401,000006:                                                                                                 #                 Apollo Guidance Computer (AGC), we believe for 
018402,000007:                                                                                                 #                 Apollo 15-17.
018403,000008:                                                                                                 #  Assembler:     yaYUL
018404,000009:                                                                                                 #  Contact:       Sergio Navarro <sergionavarrog@gmail.com>
018405,000010:                                                                                                 #  Website:       www.ibiblio.org/apollo/index.html
018406,000011:                                                                                                 #  Page scans:    www.ibiblio.org/apollo/ScansForConversion/Artemis072/
018407,000012:                                                                                                 #  Mod history:   2009-08-19 SN   Adapted from corresponding Comanche 055 file.
018408,000013:                                                                                                 #                 2009-09-04 JL   Minor changes.
018409,000014:                                                                                                 #                 2010-02-20 RSB  Un-##'d this header.
018410,000015: 
018411,000016:                                                                                                 # # Page 416
018412,000017: 
018413,000018: 22,2000                                          SETLOC   KALCMON1                              
018414,000019: 22,2000                                          BANK                                           
018415,000020: 
018416,000021: 22,2745                                          COUNT*   $$/KALC                               
018417,000022: 22,2745  E6,1661                                 EBANK=   BCDU                                  
018418,000023: 
018419,000024:                                                                                                 #  DETECTING GIMBAL LOCK
018420,000025: 22,2745  22,2745               LOCSKIRT          EQUALS   WCALC                                 
018421,000026: 22,2745           70740        WCALC             LXC,1    DLOAD*                                
018422,000027: 22,2746           00774                                   RATEINDX                              
018423,000028: 22,2747           05002                                   ARATE,1                               
018424,000029: 22,2750           45002                          SR4      CALL                                  #  COMPUTE THE INCREMENTAL ROTATION MATRIX
018425,000030: 22,2751           44522                                   DELCOMP                               #  DEL CORRESPONDING TO A 1 SEC ROTATION
018426,000031:                                                                                                 #  ABOUT COF
018427,000032: 22,2752           74343                          DLOAD*   VXSC                                  
018428,000033: 22,2753           05002                                   ARATE,1                               
018429,000034: 22,2754           03343                                   COF                                   
018430,000035: 22,2755           77721                          MXV                                            
018431,000036: 22,2756           05014                                   QUADROT                               
018432,000037: 22,2757           17311                          STODL    BRATE                                 
018433,000038: 22,2760           03365                                   AM                                    
018434,000039: 22,2761           55605                          DMP      DDV*                                  
018435,000040: 22,2762           05012                                   ANGLTIME                              
018436,000041: 22,2763           05002                                   ARATE,1                               
018437,000042: 22,2764           77661                          SR                                             
018438,000043: 22,2765           20606                                   5                                     
018439,000044: 22,2766           03317                          STORE    TM                                    
018440,000045: 22,2767           77214                          BON      VLOAD                                 
018441,000046: 22,2770           00313                                   CYC61FLG                              
018442,000047: 22,2771           71747                                   RCYCLR61                              
018443,000048: 22,2772           03311                                   BRATE                                 
018444,000049: 22,2773           77761                          VXSC                                           
018445,000050: 22,2774           05036                                   BIASCALE                              
018446,000051: 22,2775           03275                          STORE    BIASTEMP                              #  ATTITUDE ERROR BIAS TO PREVENT OVERSHOOT
018447,000052:                                                                                                 #  IN SYSTEM
018448,000053: 22,2776           77614                          SETGO                                          #  STATE SWITCH CALCMAN2 (43D)
018449,000054: 22,2777           01035                                   CALCMAN2                              #  0(OFF) = BYPASS STARTING PROCEDURE
018450,000055: 22,3000           45053                                   NEWANGL    +1                         #  1(ON) = START MANEUVER
018451,000056: 
018452,000057: 
018453,000058: 22,3001           00044 15053  ARATE             2DEC     .0022222222                            #  = .05 DEG/SEC
018454,000059: 22,3003           00221 24255                    2DEC     .0088888889                            #  = .2 DEG/SEC
018455,000060: 22,3005           00554 02660                    2DEC     .0222222222                            #  = .5 DEG/SEC
018456,000061: 22,3007           02660 13301                    2DEC     .0888888889                            #  = 2 DEG/SEC                $22.5 DEG/SEC
018457,000062: 22,3011           00003 04000  ANGLTIME          2DEC     .000190735                            #  = 100B - 19
018458,000063:                                                                                                 #  MANEUVER ANGLE TO MANEUVER TIME
018459,000064:                                                                                                 # # Page 417
018460,000065: 22,3013           03146 14632  QUADROT           2DEC     .1                                    #  ROTATION MATRIX FROM S/C AXES TO CONTROL
018461,000066: 22,3015           00000 00000                    2DEC     0          B-28                       #  AXES (X ROT = -7.25 DEG)
018462,000067: 22,3017           00000 00000                    2DEC     0          B-28                       
018463,000068: 22,3021           00000 00000                    2DEC     0          B-28                       
018464,000069: 22,3023           03131 11275                    2DEC     .099200                               #  =(.1)COS7.25
018465,000070: 22,3025           77461 47370                    2DEC     -.012620                              #  =-(.1)SIN7.25
018466,000071: 22,3027           00000 00000                    2DEC     0          B-28                       
018467,000072: 22,3031           00316 30407                    2DEC     .012620                               #  (.1)SIN7.25
018468,000073: 22,3033           03131 11275                    2DEC     .099200                               #  (.1)COS7.25
018469,000074: 22,3035           00004 05253  BIASCALE          2DEC     .0002543132                            #  = (450/180)(1/0.6)(1/16384)

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