Source Code

046888,000001: # Copyright: Public domain. 046889,000002: # Filename: PLANETARY_INERTIAL_ORIENTATION.agc 046890,000003: # Purpose: A section of Luminary 1C, revision 131. 046891,000004: # It is part of the source code for the Lunar Module's (LM) 046892,000005: # Apollo Guidance Computer (AGC) for Apollo 13 and Apollo 14. 046893,000006: # This file is intended to be a faithful transcription, except 046894,000007: # that the code format has been changed to conform to the 046895,000008: # requirements of the yaYUL assembler rather than the 046896,000009: # original YUL assembler. 046897,000010: # Reference: pp. 1139-1147 of 1729.pdf. 046898,000011: # Contact: Ron Burkey <info@sandroid.org>. 046899,000012: # Website: www.ibiblio.org/apollo/index.html 046900,000013: # Mod history: 06/01/03 RSB. Began transcribing. 046901,000014: # 05/14/05 RSB Corrected website reference above. 046902,000015: 046903,000016: # Page 1139 046904,000017: # PLANETARY INERTIAL ORIENTATION 046905,000018: 046906,000019: # ***** RP-TO-R SUBROUTINE ***** 046907,000020: # SUBROUTINE TO CONVERT RP (VECTOR IN PLANETARY COORDINATE SYSTEM, EITHER 046908,000021: # EARTH-FIXED OR MOON-FIXED) TO R (SAME VECTOR IN BASIC REF. SYSTEM) 046909,000022: # R = MT(T) * (RP + LP X RP) MT = M MATRIX TRANSPOSE 046910,000023: 046911,000024: # CALLING SEQUENCE 046912,000025: # L CALL 046913,000026: # L+1 RP-TO-R 046914,000027: 046915,000028: # SUBROUTINES USED 046916,000029: # EARTHMX, MOONMX, EARTHL 046917,000030: 046918,000031: # ITEMS AVAILABLE FROM LAUNCH DATA 046919,000032: # 504M = THE LIBRATION VECTOR L OF THE MOON AT TIME TIMSUBL, EXPRESSED 046920,000033: # IN THE MOON-FIXED COORD. SYSTEM RADIANS B0 046921,000034: 046922,000035: # ITEMS NECESSARY FOR SUBR. USED (SEE DESCRIPTION OF SUBR.) 046923,000036: 046924,000037: # INPUT 046925,000038: # MPAC = 0 FOR EARTH, NON-ZERO FOR MOON 046926,000039: # 0-5D = RP VECTOR 046927,000040: # 6-7D = TIME 046928,000041: 046929,000042: # OUTPUT 046930,000043: # MPAC = R VECTOR METERS B-29 FOR EARTH, B-27 FOR MOON 046931,000044: 046932,000045: 26,2000 SETLOC PLANTIN1 046933,000046: 26,2000 BANK 046934,000047: 046935,000048: 26,3716 COUNT* $$/LUROT 046936,000049: 046937,000050: 26,3716 46020 RP-TO-R STQ BHIZ 046938,000051: 26,3717 00050 RPREXIT 046939,000052: 26,3720 55733 RPTORA 046940,000053: 26,3721 77624 CALL # COMPUTE M MATRIX FOR MOON 046941,000054: 26,3722 51730 MOONMX # LP=LM FOR MOON RADIANS B0 046942,000055: 26,3723 77775 VLOAD 046943,000056: 26,3724 02013 504LM 046944,000057: 26,3725 53235 RPTORB VXV VAD 046945,000058: 26,3726 00001 504RPR 046946,000059: 26,3727 00001 504RPR 046947,000060: 26,3730 52105 VXM GOTO 046948,000061: 26,3731 00025 MMATRIX # MPAC=R=MT(T)*(RP+LPXRP) 046949,000062: 26,3732 51716 RPRPXXXX # RESET PUSHLOC TO 0 BEFORE EXITING 046950,000063: 26,3733 77624 RPTORA CALL # EARTH COMPUTATIONS 046951,000064: 26,3734 55743 EARTHMX # M MATRIX B-1 046952,000065: 26,3735 77624 CALL 046953,000066: 26,3736 15761 EARTHL # L VECTOR RADIANS B0 046954,000067: 26,3737 76521 MXV VSL1 # LP=M(T)*L RAD B-0 046955,000068: 26,3740 00025 MMATRIX 046956,000069: # Page 1140 046957,000070: 26,3741 77650 GOTO 046958,000071: 26,3742 55725 RPTORB 046959,000072: 24,2000 SETLOC PLANTIN 046960,000073: 24,2000 BANK 046961,000074: 24,3700 COUNT* $$/LUROT 046962,000075: 046963,000076: # Page 1141 046964,000077: # ***** R-TO-RP SUBROUTINE ***** 046965,000078: # SUBROUTINE TO CONVERT R (VECTOR IN REFERENCE COORD. SYSTEM) TO RP 046966,000079: # (VECTOR IN PLANETARY COORD SYSTEM) EITHER EARTH-FIXED OR MOON-FIXED 046967,000080: # RP = M(T) * (R - L X R) 046968,000081: 046969,000082: # CALLING SEQUENCE 046970,000083: # L CALL 046971,000084: # L+1 R-TO-RP 046972,000085: 046973,000086: # SUBROUTINES USED 046974,000087: # EARTHMX, MOONMX, EARTHL 046975,000088: 046976,000089: # INPUT 046977,000090: # MPAC = 0 FOR EARTH, NON-ZERO FOR MOON 046978,000091: # 0-5D = R VECTOR 046979,000092: # 6-7D = TIME 046980,000093: 046981,000094: # ITEMS AVAILABLE FROM LAUNCH DATA 046982,000095: # 504LM = THE LIBRATION VECTOR L OF THE MOON AT TIME TIMSUBL, EXPRESSED 046983,000096: # IN THE MOON-FIXED COORD. SYSTEM RADIANS B0 046984,000097: 046985,000098: # ITEMS NECESSARY FOR SUBROUTINES USED (SEE DESCRIPTION OF SUBR.) 046986,000099: 046987,000100: # OUTPUT 046988,000101: # MPAC = RP VECTOR METERS B-29 FOR EARTH, B-27 FOR MOON 046989,000102: 046990,000103: 24,3700 46020 R-TO-RP STQ BHIZ 046991,000104: 24,3701 00050 RPREXIT 046992,000105: 24,3702 51722 RTORPA 046993,000106: 24,3703 77624 CALL 046994,000107: 24,3704 51730 MOONMX 046995,000108: 24,3705 61375 VLOAD VXM 046996,000109: 24,3706 02013 504LM # LP=LM 046997,000110: 24,3707 00025 MMATRIX 046998,000111: 24,3710 77772 VSL1 # L = MT(T)*LP RADIANS B0 046999,000112: 24,3711 51235 RTORPB VXV BVSU 047000,000113: 24,3712 00001 504RPR 047001,000114: 24,3713 00001 504RPR 047002,000115: 24,3714 77721 MXV # M(T)*(R-LXR) B-2 047003,000116: 24,3715 00025 MMATRIX 047004,000117: 24,3716 40372 RPRPXXXX VSL1 SETPD 047005,000118: 24,3717 00001 0D 047006,000119: 24,3720 77650 GOTO 047007,000120: 24,3721 00050 RPREXIT 047008,000121: 24,3722 77624 RTORPA CALL # EARTH COMPUTATIONS 047009,000122: 24,3723 55743 EARTHMX 047010,000123: 24,3724 77624 CALL 047011,000124: 24,3725 15761 EARTHL 047012,000125: 24,3726 77650 GOTO # MPAC=L=(-AX,-AY,0) RAD B-0 047013,000126: 24,3727 51711 RTORPB 047014,000127: 047015,000128: # Page 1142 047016,000129: # ***** MOONMX SUBROUTINE ***** 047017,000130: # SUBROUTINE TO COMPUTE THE TRANSFORMATION MATRIX M FOR THE MOON 047018,000131: 047019,000132: # CALLING SEQUENCE 047020,000133: # L CALL 047021,000134: # L+1 MOONMX 047022,000135: 047023,000136: # SUBROUTINES USED 047024,000137: # NEWANGLE 047025,000138: 047026,000139: # INPUT 047027,000140: # 6-7D = TIME 047028,000141: 047029,000142: # ITEMS AVAILABLE FROM LAUNCH DATA 047030,000143: # BSUBO, BDOT 047031,000144: # TIMSUBO, NODIO, NODDOT, FSUBO, FDOT 047032,000145: # COSI = COS(I) B-1 047033,000146: # SINI = SIN(I) B-1 047034,000147: # I IS THE ANGLE BETWEEN THE MEAN LUNAR EQUATORIAL PLANE AND THE 047035,000148: # PLANE OF THE ECLIPTIC (1 DEGREE 32.1 MINUTES) 047036,000149: 047037,000150: # OUTPUT 047038,000151: # MMATRIX = 3X3 M MATRIX B-1 (STORED IN VAC AREA) 047039,000152: 047040,000153: 24,3730 40220 MOONMX STQ SETPD 047041,000154: 24,3731 00051 EARTHMXX 047042,000155: 24,3732 00011 8D 047043,000156: 24,3733 77770 AXT,1 # B REQUIRES SL 0, SL 5 IN NEWANGLE 047044,000157: 24,3734 00005 5 047045,000158: 24,3735 65345 DLOAD PDDL # PD 10D 8-9D=BSUBO 047046,000159: 24,3736 14017 BSUBO # 10-11D=BDOT 047047,000160: 24,3737 14011 BDOT 047048,000161: 24,3740 45006 PUSH CALL # PD 12D 047049,000162: 24,3741 53732 NEWANGLE # EXIT WITH PD 8D AND MPAC= B REVS B0 047050,000163: 24,3742 71406 PUSH COS # PD 10D 047051,000164: 24,3743 14041 STODL COB # PD 8D COS(B) B-1 047052,000165: 24,3744 77756 SIN # SIN(B) B-1 047053,000166: 24,3745 14043 STODL SOB # SETUP INPUT FOR NEWANGLE 047054,000167: 24,3746 14015 FSUBO # 8-9D=FSUBO 047055,000168: 24,3747 41525 PDDL PUSH # PD 10D THEN 12D 10-11D=FDOT 047056,000169: 24,3750 14007 FDOT 047057,000170: 24,3751 45170 AXT,1 CALL # F REQUIRES SL 1, SL 6 IN NEWANGLE. 047058,000171: 24,3752 00004 4 047059,000172: 24,3753 53732 NEWANGLE # EXIT WITH PD 8D AND MPAC= F REVS B0 047060,000173: 24,3754 14027 STODL AVECTR +2 # SAVE F TEMP 047061,000174: 24,3755 14013 NODIO # 8-9D=NODIO 047062,000175: 24,3756 41525 PDDL PUSH # PD 10D THEN 12D 10-11D=NODDOT 047063,000176: 24,3757 14005 NODDOT # MPAC=5 047064,000177: 24,3760 45170 AXT,1 CALL # NODE REQUIRES SL 0, SL 5 IN NEWANGLE 047065,000178: 24,3761 00005 5 047066,000179: 24,3762 53732 NEWANGLE # EXIT WITH PD 8D AND MPAC= NODI REVS B0 047067,000180: # Page 1143 047068,000181: 24,3763 71406 PUSH COS # PD 10D 8-9D= NODI REVS B0 047069,000182: 24,3764 77606 PUSH # PD 12D 10-11D= COS(NODI) B-1 047070,000183: 24,3765 00025 STORE AVECTR 047071,000184: 24,3766 76405 DMP SL1R 047072,000185: 24,3767 00041 COB # COS(NODI) B-1 047073,000186: 24,3770 14035 STODL BVECTR +2 # PD 10D 20-25D=AVECTR=COB*SIN(NODI) 047074,000187: 24,3771 76405 DMP SL1R # SOB*SIN(NODI) 047075,000188: 24,3772 00043 SOB 047076,000189: 24,3773 14037 STODL BVECTR +4 # PD 8D 047077,000190: 24,3774 41556 SIN PUSH # -SIN(NODI) B-1 047078,000191: 24,3775 52076 DCOMP GOTO # 26-31D=BVECTR=COV*COS(NODI) 047079,000192: 24,3776 53653 MOONMXA 047080,000193: 047081,000194: 25,3653 BANK 25 047082,000195: 25,2000 SETLOC PLANTIN3 047083,000196: 25,2000 BANK 047084,000197: 25,3653 COUNT* $$/LUROT 047085,000198: 047086,000199: 25,3653 14033 MOONMXA STODL BVECTR # PD 8D SOB*COS(NODI) 047087,000200: 25,3654 00027 AVECTR +2 # MOVE F FROM TEMP LOC. TO 504F 047088,000201: 25,3655 14007 STODL 504F 047089,000202: 25,3656 76405 DMP SL1R 047090,000203: 25,3657 00041 COB 047091,000204: 25,3660 14027 STODL AVECTR +2 047092,000205: 25,3661 00011 SINNODI # 8-9D=SIN(NODI) B-1 047093,000206: 25,3662 76405 DMP SL1R 047094,000207: 25,3663 00043 SOB 047095,000208: 25,3664 14031 STODL AVECTR +4 # 0 047096,000209: 25,3665 06524 HI6ZEROS # 8-13D= CVECTR= -SOB B-1 047097,000210: 25,3666 57525 PDDL DCOMP # PD 10D COB 047098,000211: 25,3667 00043 SOB 047099,000212: 25,3670 63325 PDDL PDVL # PD 12D THEN PD 14D 047100,000213: 25,3671 00041 COB 047101,000214: 25,3672 00033 BVECTR 047102,000215: 25,3673 63361 VXSC PDVL # PD 20D BVECTR*SINI B-2 047103,000216: 25,3674 14003 SINI 047104,000217: 25,3675 00011 CVECTR 047105,000218: 25,3676 53361 VXSC VAD # PD 14D CVECTR*COSI B-2 047106,000219: 25,3677 14001 COSI 047107,000220: 25,3700 77772 VSL1 047108,000221: 25,3701 24041 STOVL MMATRIX +12D # PD 8D M2=BVECTR*SINI+CVECTR*COSI B-1 047109,000222: 25,3702 63361 VXSC PDVL # PD 14D 047110,000223: 25,3703 14003 SINI # CVECTR*SINI B-2 047111,000224: 25,3704 00033 BVECTR 047112,000225: 25,3705 52361 VXSC VSU # PD 8D BVECTR*COSI B-2 047113,000226: 25,3706 14001 COSI 047114,000227: 25,3707 65372 VSL1 PDDL # PD 14D 047115,000228: 25,3710 00007 504F # 8-13D=DVECTR=BVECTR*COSI-CVECTR*SINI B-1 047116,000229: 25,3711 74346 COS VXSC 047117,000230: 25,3712 00011 DVECTR 047118,000231: 25,3713 73525 PDDL SIN # PD 20D 14-19D= DVECTR*COSF B-2 047119,000232: # Page 1144 047120,000233: 25,3714 00007 504F 047121,000234: 25,3715 52361 VXSC VSU # PD 14D AVECTR*SINF B-2 047122,000235: 25,3716 00025 AVECTR 047123,000236: 25,3717 77772 VSL1 047124,000237: 25,3720 14033 STODL MMATRIX +6 # M1= AVECTR*SINF-DVECTR*COSF B-1 047125,000238: 25,3721 00007 504F 047126,000239: 25,3722 74356 SIN VXSC # PD 8D 047127,000240: 25,3723 71525 PDDL COS # PD 14D 8-13D=DVECTR*SINF B-2 047128,000241: 25,3724 00007 504F 047129,000242: 25,3725 53361 VXSC VAD # PD 8D AVECTR*COSF B-2 047130,000243: 25,3726 00025 AVECTR 047131,000244: 25,3727 57572 VSL1 VCOMP 047132,000245: 25,3730 34025 STCALL MMATRIX # M0= -(AVECTR*COSF+DVECTR*SINF) B-1 047133,000246: 25,3731 00051 EARTHMXX 047134,000247: 047135,000248: # COMPUTE X=X0+(XDOT)(T+T0) 047136,000249: # 8-9D= X0 (REVS B-0), PUSHLOC SET AT 12D 047137,000250: # 10-11D=XDOT (REVS/CSEC) SCALED B+23 FOR WEARTH,B+28 FOR NODDOT AND BDOT 047138,000251: # AND B+27 FOR FDOT 047139,000252: # X1=DIFFERENCE IN 23 AND SCALING OF XDOT, =0 FOR WEARTH, 5 FOR NDDOT AND 047140,000253: # BDOT AND 4 FOR FDOT 047141,000254: # 6-7D=T (CSEC B-28), TIMSUBO= (CSEC B-42 TRIPLE PREC.) 047142,000255: 047143,000256: 25,3732 54345 NEWANGLE DLOAD SR # ENTER PD 12D 047144,000257: 25,3733 00007 6D 047145,000258: 25,3734 20617 14D 047146,000259: 25,3735 72371 TAD TLOAD # CHANGE MODE TO TP 047147,000260: 25,3736 01707 TIMSUBO 047148,000261: 25,3737 00155 MPAC 047149,000262: 25,3740 14017 STODL TIMSUBM # T+T0 CSEC B-42 047150,000263: 25,3741 00020 TIMSUBM +1 047151,000264: 25,3742 77605 DMP # PD 10D MULT BY XDOT IN 10-11D 047152,000265: 25,3743 43257 SL* DAD # PD 8D ADD X0 IN 8-9D AFTER SHIFTING 047153,000266: 25,3744 20206 5,1 # SUCH THAT SCALING IS B-0 047154,000267: 25,3745 67206 PUSH SLOAD # PD 10D SAVE PARTIAL (X0+XDOT*T) IN 8-9D 047155,000268: 25,3746 00017 TIMSUBM 047156,000269: 25,3747 41261 SL DMP 047157,000270: 25,3750 20212 9D 047158,000271: 25,3751 00013 10D # XDOT 047159,000272: 25,3752 43257 SL* DAD # PD 8D SHIFT SUCH THAT THIS PART OF X 047160,000273: 25,3753 20213 10D,1 # IS SCALED REVS/CSEC B-0 047161,000274: 25,3754 77600 BOV # TURN OFF OVERFLOW IF SET BY SHIFT 047162,000275: 25,3755 53756 +1 # INSTRUCTION BEFORE EXITING. 047163,000276: 25,3756 77616 RVQ # MPAC=X= X0+(XDOT)(T+T0) REVS B0 047164,000277: 047165,000278: # Page 1145 047166,000279: # ***** EARTHMX SUBROUTINE ***** 047167,000280: # SUBROUTINE TO COMPUTE THE TRANSFORMATION MATRIX M FOR THE EARTH 047168,000281: 047169,000282: # CALLING SEQUENCE 047170,000283: # L CALL 047171,000284: # L+1 EARTHMX 047172,000285: 047173,000286: # SUBROUTINE USED 047174,000287: # NEWANGLE 047175,000288: 047176,000289: # INPUT 047177,000290: # INPUT AVAILABLE FROM LAUNCH DATA AZC REVS B-0 047178,000291: # TEPHEM CSEC B-42 047179,000292: # 6-7D= TIME CSEC B-28 047180,000293: 047181,000294: # OUTPUT 047182,000295: # MMATRIX= 3X3 M MATRIX B-1 (STORED IN VAC AREA) 047183,000296: 047184,000297: 26,3743 BANK 26 047185,000298: 26,2000 SETLOC PLANTIN1 047186,000299: 26,2000 BANK 047187,000300: 26,3743 COUNT* $$/LUROT 047188,000301: 047189,000302: 26,3743 40220 EARTHMX STQ SETPD # SET 8-9D=AZO 047190,000303: 26,3744 00051 EARTHMXX 047191,000304: 26,3745 00011 8D # 10-11D=WEARTH 047192,000305: 26,3746 77770 AXT,1 # FOR SL 5, AND SL 10 IN NEWANGLE 047193,000306: 26,3747 00000 0 047194,000307: 26,3750 65345 DLOAD PDDL # LEAVING PD SET AT 12D FOR NEWANGLE 047195,000308: 26,3751 01712 AZO 047196,000309: 26,3752 14021 WEARTH 047197,000310: 26,3753 45006 PUSH CALL 047198,000311: 26,3754 53732 NEWANGLE 047199,000312: 26,3755 41401 SETPD PUSH # 18-19D=504AZ 047200,000313: 26,3756 00023 18D # COS(AZ) SIN(AZ) 0 047201,000314: 26,3757 65346 COS PDDL # 20-37D= MMATRIX= -SIN(AZ) COS(AZ) 0 B-1 047202,000315: 26,3760 00023 504AZ # 0 0 1 047203,000316: 26,3761 65356 SIN PDDL 047204,000317: 26,3762 06524 HI6ZEROS 047205,000318: 26,3763 73525 PDDL SIN 047206,000319: 26,3764 00023 504AZ 047207,000320: 26,3765 65276 DCOMP PDDL 047208,000321: 26,3766 00023 504AZ 047209,000322: 26,3767 63346 COS PDVL 047210,000323: 26,3770 06524 HI6ZEROS 047211,000324: 26,3771 41525 PDDL PUSH 047212,000325: 26,3772 06522 HIDPHALF 047213,000326: 26,3773 77650 GOTO 047214,000327: 26,3774 00051 EARTHMXX 047215,000328: 047216,000329: # Page 1146 047217,000330: # ***** EARTH SUBROUTINE ***** 047218,000331: # SUBROUTINE TO COMPUTE L VECTOR FOR EARTH 047219,000332: 047220,000333: # CALLING SEQUENCE 047221,000334: # L CALL 047222,000335: # L+1 EARTHL 047223,000336: 047224,000337: # INPUT 047225,000338: # AXO,AYO SET AT LAUNCH TIME WITH AYO IMMEDIATELY FOLLOWING AXO IN CORE 047226,000339: 047227,000340: # OUTPUT 047228,000341: # -AX 047229,000342: # MPAC= -AY RADIANS B-0 047230,000343: # 0 047231,000344: 047232,000345: 06,3761 BANK 06 047233,000346: 06,2000 SETLOC EARTHLOC 047234,000347: 06,2000 BANK 047235,000348: 06,3761 COUNT* $$/LUROT 047236,000349: 047237,000350: 06,3761 57545 EARTHL DLOAD DCOMP 047238,000351: 06,3762 01716 AXO 047239,000352: 06,3763 14017 STODL 504LPL 047240,000353: 06,3764 01714 -AYO 047241,000354: 06,3765 14021 STODL 504LPL +2 047242,000355: 06,3766 24007 LO6ZEROS 047243,000356: 06,3767 24023 STOVL 504LPL +4 047244,000357: 06,3770 00017 504LPL 047245,000358: 06,3771 77616 RVQ 047246,000359: 047247,000360: # Page 1147 047248,000361: # CONSTANTS AND ERASABLE ASSIGNMENTS 047249,000362: 047250,000363: 06,3772 12,2004 1B1 = DP1/2 # 1 SCALED B-1 047251,000364: 06,3772 0000050 RPREXIT = S1 # R-TO-RP AND RP-TO-R SUBR EXIT 047252,000365: 06,3772 0000051 EARTHMXX = S2 # EARTHMX, MOONMX SUBR. EXITS 047253,000366: 06,3772 504RPR = 0D # 6 REGS R OR RP VECTOR 047254,000367: 06,3772 SINNODI = 8D # 2 SIN(NODI) 047255,000368: 06,3772 DVECTR = 8D # 6 D VECTOR MOON 047256,000369: 06,3772 CVECTR = 8D # 6 C VECTR MOON 047257,000370: 06,3772 504AZ = 18D # 2 AZ 047258,000371: 06,3772 TIMSUBM = 14D # 3 TIME SUB M (MOON) T+10 IN GETAZ 047259,000372: 06,3772 504LPL = 14D # 6 L OR LP VECTOR 047260,000373: 06,3772 AVECTR = 20D # 6 A VECTOR (MOON) 047261,000374: 06,3772 BVECTR = 26D # 6 B VECTOR (MOON) 047262,000375: 06,3772 MMATRIX = 20D # 18 M MATRIX 047263,000376: 06,3772 COB = 32D # 2 COS(B) B-1 047264,000377: 06,3772 SOB = 34D # 2 SIN(B) B-1 047265,000378: 06,3772 504F = 6D # 2 F(MOON) 047266,000379: End of include-file PLANETARY_INERTIAL_ORIENTATION.agc. Parent file is MAIN.agc