Source Code

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, 1969
Note 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.

020175,000002:                                                                                                  ## Copyright:   Public domain.
020176,000003:                                                                                                  ## Filename:    R60_62.agc
020177,000004:                                                                                                  ## Purpose:     A section of Luminary 1C, revision 131.
020178,000005:                                                                                                  ##              It is part of the source code for the Lunar Module's (LM)
020179,000006:                                                                                                  ##              Apollo Guidance Computer (AGC) for Apollo 13.
020180,000007:                                                                                                  ##              This file is intended to be a faithful transcription, except
020181,000008:                                                                                                  ##              that the code format has been changed to conform to the
020182,000009:                                                                                                  ##              requirements of the yaYUL assembler rather than the 
020183,000010:                                                                                                  ##              original YUL assembler.
020184,000011:                                                                                                  ## Reference:   pp. 476-489
020185,000012:                                                                                                  ## Contact:     Ron Burkey <info@sandroid.org>.
020186,000013:                                                                                                  ## Website:     www.ibiblio.org/apollo/index.html
020187,000014:                                                                                                  ## Mod history: 05/14/03 RSB.   Began transcribing.
020188,000015:                                                                                                  ##              05/14/05 RSB    Corrected website reference above.
020189,000016:                                                                                                  ##              2017-01-06 RSB  Page numbers now agree with those on the
020190,000017:                                                                                                  ##                              original harcopy, as opposed to the PDF page
020191,000018:                                                                                                  ##                              numbers in 1701.pdf.
020192,000019:                                                                                                  ##              2017-01-27 RSB  Back-ported a comment-text fix identified in Luminary 69.
020193,000020:                                                                                                  ##              2017-02-23 RSB  Proofed comment text using octopus/ProoferComments.
020194,000021:                                                                                                  ##              2017-02-28 RSB  Fixed lingering typos.
020195,000022:                                                                                                  ##              2017-03-09 RSB  Comment text fixes noted in proofing Luminary 116.
020196,000023: 

Page 476

020198,000025:                                                                                                  #  MOD NO: 0                             DATE: 1 MAY 1968
020199,000026:                                                                                                  #  MOD BY: DIGITAL DEVEL GROUP           LOG SECTION R60,R62
020200,000027: 
020201,000028:                                                                                                  #  FUNCTIONAL DESCRIPTION:
020202,000029: 
020203,000030:                                                                                                  #  CALLED AS A GENERAL SUBROUTINE TO MANEUVER THE LM TO A SPECIFIED
020204,000031:                                                                                                  #  ATTITUDE.
020205,000032: 
020206,000033:                                                                                                  #  1. IF THE 3-AXIS FLAG IS NOT SET THE FINAL CDU ANGLES ARE
020207,000034:                                                                                                  #  CALCULATED (VECPOINT).
020208,000035: 
020209,000036:                                                                                                  #  2. THE FDAI BALL ANGLES (NOUN 18) ARE CALCULATED (BALLANGS).
020210,000037: 
020211,000038:                                                                                                  #  3. REQUEST FLASHING DISPLAY V50 N18 PLEASE PERFORM AUTO MANEUVER.
020212,000039: 
020213,000040:                                                                                                  #  4. IF PRIORITY DISPLAY FLAG IS SET DO A PHASECHANGE.  THEN AWAIT
020214,000041:                                                                                                  #  ASTRONAUT RESPONSE.
020215,000042: 
020216,000043:                                                                                                  #  5. DISPLAY RESPONSE RETURNS:
020217,000044: 
020218,000045:                                                                                                  #        A.      ENTER - RESET 3-AXIS FLAG AND RETURN TO CLIENT.
020219,000046: 
020220,000047:                                                                                                  #        B.      TERMINATE - IF IN P00 GO TO STEP 5A.  OTHERWISE CHECK IF R61 IS
020221,000048:                                                                                                  #                THE CALLING PROGRAM.  IF IN R61 AN EXIT IS MADE TO GOTOV56.  IF
020222,000049:                                                                                                  #                NOT IN R61 AN EXIT IS DONE VIA GOTOP00H.
020223,000050: 
020224,000051:                                                                                                  #        C.      PROCEED - CONTINUE WITH PROGRAM AT STEP 6.
020225,000052: 
020226,000053:                                                                                                  #  6. IF THE 3-AXIS FLAG IS NOT SET, THE FINAL CDU ANGLES ARE CALCULATED
020227,000054:                                                                                                  #  (VECPOINT).
020228,000055: 
020229,000056:                                                                                                  #  7. THE FDAI BALL ANGLES (NOUN 18) ARE CALCULATED (BALLANGS).
020230,000057: 
020231,000058:                                                                                                  #  8. IF THE G+N SWITCH IS NOT SET GO BACK TO STEP 3.
020232,000059:                                                                                                  #  
020233,000060:                                                                                                  #  9. IF THE AUTO SWITCH IS NOT SET GO BACK TO STEP 3.
020234,000061: 
020235,000062:                                                                                                  #  10. NONFLASHING DISPLAY V06N18 (FDAI ANGLES).
020236,000063: 
020237,000064:                                                                                                  #  11. DO A PHASECHANGE.
020238,000065: 
020239,000066:                                                                                                  #  12. DO A MANEUVER CALCULATION AND ICDU DRIVE ROUTINE TO ACHIEVE FINAL
020240,000067:                                                                                                  #  GIMBAL ANGLES (GOMANUR).
020241,000068: 
020242,000069:                                                                                                  #  13. AT END OF MANEUVER GO TO STEP 3.
020243,000070: 
020244,000071:                                                                                                  #        IF SATISFACTORY MANEUVER STEP 5A EXITS R60.
020245,000072:                                                                                                  #        FOR FURTHER ADJUSTMENT OF THE VEHICLE ATTITUDE ABOUT THE
020246,000073:                                                                                                  #        DESIRED VECTOR, THE ROUTINE MAY BE PERFORMED AGAIN STARTING AT

Page 477

020248,000075:                                                                                                  #        STEP 5C.
020249,000076: 
020250,000077:                                                                                                  #  CALLING SEQUENCE:     TC      BANKCALL
020251,000078:                                                                                                  #                        CADR    R60LEM
020252,000079: 
020253,000080:                                                                                                  #  ERASABLE INITIALIZATION REQUIRED:     SCAXIS, POINTVSM (FOR VECPOINT)
020254,000081:                                                                                                  #                                        3AXISFLG.
020255,000082: 
020256,000083:                                                                                                  #  SUBROUTINES CALLED:   VECPOINT, BALLANGS, GOPERF2R, LINUS, GODSPER,
020257,000084:                                                                                                  #                        GOMANUR, DOWNFLAG, PHASCHNG, UPFLAG
020258,000085: 
020259,000086:                                                                                                  #  NORMAL EXIT MODES:    CAE     TEMPR60         (CALLERS RETURN ADDRESS)
020260,000087:                                                                                                  #                        TC      BANKJUMP
020261,000088: 
020262,000089:                                                                                                  #  ALARMS: NONE
020263,000090: 
020264,000091:                                                                                                  #  OUTPUT: NONE
020265,000092: 
020266,000093:                                                                                                  #  DEBRIS: CPHI, CTHETA, CPSI, 3AXISFLG, TBASE2
020267,000094: 
020268,000095: 34,2000                                           BANK     34                                    
020269,000096: 26,2000                                           SETLOC   MANUVER                               
020270,000097: 26,2000                                           BANK                                           
020271,000098: 
020272,000099: 26,2123     1163                                  EBANK=   TEMPR60                               
020273,000100: 
020274,000101: 26,2123                                           COUNT*   $$/R06                                
020275,000102: 26,2123           04645        R60LEM             TC       MAKECADR                              
020276,000103: 26,2124           55163                           TS       TEMPR60                               
020277,000104: 
020278,000105: 26,2125           34746        REDOMANN           CAF      3AXISBIT                              
020279,000106: 26,2126           70101                           MASK     FLAGWRD5                              #  IS 3-AXIS FLAG SET
020280,000107: 26,2127           10000                           CCS      A                                     
020281,000108: 26,2130           12136                           TCF      TOBALL                                #  YES
020282,000109: 26,2131           06042                           TC       INTPRET                               
020283,000110: 26,2132           77624                           CALL                                           
020284,000111: 26,2133           56040                                    VECPOINT                              #  TO COMPUTE FINAL ANGLES
020285,000112: 26,2134           00322                           STORE    CPHI                                  #  STORE FINAL ANGLES - CPHI, CTHETA, CPSI
020286,000113: 26,2135           77776                           EXIT                                           
020287,000114: 
020288,000115: 26,2136           05504        TOBALL             TC       UPFLAG                                #  INSURE THAT TOTAL ATTITUDE ERRORS ARE
020289,000116: 26,2137           00013                           ADRES    NEEDLFLG                              #  DISPLAYED ON FDAI ERROR NEEDLES
020290,000117: 26,2140           05516                           TC       DOWNFLAG                              
020291,000118: 26,2141           00000                           ADRES    NEED2FLG                              
020292,000119: 26,2142           04616                           TC       BANKCALL                              
020293,000120: 26,2143           54272                           CADR     BALLANGS                              #  TO CONVERT ANGLES TO FDAI
020294,000121: 26,2144           32260        TOBALLA            CAF      V06N18                                
020295,000122: 26,2145           04616                           TC       BANKCALL                              

Page 478

020297,000124: 26,2146           20711                           CADR     GOPERF2R                              #  DISPLAY PLEASE PERFORM AUTO MANEUVER
020298,000125: 26,2147           02246                           TC       R61TEST                               
020299,000126: 26,2150           02154                           TC       REDOMANC                              #  PROCEED
020300,000127: 26,2151           02201                           TC       ENDMANU1                              #  ENTER I.E. FINISHED WITH R60
020301,000128: 26,2152           02205                           TC       CHKLINUS                              #  TO CHECK FOR PRIORITY DISPLAYS
020302,000129: 26,2153           05155                           TC       ENDOFJOB                              
020303,000130: 
020304,000131: 26,2154           34746        REDOMANC           CAF      3AXISBIT                              
020305,000132: 26,2155           70101                           MASK     FLAGWRD5                              #  IS 3-AXIS FLAG SET
020306,000133: 26,2156           10000                           CCS      A                                     
020307,000134: 26,2157           12165                           TCF      TOBALLC                               #  YES
020308,000135: 26,2160           06042                           TC       INTPRET                               
020309,000136: 26,2161           77624                           CALL                                           
020310,000137: 26,2162           56040                                    VECPOINT                              #  TO COMPUTE FINAL ANGLES
020311,000138: 26,2163           00322                           STORE    CPHI                                  #  STORE ANGLES
020312,000139: 26,2164           77776                           EXIT                                           
020313,000140: 
020314,000141: 26,2165           04616        TOBALLC            TC       BANKCALL                              
020315,000142: 26,2166           54272                           CADR     BALLANGS                              #  TO CONVERT ANGLES TO FDAI
020316,000143: 26,2167           02261                           TC       G+N,AUTO                              #  CHECK AUTO MODE
020317,000144: 26,2170           10000                           CCS      A                                     
020318,000145: 26,2171           12144                           TCF      TOBALLA                               #  NOT AUTO, GO REREQUEST AUTO MANEUVER.
020319,000146: 
020320,000147: 26,2172           32260        AUTOMANV           CAF      V06N18                                #  STATIC DISPLAY DURING AUTO MANEUVER
020321,000148: 26,2173           04616                           TC       BANKCALL                              #                                        -
020322,000149: 26,2174           20452                           CADR     GODSPR                                #                                        -
020323,000150: 26,2175           02205                           TC       CHKLINUS                              #  TO CHECK FOR PRIORITY DISPLAYS
020324,000151: 
020325,000152: 26,2176           04616        STARTMNV           TC       BANKCALL                              #  PERFORM MANEUVER VIA KALCMANU
020326,000153: 26,2177           17741                           CADR     GOMANUR                               
020327,000154: 
020328,000155: 26,2200           12144        ENDMANUV           TCF      TOBALLA                               #  FINISHED MANEUVER.
020329,000156: 26,2201           05516        ENDMANU1           TC       DOWNFLAG                              #  RESET 3-AXIS FLAG
020330,000157: 26,2202           00124                           ADRES    3AXISFLG                              
020331,000158: 26,2203           31163                           CAE      TEMPR60                               #                                        -
020332,000159: 26,2204           04640                           TC       BANKJUMP                              #                                        -
020333,000160: 
020334,000161: 26,2205           40100        CHKLINUS           CS       FLAGWRD4                              
020335,000162: 26,2206           74740                           MASK     PDSPFBIT                              #  IS PRIORITY DISPLAY FLAG SET?
020336,000163: 26,2207           10000                           CCS      A                                     #                                        -
020337,000164: 26,2210           00002                           TC       Q                                     #  NO - EXIT
020338,000165: 26,2211           30002                           CA       Q                                     
020339,000166: 26,2212           54156                           TS       MPAC       +2                         #  SAVE RETURN
020340,000167: 26,2213           46250                           CS       THREE                                 #  OBTAIN LOCATION FOR RESTART
020341,000168: 26,2214           60133                           AD       BUF2                                  #  HOLDS Q OF LAST DISPLAY
020342,000169: 26,2215           55054                           TS       TBASE2                                
020343,000170: 
020344,000171: 26,2216           05353                           TC       PHASCHNG                              
020345,000172: 26,2217           00132                           OCT      00132                                 

Page 479

020347,000174: 26,2220           34745                           CAF      BIT7                                  
020348,000175: 26,2221           05464                           TC       LINUS                                 #  GO SET BITS FOR PRIORITY DISPLAY      -
020349,000176: 26,2222           00156                           TC       MPAC       +2                         
020350,000177: 
020351,000178: 26,2223           37717        RELINUS            CAF      PRIO26                                #  RESTORE ORIGINAL PRIORITY
020352,000179: 26,2224           05146                           TC       PRIOCHNG                              
020353,000180: 
020354,000181: 26,2225           34747                           CAF      TRACKBIT                              #  DON'T CONTINUE R60 UNLESS TRACKFLAG ON.
020355,000182: 26,2226           70075                           MASK     FLAGWRD1                              
020356,000183: 26,2227           10000                           CCS      A                                     
020357,000184: 26,2230           12243                           TCF      RER60                                 
020358,000185: 
020359,000186: 26,2231           34745                           CAF      RNDVZBIT                              #  IS IT P20?
020360,000187: 26,2232           70074                           MASK     FLAGWRD0                              
020361,000188: 26,2233           10000                           CCS      A                                     
020362,000189: 26,2234           02240                           TC       +4                                    #  YES
020363,000190: 26,2235           05353                           TC       PHASCHNG                              #  NO, MUST BE P25, SET 2.11 SPOT
020364,000191: 26,2236           40112                           OCT      40112                                 
020365,000192: 
020366,000193: 26,2237           05155                           TC       ENDOFJOB                              
020367,000194: 
020368,000195: 26,2240           05353                           TC       PHASCHNG                              #  SET 2.7 SPOT FOR P20
020369,000196: 26,2241           40072                           OCT      40072                                 
020370,000197: 
020371,000198: 26,2242           05155                           TC       ENDOFJOB                              
020372,000199: 
020373,000200: 26,2243           05504        RER60              TC       UPFLAG                                #  SET PRIO DISPLAY FLAG AFTER RESTART
020374,000201: 26,2244           00077                           ADRES    PDSPFLAG                              
020375,000202: 
020376,000203: 26,2245           01054                           TC       TBASE2                                
020377,000204: 
020378,000205: 26,2246           31010        R61TEST            CA       MODREG                                #  IF WE ARE IN P00 IT MUST BE V49 OR V89
020379,000206: 26,2247           00006                           EXTEND                                         
020380,000207: 26,2250           12201                           BZF      ENDMANU1                              #  THUS WE GO TO ENDEXT VIA USER
020381,000208: 
020382,000209: 26,2251           30100                           CA       FLAGWRD4                              #  ARE WE IN R61 (P20 OR P25)
020383,000210: 26,2252           74740                           MASK     PDSPFBIT                              
020384,000211: 26,2253           00006                           EXTEND                                         
020385,000212: 26,2254           16001                           BZF      GOTOPOOH                              #  NO
020386,000213: 26,2255           06025                           TC       GOTOV56                               #  YES
020387,000214: 
020388,000215: 26,2256           20100        BIT14+7            OCT      20100                                 #                                        -
020389,000216: 26,2257           00203        OCT203             OCT      203                                   
020390,000217: 26,2260           01422        V06N18             VN       0618                                  
020391,000218: 
020392,000219:                                                                                                  #  SUBROUTINE TO CHECK FOR G+N CONTROL, AUTO STABILIZATION
020393,000220: 
020394,000221:                                                                                                  #  RETURNS WITH C(A) = +         IF NOT SET FOR G+N, AUTO
020395,000222:                                                                                                  #  RETURNS WITH C(A) = +0        IF SWITCHES ARE SET
020396,000223: 
020397,000224: 26,2261           00006        G+N,AUTO           EXTEND                                         

Page 480

020399,000226: 26,2262           00030                           READ     CHAN30                                
020400,000227: 26,2263           74742                           MASK     BIT10                                 
020401,000228: 26,2264           10000                           CCS      A                                     
020402,000229: 26,2265           00002                           TC       Q                                     #  NOT IN G+N    C(A) = +
020403,000230: 26,2266           00006        ISITAUTO           EXTEND                                         #  CHECK FOR AUTO MODE
020404,000231: 26,2267           00031                           READ     CHAN31                                
020405,000232: 26,2270           74736                           MASK     BIT14                                 
020406,000233: 26,2271           00002                           TC       Q                                     #  (+) = NOT IN AUTO, (+0) = AOK
020407,000234: 

Page 481

020409,000236:                                                                                                  #  PROGRAM DESCRIPTION BALLANGS
020410,000237:                                                                                                  #  MOD NO.                               LOG SECTION R60,R62
020411,000238:                                                                                                  #  WRITTEN BY RAMA M. AIYAWAR
020412,000239: 
020413,000240:                                                                                                  #  FUNCTIONAL DESCRIPTION
020414,000241: 
020415,000242:                                                                                                  #        COMPUTES LM FDAI BALL DISPLAY ANGLES
020416,000243: 
020417,000244:                                                                                                  #  CALLING SEQUENCE
020418,000245: 
020419,000246:                                                                                                  #        TC      BALLANGS
020420,000247: 
020421,000248:                                                                                                  #  NORMAL EXIT MODE
020422,000249: 
020423,000250:                                                                                                  #        TC      BALLEXIT        (SAVED Q)
020424,000251: 
020425,000252:                                                                                                  #  ALARM OR EXIT MODE    NIL
020426,000253: 
020427,000254:                                                                                                  #  SUBROUTINES CALLED
020428,000255: 
020429,000256:                                                                                                  #        CD*TR*G
020430,000257:                                                                                                  #        ARCTAN
020431,000258: 
020432,000259:                                                                                                  #  INPUT
020433,000260: 
020434,000261:                                                                                                  #        CPHI,CTHETA,CPSI ARE THE ANGLES CORRESPONDING TO AOG, AIG, AMG.  THEY ARE
020435,000262:                                                                                                  #        SP,2S COMPLIMENT SCALED TO HALF REVOLUTION.
020436,000263: 
020437,000264:                                                                                                  #  OUTPUT
020438,000265: 
020439,000266:                                                                                                  #        FDAIX, FDAIY, FDAIZ ARE THE REQUIRED BALL ANGLES SCALED TO HALF REVOLUTION
020440,000267:                                                                                                  #        SP,2S COMPLIMENT.
020441,000268: 
020442,000269:                                                                                                  #        THESE ANGLES WILL BE DISPLAYED AS DEGREES AND HUNDREDTHS, IN THE ORDER ROLL, PITCH, YAW, USING NOUNS 18 & 19.
020443,000270: 
020444,000271:                                                                                                  #  ERASABLE INITIALIZATION REQUIRED
020445,000272: 
020446,000273:                                                                                                  #        CPHI, CTHETA, CPSI      EACH A SP REGISTER
020447,000274: 
020448,000275:                                                                                                  #  DEBRIS
020449,000276: 
020450,000277:                                                                                                  #        A,L,Q,MPAC,SINCDU,COSCDU,PUSHLIST,BALLEXIT
020451,000278: 
020452,000279:                                                                                                  #  NOMENCLATURE: CPHI, CTHETA, & CPSI REPRESENT THE OUTER, INNER, & MIDDLE GIMBAL ANGLES, RESPECTIVELY; OR
020453,000280:                                                                                                  #                EQUIVALENTLY, CDUX, CDUY, & CDUZ.
020454,000281: 
020455,000282:                                                                                                  #  NOTE:  ARCTAN CHECKS FOR OVERFLOW AND SHOULD BE ABLE TO HANDLE ANY SINGULARITIES.
020456,000283: 
020457,000284: 26,2000                                           SETLOC   BAWLANGS                              
020458,000285: 26,2000                                           BANK                                           
020459,000286: 
020460,000287: 26,2272                                           COUNT*   $$/BALL                               
020461,000288: 26,2272           04645        BALLANGS           TC       MAKECADR                              
020462,000289: 26,2273           55337                           TS       BALLEXIT                              
020463,000290: 26,2274           30321                           CA       CPHI                                  

Page 482

020465,000292: 26,2275           54771                           TS       CDUSPOT    +4                         
020466,000293: 26,2276           30322                           CA       CTHETA                                
020467,000294: 26,2277           54765                           TS       CDUSPOT                               
020468,000295: 26,2300           30323                           CA       CPSI                                  
020469,000296: 26,2301           54767                           TS       CDUSPOT    +2                         
020470,000297: 
020471,000298: 26,2302           06042                           TC       INTPRET                               
020472,000299: 26,2303           45001                           SETPD    CALL                                  
020473,000300: 26,2304           00001                                    0D                                    
020474,000301: 26,2305           47545                                    CD*TR*G                               
020475,000302: 
020476,000303: 26,2306           41345                           DLOAD    DMP                                   
020477,000304: 26,2307           00742                                    SINCDUX                               #  SIN (OGA)
020478,000305: 26,2310           00746                                    COSCDUZ                               #  COS (MGA)
020479,000306: 
020480,000307: 26,2311           57552                           SL1      DCOMP                                 #  SCALE
020481,000308: 26,2312           65336                           ARCSIN   PDDL                                  #  YAW = ARCSIN(-SXCZ) INTO 0 PD
020482,000309: 26,2313           00740                                    SINCDUZ                               
020483,000310: 26,2314           14023                           STODL    SINTH                                 #  (SINTH = 18D IN PD)
020484,000311: 26,2315           00746                                    COSCDUZ                               
020485,000312: 26,2316           72405                           DMP      SL1                                   #  RESCALE
020486,000313: 26,2317           00750                                    COSCDUX                               
020487,000314: 26,2320           34021                           STCALL   COSTH                                 #  (COSTH = 16D IN PD)
020488,000315: 26,2321           26506                                    ARCTAN                                
020489,000316: 26,2322           41325                           PDDL     DMP                                   #  ROLL = ARCTAN(SZ/CZCX) INTO 2 PD
020490,000317: 26,2323           00740                                    SINCDUZ                               
020491,000318: 26,2324           00742                                    SINCDUX                               
020492,000319: 26,2325           41512                           SL2      PUSH                                  #  SXSZ INTO 4 PD
020493,000320: 26,2326           65205                           DMP      PDDL                                  #  SXSZCY INTO 4 PD
020494,000321: 26,2327           00744                                    COSCDUY                               
020495,000322: 26,2330           65205                           DMP      PDDL                                  #  SXSZSY INTO 6 PD
020496,000323: 26,2331           00736                                    SINCDUY                               
020497,000324: 26,2332           00750                                    COSCDUX                               
020498,000325: 26,2333           72405                           DMP      SL1                                   #  CXCY
020499,000326: 26,2334           00744                                    COSCDUY                               
020500,000327: 26,2335           45425                           DSU      STADR                                 #  PULL UP FROM 6 PD
020501,000328: 26,2336           63756                           STODL    COSTH                                 #  COSTH = CXCY - SXSZSY
020502,000329: 26,2337           00736                                    SINCDUY                               
020503,000330: 26,2340           72405                           DMP      SL1                                   
020504,000331: 26,2341           00750                                    COSCDUX                               #  CXSY
020505,000332: 26,2342           45415                           DAD      STADR                                 #  PULL UP FROM 4 PD
020506,000333: 26,2343           43754                           STCALL   SINTH                                 #  SINTH = CXSY + SXSZCY
020507,000334: 26,2344           26506                                    ARCTAN                                #  RETURNS WITH D(MPAC) = PITCH
020508,000335: 26,2345           55525                           PDDL     VDEF                                  #  PITCH INTO 2 PD, ROLL INTO MPAC FROM 2PD
020509,000336: 26,2346           77634                           RTB                                            #  VDEF MAKES V(MPAC) = ROLL, PITCH, YAW
020510,000337: 26,2347           21621                                    V1STO2S                               
020511,000338: 26,2350           02345                           STORE    FDAIX                                 #  MODE IS TP
020512,000339: 26,2351           77776                           EXIT                                           
020513,000340: 
020514,000341: 26,2352           31337        ENDBALL            CA       BALLEXIT                              
020515,000342: 

Page 483

020517,000344: 26,2353           04640                           TC       BANKJUMP                              
020518,000345: 

Page 484

020520,000347:                                                                                                  #  PROGRAM DESCRIPTION - VECPOINT
020521,000348: 
020522,000349:                                                                                                  #  THIS INTERPRETIVE SUBROUTINE MAY BE USED TO POINT A SPACECRAFT AXIS IN A DESIRED DIRECTION.  THE AXIS
020523,000350:                                                                                                  #  TO BE POINTED MUST APPEAR AS A HALF UNIT DOUBLE PRECISION VECTOR IN SUCCESSIVE LOCATIONS OF ERASABLE MEMORY
020524,000351:                                                                                                  #  BEGINNING WITH THE LOCATION CALLED SCAXIS.  THE COMPONENTS OF THIS VECTOR ARE GIVEN IN SPACECRAFT COORDINATES.
020525,000352:                                                                                                  #  THE DIRECTION IN WHICH THIS AXIS IS TO BE POINTED MUST APPEAR AS A HALF UNIT DOUBLE PRECISION VECTOR IN
020526,000353:                                                                                                  #  SUCCESSIVE LOCATIONS OF ERASABLE MEMORY BEGINNING WITH THE ADDRESS CALLED POINTVSM.  THE COMPONENTS OF THIS
020527,000354:                                                                                                  #  VECTOR ARE GIVEN IN STABLE MEMBER COORDINATES.  WITH THIS INFORMATION VECPOINT COMPUTES A SET OF THREE GIMBAL
020528,000355:                                                                                                  #  ANGLES (2S COMPLEMENT) CORESPONDING TO THE CROSS-PRODUCT ROTATION BETWEEN SCAXIS AND POINTVSM AND STORES THEM
020529,000356:                                                                                                  #  IN T(MPAC) BEFORE RETURNING TO THE CALLER.
020530,000357: 
020531,000358:                                                                                                  #  THIS ROTATION, HOWEVER, MAY BRING THE S/C INTO GIMBAL LOCK.  WHEN POINTING A VECTOR IN THE Y-Z PLANE,
020532,000359:                                                                                                  #  THE TRANSPONDER AXIS, OR THE AOT FOR THE LEM, THE PROGRAM WILL CORRECT THIS PROBLEM BY ROTATING THE CROSS-
020533,000360:                                                                                                  #  PRODUCT ATTITUDE ABOUT POINTVSM BY A FIXED AMOUNT SUFFICIENT TO ROTATE THE DESIRED S/C ATTITUDE OUT OF GIMBAL
020534,000361:                                                                                                  #  LOCK.  IF THE AXIS TO BE POINTED IS MORE THAN 40.6 DEGREES BUT LESS THAN 60.5 DEG FROM THE +X (OR -X) AXIS,
020535,000362:                                                                                                  #  THE ADDITIONAL ROTATION TO AVOID GIMAL LOCK IS 35 DEGREES.  IF THE AXIS IS MORE THAN 60.5 DEGEES FROM +X (OR -X)
020536,000363:                                                                                                  #  THE ADDITIONAL ROTATION IS 35 DEGREES.  THE GIMBAL ANGLES CORRESPONDING TO THIS ATTITUDE ARE THEN COMPUTED AND
020537,000364:                                                                                                  #  STORED AS 2S COMPLIMENT ANGLES IN T(MPAC) BEFORE RETURNING TO THE CALLER.
020538,000365: 
020539,000366:                                                                                                  #  WHEN POINTING THE X-AXIS, OR THE THRUST VECTOR, OR ANY VECTOR WITHIN 40.6 DEG OF THE X-AXIS, VECPOINT
020540,000367:                                                                                                  #  CANNOT CORRECT FOR A CROSS-PRODUCT ROTATION INTO GIMBAL LOCK.  IN THIS CASE A PLATFORM REALIGNMENT WOULD BE
020541,000368:                                                                                                  #  REQUIRED TO POINT THE VECTOR IN THE DESIRED DIRECTION.  AT PRESENT NO INDICATION IS GIVEN FOR THIS SITUATION
020542,000369:                                                                                                  #  EXCEPT THAT THE FINAL MIDDLE GIMBAL ANGLE IN MPAC +2 IS GREATER THAN 59 DEGREES.
020543,000370: 
020544,000371:                                                                                                  #  CALLING SEQUENCE -
020545,000372: 
020546,000373:                                                                                                  #        1)      LOAD SCAXIS, POINTVSM
020547,000374:                                                                                                  #        2)      CALL
020548,000375:                                                                                                  #                        VECPOINT
020549,000376: 
020550,000377:                                                                                                  #  RETURNS WITH
020551,000378: 
020552,000379:                                                                                                  #        1)      DESIRED OUTER GIMBAL ANGLE IN MPAC
020553,000380:                                                                                                  #        2)      DESIRED INNER GIMBAL ANGLE IN MPAC +1
020554,000381:                                                                                                  #        3)      DESIRED MIDDLE GIMBAL ANGLE IN MPAC +2
020555,000382: 
020556,000383:                                                                                                  #  ERASABLES USED -
020557,000384: 
020558,000385:                                                                                                  #        1)      SCAXIS          6
020559,000386:                                                                                                  #        2)      POINTVSM        6
020560,000387:                                                                                                  #        3)      MIS             18
020561,000388:                                                                                                  #        4)      DEL             18
020562,000389:                                                                                                  #        5)      COF             6
020563,000390:                                                                                                  #        6)      VECQTEMP        1
020564,000391:                                                                                                  #        7)      ALL OF VAC AREA 43
020565,000392: 
020566,000393:                                                                                                  #                        TOTAL   99
020567,000394: 
020568,000395: 27,2000                                           SETLOC   VECPT                                 
020569,000396: 27,2000                                           BANK                                           

Page 485

020571,000398: 27,2032                                           COUNT*   $$/VECPT                              
020572,000399: 
020573,000400: 27,2032  E6,1675                                  EBANK=   BCDU                                  
020574,000401: 
020575,000402: 27,2032           40020        VECPNT1            STQ      BOV                                   #  THIS ENTRY USES DESIRED CDUS
020576,000403: 27,2033           03324                                    VECQTEMP                              #  NOT PRESENT - ENTER WITH CDUD'S IN MPAC
020577,000404: 27,2034           56035                                    VECPNT2                               
020578,000405: 27,2035           52164        VECPNT2            AXC,2    GOTO                                  
020579,000406: 27,2036           03245                                    MIS                                   
020580,000407: 27,2037           56046                                    STORANG                               
020581,000408: 27,2040           40020        VECPOINT           STQ      BOV                                   #  SAVE RETURN ADDRESS
020582,000409: 27,2041           03324                                    VECQTEMP                              
020583,000410: 27,2042           56043                                    VECLEAR                               #  AND CLEAR OVFIND
020584,000411: 27,2043           47164        VECLEAR            AXC,2    RTB                                   
020585,000412: 27,2044           03245                                    MIS                                   #  READ THE PRESENT CDU ANGLES AND
020586,000413: 27,2045           44403                                    READCDUK                              #  STORE THEM IN PD25, 26, 27
020587,000414: 27,2046           34032        STORANG            STCALL   25D                                   
020588,000415: 27,2047           44410                                    CDUTODCM                              #  S/C AXES TO STABLE MEMBER AXES (MIS)
020589,000416: 27,2050           61375                           VLOAD    VXM                                   
020590,000417: 27,2051           03773                                    POINTVSM                              #  RESOLVE THE POINTING DIRECTION VF INTO
020591,000418: 27,2052           03246                                    MIS                                   #  INITIAL S/C AXES (VF = POINTVSM)
020592,000419: 27,2053           77656                           UNIT                                           
020593,000420: 27,2054           00035                           STORE    28D                                   
020594,000421:                                                                                                  #  PD 28 29 30 31 32 33
020595,000422: 27,2055           53435                           VXV      UNIT                                  #  TAKE THE CROSS PRODUCT VF X VI
020596,000423: 27,2056           03765                                    SCAXIS                                #  WHERE VI = SCAXIS
020597,000424: 27,2057           57400                           BOV      VCOMP                                 
020598,000425: 27,2060           56170                                    PICKAXIS                              
020599,000426: 27,2061           17270                           STODL    COF                                   #  CHECK MAGNITUDE
020600,000427: 27,2062           00045                                    36D                                   #  OF CROSS PRODUCT
020601,000428: 27,2063           50025                           DSU      BMN                                   #  VECTOR, IF LESS
020602,000429: 27,2064           14415                                    DPB-14                                #  THAN B-14 ASSUME
020603,000430: 27,2065           56170                                    PICKAXIS                              #  UNIT OPERATION
020604,000431: 27,2066           50375                           VLOAD    DOT                                   #  INVALID.
020605,000432: 27,2067           03765                                    SCAXIS                                
020606,000433: 27,2070           00035                                    28D                                   
020607,000434: 27,2071           65552                           SL1      ARCCOS                                
020608,000435: 27,2072           77624        COMPMATX           CALL                                           #  NOW COMPUTE THE TRANSFORMATION FROM
020609,000436: 27,2073           44527                                    DELCOMP                               #  FINAL S/C AXES TO INITIAL S/C AXES MFI
020610,000437: 27,2074           75160                           AXC,1    AXC,2                                 
020611,000438: 27,2075           03245                                    MIS                                   #  COMPUTE THE TRANSFORMATION FROM FINAL
020612,000439: 27,2076           02230                                    KEL                                   #  S/C AXES TO STABLE MEMBER AXES
020613,000440: 27,2077           77624                           CALL                                           #  MFS = MIS MFI
020614,000441: 27,2100           44312                                    MXM3                                  #  (IN PD LIST)
020615,000442: 
020616,000443: 27,2101           51545                           DLOAD    ABS                                   
020617,000444: 27,2102           00007                                    6                                     #  MFS6 = SIN(CPSI)                      $2
020618,000445: 27,2103           50025                           DSU      BMN                                   
020619,000446: 27,2104           14402                                    SINGIMLC                              #  = SIN(59 DEGS)                        $2
020620,000447: 27,2105           56160                                    FINDGIMB                              #  /CPSI/ LESS THAN 59 DEGS

Page 486

020622,000449:                                                                                                  #  I.E. DESIRED ATTITUDE NOT IN GIMBAL LOCK
020623,000450: 
020624,000451: 27,2106           51545                           DLOAD    ABS                                   #  CHECK TO SEE IF WE ARE POINTING
020625,000452: 27,2107           03765                                    SCAXIS                                #  THE THRUST AXIS
020626,000453: 27,2110           51025                           DSU      BPL                                   
020627,000454: 27,2111           14404                                    SINVEC1                               #  SIN 49.4 DEGS                         $2
020628,000455: 27,2112           56160                                    FINDGIMB                              #  IF SO, WE ARE TRYING TO POINT IT INTO
020629,000456: 27,2113           77775                           VLOAD                                          #  GIMBAL LOCK, ABORT COULD GO HERE
020630,000457: 27,2114           77626                           STADR                                          
020631,000458: 27,2115           50515                           STOVL    MIS        +12D                       
020632,000459: 27,2116           77626                           STADR                                          #  STORE MFS (IN PD LIST) IN MIS
020633,000460: 27,2117           50523                           STOVL    MIS        +6                         
020634,000461: 27,2120           77626                           STADR                                          
020635,000462: 27,2121           50531                           STOVL    MIS                                   
020636,000463: 27,2122           03254                                    MIS        +6                         #  INNER GIMBAL AXIS IN FINAL S/C AXES
020637,000464: 27,2123           57444                           BPL      VCOMP                                 #  LOCATE THE IG AXIS DIRECTION CLOSEST TO
020638,000465: 27,2124           56125                                    IGSAMEX                               #  FINAL X S/C AXIS
020639,000466: 
020640,000467: 27,2125           50035        IGSAMEX            VXV      BMN                                   #  FIND THE SHORTEST WAY OF ROTATING THE 
020641,000468: 27,2126           03765                                    SCAXIS                                #  S/C OUT OF GIMBAL LOCK BY A ROTATION 
020642,000469: 27,2127           56134                                    U=SCAXIS                              #  ABOUT +- SCAXIS, I.E. IF  (IG (SGN MFS3)
020643,000470:                                                                                                  #  X SCAXIS . XF) LESS THAN 0, U = SCAXIS
020644,000471:                                                                                                  #  OTHERWISE U = -SCAXIS
020645,000472: 
020646,000473: 27,2130           57575                           VLOAD    VCOMP                                 
020647,000474: 27,2131           03765                                    SCAXIS                                
020648,000475: 27,2132           37270                           STCALL   COF                                   #  ROTATE ABOUT -SCAXIS
020649,000476: 27,2133           56137                                    CHEKAXIS                              
020650,000477: 27,2134           77775        U=SCAXIS           VLOAD                                          
020651,000478: 27,2135           03765                                    SCAXIS                                
020652,000479: 27,2136           03270                           STORE    COF                                   #  ROTATE ABOUT + SCAXIS
020653,000480: 27,2137           51545        CHEKAXIS           DLOAD    ABS                                   
020654,000481: 27,2140           03765                                    SCAXIS                                #  SEE IF WE ARE POINTING THE AOT
020655,000482: 27,2141           51025                           DSU      BPL                                   
020656,000483: 27,2142           14406                                    SINVEC2                               #  SIN 29.5 DEGS                         $2
020657,000484: 27,2143           56147                                    PICKANG1                              #  IF SO, ROTATE 50 DEGS ABOUT +- SCAXIS
020658,000485: 27,2144           52145                           DLOAD    GOTO                                  #  IF NOT, MUST BE POINTING THE TRANSPONDER
020659,000486: 27,2145           14412                                    VECANG2                               #  OR SOME VECTOR IN THE Y, OR Z PLANE
020660,000487: 27,2146           56151                                    COMPMFSN                              #  IN THIS CASE ROTATE 35 DEGS TO GET OUT
020661,000488:                                                                                                  #  OF GIMBAL LOCK (VECANG2 $360)
020662,000489: 27,2147           77745        PICKANG1           DLOAD                                          
020663,000490: 27,2150           14410                                    VECANG1                               #  = 50 DEGS                             $ 360
020664,000491: 27,2151           77624        COMPMFSN           CALL                                           
020665,000492: 27,2152           44527                                    DELCOMP                               #  COMPUTE THE ROTATION ABOUT SCAXIS TO
020666,000493: 27,2153           75160                           AXC,1    AXC,2                                 #  BRING MFS OUT OF GIMBAL LOCK
020667,000494: 27,2154           03245                                    MIS                                   
020668,000495: 27,2155           02230                                    KEL                                   
020669,000496: 27,2156           77624                           CALL                                           #  COMPUTE THE NEW TRANSFORMATION FROM
020670,000497: 27,2157           44312                                    MXM3                                  #  DESIRED S/C AXES TO STABLE MEMBER AXES
020671,000498:                                                                                                  #  WHICH WILL ALIGN VI WITH VF AND AVOID

Page 487

020673,000500:                                                                                                  #  GIMBAL LOCK
020674,000501: 27,2160           45160        FINDGIMB           AXC,1    CALL                                  
020675,000502: 27,2161           00000                                    0                                     #  EXTRACT THE COMMANDED CDU ANGLES FROM
020676,000503: 27,2162           44654                                    DCMTOCDU                              #  THIS MATRIX
020677,000504: 27,2163           40234                           RTB      SETPD                                 
020678,000505: 27,2164           21621                                    V1STO2S                               #  CONVERT TO 2:S COMPLEMENT
020679,000506: 27,2165           00001                                    0                                     
020680,000507: 27,2166           77650                           GOTO                                           
020681,000508: 27,2167           03324                                    VECQTEMP                              #  RETURN TO CALLER
020682,000509: 
020683,000510: 27,2170           50375        PICKAXIS           VLOAD    DOT                                   #  IF VF X VI = 0, FIND VF . VI
020684,000511: 27,2171           00035                                    28D                                   
020685,000512: 27,2172           03765                                    SCAXIS                                
020686,000513: 27,2173           72240                           BMN      TLOAD                                 
020687,000514: 27,2174           54354                                    ROT180                                
020688,000515: 27,2175           00032                                    25D                                   
020689,000516: 27,2176           77650                           GOTO                                           #  IF VF = VI, CDU DESIRED = PRESENT CDU
020690,000517: 27,2177           03324                                    VECQTEMP                              #  PRESENT CDU ANGLES
020691,000518: 
020692,000519: 35,2000                                           BANK     35                                    
020693,000520: 26,2000                                           SETLOC   MANUVER1                              
020694,000521: 26,2000                                           BANK                                           
020695,000522: 26,2354           47375        ROT180             VLOAD    VXV                                   #  IF VF, VI ANTIPARALLEL, 108 DEG ROTATION
020696,000523: 26,2355           03254                                    MIS        +6                         #  IS REQUIRED.  Y STABLE MEMBER AXIS IN
020697,000524: 26,2356           06522                                    HIDPHALF                              #  INITIAL S/C AXES.
020698,000525: 26,2357           47256                           UNIT     VXV                                   #  FIND Y(SM) X X(I)
020699,000526: 26,2360           03765                                    SCAXIS                                #  FIND UNIT(VI X UNIT(Y(SM) X X(I)))
020700,000527: 26,2361           40056                           UNIT     BOV                                   #  I.E. PICK A VECTOR IN THE PLANE OF X(I),
020701,000528: 26,2362           54376                                    PICKX                                 #  Y(SM) PERPENDICULAR TO VI
020702,000529: 26,2363           17270                           STODL    COF                                   
020703,000530: 26,2364           00045                                    36D                                   #  CHECK MAGNITUDE
020704,000531: 26,2365           50025                           DSU      BMN                                   #  OF THIS VECTOR.
020705,000532: 26,2366           14415                                    DPB-14                                #  IF LESS THAN B-14,
020706,000533: 26,2367           54376                                    PICKX                                 #  PICK X-AXIS.
020707,000534: 26,2370           77775                           VLOAD                                          
020708,000535: 26,2371           03270                                    COF                                   
020709,000536: 26,2372           17270        XROT               STODL    COF                                   
020710,000537: 26,2373           06522                                    HIDPHALF                              
020711,000538: 26,2374           77650                           GOTO                                           
020712,000539: 26,2375           56072                                    COMPMATX                              
020713,000540: 26,2376           52175        PICKX              VLOAD    GOTO                                  #  PICK THE XAXIS IN THIS CASE
020714,000541: 26,2377           06522                                    HIDPHALF                              
020715,000542: 26,2400           54372                                    XROT                                  
020716,000543: 26,2401           15555 35172  SINGIMLC           2DEC     .4285836003                            #  = SIN(59)                     $2
020717,000544: 26,2403           14113 36326  SINVEC1            2DEC     .3796356537                            #  = SIN(49.4)                   $2
020718,000545: 26,2405           07701 35703  SINVEC2            2DEC     .2462117800                            #  = SIN(29.5)                   $2
020719,000546: 26,2407           04343 21616  VECANG1            2DEC     .1388888889                            #  = 50 DEGREES                          $360

Page 488

020721,000548: 26,2411           03070 34344  VECANG2            2DEC     .09722222222                            #  = 35 DEGREES                          $360
020722,000549: 
020723,000550: 26,2413           00000        1BITDP             OCT      0                                     #  KEEP THIS BEFORE DPB(-14)     *********
020724,000551: 26,2414           00001        DPB-14             OCT      00001                                 
020725,000552: 26,2415           00000                           OCT      00000                                 
020726,000553: 

Page 489

020728,000555:                                                                                                  #  ROUTINE FOR INITIATING AUTOMATIC MANEUVER VIA KEYBOARD (V49)
020729,000556: 
020730,000557: 34,2000                                           BANK     34                                    
020731,000558: 23,2000                                           SETLOC   R62                                   
020732,000559: 23,2000                                           BANK                                           
020733,000560: 23,2103  E6,1675                                  EBANK=   BCDU                                  
020734,000561: 
020735,000562: 23,2103                                           COUNT*   $$/R62                                
020736,000563: 
020737,000564: 23,2103  23,2103               R62DISP            EQUALS   R62FLASH                              
020738,000565: 
020739,000566: 23,2103           35010        R62FLASH           CAF      V06N22                                #  FLASH V06N22 AND
020740,000567: 23,2104           04616                           TC       BANKCALL                              #  ICDU ANGLES
020741,000568: 23,2105           20477                           CADR     GOFLASH                               
020742,000569: 23,2106           15472                           TCF      ENDEXT                                #  TERMINATE
020743,000570: 23,2107           12111                           TCF      GOMOVE                                #  PROCEED
020744,000571: 23,2110           12103                           TCF      R62FLASH                              #  ENTER
020745,000572: 
020746,000573:                                                                                                  #  ASTRONAUT MAY LOAD NEW ICDUS AT THIS
020747,000574:                                                                                                  #  POINT
020748,000575: 23,2111           05504        GOMOVE             TC       UPFLAG                                #  SET FOR 3-AXIS MANEUVER
020749,000576: 23,2112           00124                           ADRES    3AXISFLG                              
020750,000577: 
020751,000578: 23,2113           04616                           TC       BANKCALL                              
020752,000579: 23,2114           54123                           CADR     R60LEM                                
020753,000580: 23,2115           15472                           TCF      ENDEXT                                #  END R62
020754,000581: 

End of include-file R60,R62.agc.  Parent file is MAIN.agc