Source Code

013250,000001: 013251,000002: 013252,000003: 013253,000004: 013254,000005: 013255,000006: 013256,000007: 013257,000008: 013258,000009: 013259,000010: 013260,000011: 013261,000012: 013262,000013: 013263,000014: 013264,000015: 013265,000016: 013266,000017: 23,2041 013267,000018: 13,2000 013268,000019: 13,2000 013269,000020: 013270,000021: 13,2070 30,2000 013271,000022: 13,2070 E5,1642 013272,000023: 013273,000024: 013274,000025: 013275,000026: 013276,000027: 013277,000028: 013278,000029: 013279,000030: 013280,000031: 013281,000032: 013282,000033: 013283,000034: 013284,000035: 013285,000036: 013286,000037: 013287,000038: 013288,000039: 013289,000040: 013290,000041: 013291,000042: 13,2070 < 013414,000165: 23,2055 013415,000166: 23,2056 013416,000167: 23,2057 013417,000168: 013418,000169: 23,2060 013419,000170: 23,2061 013420,000171: 23,2062 013421,000172: 23,2063 013422,000173: 23,2064 013423,000174: 013424,000175: 013425,000176: # Copyright: Public domain. # Filename: LEM_GEOMETRY.agc # Purpose: A section of Luminary 1C, revision 131. # It is part of the source code for the Lunar Module's (LM) # Apollo Guidance Computer (AGC) for Apollo 13 and Apollo 14. # This file is intended to be a faithful transcription, except # that the code format has been changed to conform to the # requirements of the yaYUL assembler rather than the # original YUL assembler. # Reference: pp. 327-332 of 1729.pdf. # Contact: Ron Burkey <info@sandroid.org>. # Website: www.ibiblio.org/apollo/index.html # Mod history: 05/10/03 RSB. Began transcribing. # 05/14/05 RSB Corrected website reference above. # Page 327 BANK 23 SETLOC LEMGEOM BANK SBANK= LOWSUPER EBANK= XSM # THESE TWO ROUTINES COMPUTE THE ACTUAL STATE VECTOR FOR LM,CSM BY ADDING # THE CONIC R,V AND THE DEVIATIONS R,V. THE STATE VECTORS ARE CONVERTED TO # METERS B-29 AND METERS/CSEC B-7 AND STORED APPROPIRATELY IN RN,VN OR # R-OTHER,V-OTHER FOR DOWNLINK. THE ROUTINES' NAMES ARE SWITCHED IN THE # OTHER VEHICLE'S COMPUTER. # INPUT # STATE VECTOR IN TEMPORARY STORAGE AREA # IF STATE VECTOR IS SCALED POS B27 AND VEL B5 # SET X2 TO +2 # IF STATE VECTOR IS SCALED POS B29 AND VEL B7 # SET X2 TO 0 # OUTPUT # R(T) IN RN, V(T) IN VN, T IN PIPTIME # OR # R(T) IN R-OTHER, V(T) IN V-OTHER (T IS DEFINED BY T-OTHER) COUNT* $$/GEOM >013292,000043: 13,2070 43414 SVDWN2 BOF RVQ # SW=1=AVETOMID DOING W-MATRIX INTEG. 04756 AVEMIDSW 26073 +1 53775 VLOAD VSL* 01521 TDELTAV 57605 0 -7,2 53655 VAD VSL* 01535 RCV 57576 0,2 25220 STOVL RN 01527 TNUV 53257 VSL* VAD 57602 0 -4,2 01543 VCV 77657 VSL* 57576 0,2 15226 STODL VN 01517 TET 01234 STORE PIPTIME 77616 RVQ # Page 328 >013313,000064: 13,2114 53775 SVDWN1 VLOAD VSL* 01521 TDELTAV 57605 0 -7,2 53655 VAD VSL* 01535 RCV 57576 0,2 25720 STOVL R-OTHER 01527 TNUV 53257 VSL* VAD 57602 0 -4,2 01543 VCV 77657 VSL* 57576 0,2 01726 STORE V-OTHER 77616 RVQ # Page 329 # THE FOLLOWING ROUTINE TAKES A HALF UNIT TARGET VECTOR REFERRED TO NAV BASE COORDINATES AND FINDS BOTH # GIMBAL ORIENTATIONS AT WHICH THE RR MIGHT SIGHT THE TARGET. THE GIMBAL ANGLES CORRESPONDING TO THE PRESENT MODE # ARE LEFT IN MODEA AND THOSE WHICH WOULD BE USED AFTER A REMODE IN MODEB. THIS ROUTINE ASSUMES MODE 1 IS TRUNNION # ANGLE LESS THAN 90 DEGS IN ABS VALUE WITH ARBITRARY SHAFT, WITH A CORRESPONDING DEFINITION FOR MODE 2. MODE # SELECTION AND LIMIT CHECKING ARE DONE ELSEWHERE. # THE MODE 1 CONFIGURATION IS CALCULATED FROM THE VECTOR AND THEN MODE 2 IS FOUND USING THE RELATIONS # S(2) = 180 + S(1) # T(2) = 180 - T(1) # THE VECTOR ARRIVES IN MPAC WHERE TRG*SMNG OR *SMNB* WILL HAVE LEFT IT. 553">013343,000094: 13,2133 00041 RRANGLES STORE 32D 57545 DLOAD DCOMP # SINCE WE WILL FIND THE MODE 1 SHAFT 00043 34D # ANGLE LATER, WE CAN FIND THE MODE 1 67401 SETPD ASIN # TRUNNION BY SIMPLY TAKING THE ARCSIN OF 00001 0 # THE Y COMPONENT, THE ASIN GIVIN AN 44206 PUSH BDSU # ANSWER WHOSE ABS VAL IS LESS THAN 90 DEG. 24005 LODPHALF 14005 STODL 4 # MODE 2 TRUNNION TO 4. 24007 LO6ZEROS 24043 STOVL 34D # UNIT THE PROJECTION OF THE VECTOR 00041 32D # IN THE X-Z PLANE 41056 UNIT BOVB # IF OVERFLOW, TARGET VECTOR IS ALONG Y 52432 LUNDESCH # CALL FOR MANEUVER UNLESS ON LUNAR SURF 14041 STODL 32D # PROJECTION VECTOR. 00041 32D 44142 SR1 STQ 00051 S2 14023 STODL SINTH # USE ARCTRIG SINCE SHAFT COULD BE ARG. 00045 36D 77742 SR1 34021 STCALL COSTH 47322 ARCTRIG # Page 331 43206 PUSH DAD # MODE 1 SHAFT TO 2. 24005 LODPHALF 24007 STOVL 6 00005 4 77634 RTB # FIND MODE 2 CDU ANGLES. 21636 2V1STO2S 25111 STOVL MODEB 00001 0 77634 RTB # MODE 1 ANGLES TO MODE A. 21636 2V1STO2S 01107 STORE MODEA 77776 EXIT 40110 CS RADMODES # SWAP MODEA AND MODEB IF RR IN MODE 2. 74740 MASK ANTENBIT 10000 CCS A 12204 TCF +4 53107 DXCH MODEA 53111 DXCH MODEB 53107 DXCH MODEA 06042 TC INTPRET 77650 GOTO 00051 S2 # Page 331 # GIVEN RR TRUNNION AND SHAFT (T,S) IN TANGNB,+1, FIND THE ASSOCIATED # LINE OF SIGHT IN NAV BASE AXES. THE HALF UNIT VECTOR, .5(SIN(S)COS(T), # -SIN(T),COS(S)COS(T)) IS LEFT IN MPAC AND 32D. SETLOC INFLIGHT BANK COUNT* $$/GEOM >013401,000152: 23,2041 47135 RRNB SLOAD RTB 03753 TANGNB 21577 CDULOGIC 41401 SETPD PUSH # TRUNNION ANGLE TO 0 00001 0 57556 SIN DCOMP 14043 STODL 34D # Y COMPONENT 41546 COS PUSH # .5 COS(T) TO 0 47135 SLOAD RTB 03754 TANGNB +1 21577 CDULOGIC /a>013413,000164: 23,2054 71406 RRNB1 PUSH COS # SHAFT ANGLE TO 2 72405 DMP SL1 00001 0 14045 STODL 36D # Z COMPONENT 41356 SIN DMP 77752 SL1 24041 STOVL 32D 00041 32D 77616 RVQ # THIS ENTRY TO RRNB REQUIRES THE TRUNNION AND SHAFT ANGLES IN MPAC AND MPAC +1 RESPECTIVELY 143">013426,000177: 23,2065 14025 RRNBMPAC STODL 20D # SAVE SHAFT CDU IN 21. 00155 MPAC # SET MODE TO DP. (THE PRECEEDING STORE # MAY BE DP, TP OR VECTOR.) 40234 RTB SETPD 21577 CDULOGIC 00001 0 73406 PUSH SIN # TRUNNION ANGLE TO 0 77676 DCOMP 14043 STODL 34D # Y COMPONENT 41546 COS PUSH # .5COS(T) TO 0 47135 SLOAD RTB # PICK UP CDU'S. 00026 21D 21577 CDULOGIC 77650 GOTO 46054 RRNB1 # Page 332 # (This page has nothing on it.) LEM_GEOMETRY.agc. Parent file is MAIN.agc