GAP: ASSEMBLE REVISION 131 OF AGC PROGRAM LUMINARY BY NASA 2021112-091 17:53 DEC. 19, 1969Note 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.
Source Code
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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, 1969Note 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. |
020183,000002: ## Copyright: Public domain.
020184,000003: ## Filename: R60_62.agc
020185,000004: ## Purpose: A section of Luminary 1C, revision 131.
020186,000005: ## It is part of the source code for the Lunar Module's (LM)
020187,000006: ## Apollo Guidance Computer (AGC) for Apollo 13.
020188,000007: ## This file is intended to be a faithful transcription, except
020189,000008: ## that the code format has been changed to conform to the
020190,000009: ## requirements of the yaYUL assembler rather than the
020191,000010: ## original YUL assembler.
020192,000011: ## Reference: pp. 476-489
020193,000012: ## Contact: Ron Burkey <info@sandroid.org>.
020194,000013: ## Website: www.ibiblio.org/apollo/index.html
020195,000014: ## Mod history: 05/14/03 RSB. Began transcribing.
020196,000015: ## 05/14/05 RSB Corrected website reference above.
020197,000016: ## 2017-01-06 RSB Page numbers now agree with those on the
020198,000017: ## original harcopy, as opposed to the PDF page
020199,000018: ## numbers in 1701.pdf.
020200,000019: ## 2017-01-27 RSB Back-ported a comment-text fix identified in Luminary 69.
020201,000020: ## 2017-02-23 RSB Proofed comment text using octopus/ProoferComments.
020202,000021: ## 2017-02-28 RSB Fixed lingering typos.
020203,000022: ## 2017-03-09 RSB Comment text fixes noted in proofing Luminary 116.
020204,000023:
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Page 476 |
020206,000025: # MOD NO: 0 DATE: 1 MAY 1968
020207,000026: # MOD BY: DIGITAL DEVEL GROUP LOG SECTION R60,R62
020208,000027:
020209,000028: # FUNCTIONAL DESCRIPTION:
020210,000029:
020211,000030: # CALLED AS A GENERAL SUBROUTINE TO MANEUVER THE LM TO A SPECIFIED
020212,000031: # ATTITUDE.
020213,000032:
020214,000033: # 1. IF THE 3-AXIS FLAG IS NOT SET THE FINAL CDU ANGLES ARE
020215,000034: # CALCULATED (VECPOINT).
020216,000035:
020217,000036: # 2. THE FDAI BALL ANGLES (NOUN 18) ARE CALCULATED (BALLANGS).
020218,000037:
020219,000038: # 3. REQUEST FLASHING DISPLAY V50 N18 PLEASE PERFORM AUTO MANEUVER.
020220,000039:
020221,000040: # 4. IF PRIORITY DISPLAY FLAG IS SET DO A PHASECHANGE. THEN AWAIT
020222,000041: # ASTRONAUT RESPONSE.
020223,000042:
020224,000043: # 5. DISPLAY RESPONSE RETURNS:
020225,000044:
020226,000045: # A. ENTER - RESET 3-AXIS FLAG AND RETURN TO CLIENT.
020227,000046:
020228,000047: # B. TERMINATE - IF IN P00 GO TO STEP 5A. OTHERWISE CHECK IF R61 IS
020229,000048: # THE CALLING PROGRAM. IF IN R61 AN EXIT IS MADE TO GOTOV56. IF
020230,000049: # NOT IN R61 AN EXIT IS DONE VIA GOTOP00H.
020231,000050:
020232,000051: # C. PROCEED - CONTINUE WITH PROGRAM AT STEP 6.
020233,000052:
020234,000053: # 6. IF THE 3-AXIS FLAG IS NOT SET, THE FINAL CDU ANGLES ARE CALCULATED
020235,000054: # (VECPOINT).
020236,000055:
020237,000056: # 7. THE FDAI BALL ANGLES (NOUN 18) ARE CALCULATED (BALLANGS).
020238,000057:
020239,000058: # 8. IF THE G+N SWITCH IS NOT SET GO BACK TO STEP 3.
020240,000059: #
020241,000060: # 9. IF THE AUTO SWITCH IS NOT SET GO BACK TO STEP 3.
020242,000061:
020243,000062: # 10. NONFLASHING DISPLAY V06N18 (FDAI ANGLES).
020244,000063:
020245,000064: # 11. DO A PHASECHANGE.
020246,000065:
020247,000066: # 12. DO A MANEUVER CALCULATION AND ICDU DRIVE ROUTINE TO ACHIEVE FINAL
020248,000067: # GIMBAL ANGLES (GOMANUR).
020249,000068:
020250,000069: # 13. AT END OF MANEUVER GO TO STEP 3.
020251,000070:
020252,000071: # IF SATISFACTORY MANEUVER STEP 5A EXITS R60.
020253,000072: # FOR FURTHER ADJUSTMENT OF THE VEHICLE ATTITUDE ABOUT THE
020254,000073: # DESIRED VECTOR, THE ROUTINE MAY BE PERFORMED AGAIN STARTING AT
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Page 477 |
020256,000075: # STEP 5C.
020257,000076:
020258,000077: # CALLING SEQUENCE: TC BANKCALL
020259,000078: # CADR R60LEM
020260,000079:
020261,000080: # ERASABLE INITIALIZATION REQUIRED: SCAXIS, POINTVSM (FOR VECPOINT)
020262,000081: # 3AXISFLG.
020263,000082:
020264,000083: # SUBROUTINES CALLED: VECPOINT, BALLANGS, GOPERF2R, LINUS, GODSPER,
020265,000084: # GOMANUR, DOWNFLAG, PHASCHNG, UPFLAG
020266,000085:
020267,000086: # NORMAL EXIT MODES: CAE TEMPR60 (CALLERS RETURN ADDRESS)
020268,000087: # TC BANKJUMP
020269,000088:
020270,000089: # ALARMS: NONE
020271,000090:
020272,000091: # OUTPUT: NONE
020273,000092:
020274,000093: # DEBRIS: CPHI, CTHETA, CPSI, 3AXISFLG, TBASE2
020275,000094:
020276,000095: 34,2000 BANK 34
020277,000096: 26,2000 SETLOC MANUVER
020278,000097: 26,2000 BANK
020279,000098:
020280,000099: 26,2123 1163 EBANK= TEMPR60
020281,000100:
020282,000101: 26,2123 COUNT* $$/R06
020283,000102: 26,2123 04645 R60LEM TC MAKECADR
020284,000103: 26,2124 55163 TS TEMPR60
020285,000104:
020286,000105: 26,2125 34746 REDOMANN CAF 3AXISBIT
020287,000106: 26,2126 70101 MASK FLAGWRD5 # IS 3-AXIS FLAG SET
020288,000107: 26,2127 10000 CCS A
020289,000108: 26,2130 12136 TCF TOBALL # YES
020290,000109: 26,2131 06042 TC INTPRET
020291,000110: 26,2132 77624 CALL
020292,000111: 26,2133 56040 VECPOINT # TO COMPUTE FINAL ANGLES
020293,000112: 26,2134 00322 STORE CPHI # STORE FINAL ANGLES - CPHI, CTHETA, CPSI
020294,000113: 26,2135 77776 EXIT
020295,000114:
020296,000115: 26,2136 05504 TOBALL TC UPFLAG # INSURE THAT TOTAL ATTITUDE ERRORS ARE
020297,000116: 26,2137 00013 ADRES NEEDLFLG # DISPLAYED ON FDAI ERROR NEEDLES
020298,000117: 26,2140 05516 TC DOWNFLAG
020299,000118: 26,2141 00000 ADRES NEED2FLG
020300,000119: 26,2142 04616 TC BANKCALL
020301,000120: 26,2143 54272 CADR BALLANGS # TO CONVERT ANGLES TO FDAI
020302,000121: 26,2144 32260 TOBALLA CAF V06N18
020303,000122: 26,2145 04616 TC BANKCALL
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Page 478 |
020305,000124: 26,2146 20711 CADR GOPERF2R # DISPLAY PLEASE PERFORM AUTO MANEUVER
020306,000125: 26,2147 02246 TC R61TEST
020307,000126: 26,2150 02154 TC REDOMANC # PROCEED
020308,000127: 26,2151 02201 TC ENDMANU1 # ENTER I.E. FINISHED WITH R60
020309,000128: 26,2152 02205 TC CHKLINUS # TO CHECK FOR PRIORITY DISPLAYS
020310,000129: 26,2153 05155 TC ENDOFJOB
020311,000130:
020312,000131: 26,2154 34746 REDOMANC CAF 3AXISBIT
020313,000132: 26,2155 70101 MASK FLAGWRD5 # IS 3-AXIS FLAG SET
020314,000133: 26,2156 10000 CCS A
020315,000134: 26,2157 12165 TCF TOBALLC # YES
020316,000135: 26,2160 06042 TC INTPRET
020317,000136: 26,2161 77624 CALL
020318,000137: 26,2162 56040 VECPOINT # TO COMPUTE FINAL ANGLES
020319,000138: 26,2163 00322 STORE CPHI # STORE ANGLES
020320,000139: 26,2164 77776 EXIT
020321,000140:
020322,000141: 26,2165 04616 TOBALLC TC BANKCALL
020323,000142: 26,2166 54272 CADR BALLANGS # TO CONVERT ANGLES TO FDAI
020324,000143: 26,2167 02261 TC G+N,AUTO # CHECK AUTO MODE
020325,000144: 26,2170 10000 CCS A
020326,000145: 26,2171 12144 TCF TOBALLA # NOT AUTO, GO REREQUEST AUTO MANEUVER.
020327,000146:
020328,000147: 26,2172 32260 AUTOMANV CAF V06N18 # STATIC DISPLAY DURING AUTO MANEUVER
020329,000148: 26,2173 04616 TC BANKCALL # -
020330,000149: 26,2174 20452 CADR GODSPR # -
020331,000150: 26,2175 02205 TC CHKLINUS # TO CHECK FOR PRIORITY DISPLAYS
020332,000151:
020333,000152: 26,2176 04616 STARTMNV TC BANKCALL # PERFORM MANEUVER VIA KALCMANU
020334,000153: 26,2177 17741 CADR GOMANUR
020335,000154:
020336,000155: 26,2200 12144 ENDMANUV TCF TOBALLA # FINISHED MANEUVER.
020337,000156: 26,2201 05516 ENDMANU1 TC DOWNFLAG # RESET 3-AXIS FLAG
020338,000157: 26,2202 00124 ADRES 3AXISFLG
020339,000158: 26,2203 31163 CAE TEMPR60 # -
020340,000159: 26,2204 04640 TC BANKJUMP # -
020341,000160:
020342,000161: 26,2205 40100 CHKLINUS CS FLAGWRD4
020343,000162: 26,2206 74740 MASK PDSPFBIT # IS PRIORITY DISPLAY FLAG SET?
020344,000163: 26,2207 10000 CCS A # -
020345,000164: 26,2210 00002 TC Q # NO - EXIT
020346,000165: 26,2211 30002 CA Q
020347,000166: 26,2212 54156 TS MPAC +2 # SAVE RETURN
020348,000167: 26,2213 46250 CS THREE # OBTAIN LOCATION FOR RESTART
020349,000168: 26,2214 60133 AD BUF2 # HOLDS Q OF LAST DISPLAY
020350,000169: 26,2215 55054 TS TBASE2
020351,000170:
020352,000171: 26,2216 05353 TC PHASCHNG
020353,000172: 26,2217 00132 OCT 00132
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Page 479 |
020355,000174: 26,2220 34745 CAF BIT7
020356,000175: 26,2221 05464 TC LINUS # GO SET BITS FOR PRIORITY DISPLAY -
020357,000176: 26,2222 00156 TC MPAC +2
020358,000177:
020359,000178: 26,2223 37717 RELINUS CAF PRIO26 # RESTORE ORIGINAL PRIORITY
020360,000179: 26,2224 05146 TC PRIOCHNG
020361,000180:
020362,000181: 26,2225 34747 CAF TRACKBIT # DON'T CONTINUE R60 UNLESS TRACKFLAG ON.
020363,000182: 26,2226 70075 MASK FLAGWRD1
020364,000183: 26,2227 10000 CCS A
020365,000184: 26,2230 12243 TCF RER60
020366,000185:
020367,000186: 26,2231 34745 CAF RNDVZBIT # IS IT P20?
020368,000187: 26,2232 70074 MASK FLAGWRD0
020369,000188: 26,2233 10000 CCS A
020370,000189: 26,2234 02240 TC +4 # YES
020371,000190: 26,2235 05353 TC PHASCHNG # NO, MUST BE P25, SET 2.11 SPOT
020372,000191: 26,2236 40112 OCT 40112
020373,000192:
020374,000193: 26,2237 05155 TC ENDOFJOB
020375,000194:
020376,000195: 26,2240 05353 TC PHASCHNG # SET 2.7 SPOT FOR P20
020377,000196: 26,2241 40072 OCT 40072
020378,000197:
020379,000198: 26,2242 05155 TC ENDOFJOB
020380,000199:
020381,000200: 26,2243 05504 RER60 TC UPFLAG # SET PRIO DISPLAY FLAG AFTER RESTART
020382,000201: 26,2244 00077 ADRES PDSPFLAG
020383,000202:
020384,000203: 26,2245 01054 TC TBASE2
020385,000204:
020386,000205: 26,2246 31010 R61TEST CA MODREG # IF WE ARE IN P00 IT MUST BE V49 OR V89
020387,000206: 26,2247 00006 EXTEND
020388,000207: 26,2250 12201 BZF ENDMANU1 # THUS WE GO TO ENDEXT VIA USER
020389,000208:
020390,000209: 26,2251 30100 CA FLAGWRD4 # ARE WE IN R61 (P20 OR P25)
020391,000210: 26,2252 74740 MASK PDSPFBIT
020392,000211: 26,2253 00006 EXTEND
020393,000212: 26,2254 16001 BZF GOTOPOOH # NO
020394,000213: 26,2255 06025 TC GOTOV56 # YES
020395,000214:
020396,000215: 26,2256 20100 BIT14+7 OCT 20100 # -
020397,000216: 26,2257 00203 OCT203 OCT 203
020398,000217: 26,2260 01422 V06N18 VN 0618
020399,000218:
020400,000219: # SUBROUTINE TO CHECK FOR G+N CONTROL, AUTO STABILIZATION
020401,000220:
020402,000221: # RETURNS WITH C(A) = + IF NOT SET FOR G+N, AUTO
020403,000222: # RETURNS WITH C(A) = +0 IF SWITCHES ARE SET
020404,000223:
020405,000224: 26,2261 00006 G+N,AUTO EXTEND
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Page 480 |
020407,000226: 26,2262 00030 READ CHAN30
020408,000227: 26,2263 74742 MASK BIT10
020409,000228: 26,2264 10000 CCS A
020410,000229: 26,2265 00002 TC Q # NOT IN G+N C(A) = +
020411,000230: 26,2266 00006 ISITAUTO EXTEND # CHECK FOR AUTO MODE
020412,000231: 26,2267 00031 READ CHAN31
020413,000232: 26,2270 74736 MASK BIT14
020414,000233: 26,2271 00002 TC Q # (+) = NOT IN AUTO, (+0) = AOK
020415,000234:
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Page 481 |
020417,000236: # PROGRAM DESCRIPTION BALLANGS
020418,000237: # MOD NO. LOG SECTION R60,R62
020419,000238: # WRITTEN BY RAMA M. AIYAWAR
020420,000239:
020421,000240: # FUNCTIONAL DESCRIPTION
020422,000241:
020423,000242: # COMPUTES LM FDAI BALL DISPLAY ANGLES
020424,000243:
020425,000244: # CALLING SEQUENCE
020426,000245:
020427,000246: # TC BALLANGS
020428,000247:
020429,000248: # NORMAL EXIT MODE
020430,000249:
020431,000250: # TC BALLEXIT (SAVED Q)
020432,000251:
020433,000252: # ALARM OR EXIT MODE NIL
020434,000253:
020435,000254: # SUBROUTINES CALLED
020436,000255:
020437,000256: # CD*TR*G
020438,000257: # ARCTAN
020439,000258:
020440,000259: # INPUT
020441,000260:
020442,000261: # CPHI,CTHETA,CPSI ARE THE ANGLES CORRESPONDING TO AOG, AIG, AMG. THEY ARE
020443,000262: # SP,2S COMPLIMENT SCALED TO HALF REVOLUTION.
020444,000263:
020445,000264: # OUTPUT
020446,000265:
020447,000266: # FDAIX, FDAIY, FDAIZ ARE THE REQUIRED BALL ANGLES SCALED TO HALF REVOLUTION
020448,000267: # SP,2S COMPLIMENT.
020449,000268:
020450,000269: # THESE ANGLES WILL BE DISPLAYED AS DEGREES AND HUNDREDTHS, IN THE ORDER ROLL, PITCH, YAW, USING NOUNS 18 & 19.
020451,000270:
020452,000271: # ERASABLE INITIALIZATION REQUIRED
020453,000272:
020454,000273: # CPHI, CTHETA, CPSI EACH A SP REGISTER
020455,000274:
020456,000275: # DEBRIS
020457,000276:
020458,000277: # A,L,Q,MPAC,SINCDU,COSCDU,PUSHLIST,BALLEXIT
020459,000278:
020460,000279: # NOMENCLATURE: CPHI, CTHETA, & CPSI REPRESENT THE OUTER, INNER, & MIDDLE GIMBAL ANGLES, RESPECTIVELY; OR
020461,000280: # EQUIVALENTLY, CDUX, CDUY, & CDUZ.
020462,000281:
020463,000282: # NOTE: ARCTAN CHECKS FOR OVERFLOW AND SHOULD BE ABLE TO HANDLE ANY SINGULARITIES.
020464,000283:
020465,000284: 26,2000 SETLOC BAWLANGS
020466,000285: 26,2000 BANK
020467,000286:
020468,000287: 26,2272 COUNT* $$/BALL
020469,000288: 26,2272 04645 BALLANGS TC MAKECADR
020470,000289: 26,2273 55337 TS BALLEXIT
020471,000290: 26,2274 30321 CA CPHI
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Page 482 |
020473,000292: 26,2275 54771 TS CDUSPOT +4
020474,000293: 26,2276 30322 CA CTHETA
020475,000294: 26,2277 54765 TS CDUSPOT
020476,000295: 26,2300 30323 CA CPSI
020477,000296: 26,2301 54767 TS CDUSPOT +2
020478,000297:
020479,000298: 26,2302 06042 TC INTPRET
020480,000299: 26,2303 45001 SETPD CALL
020481,000300: 26,2304 00001 0D
020482,000301: 26,2305 47545 CD*TR*G
020483,000302:
020484,000303: 26,2306 41345 DLOAD DMP
020485,000304: 26,2307 00742 SINCDUX # SIN (OGA)
020486,000305: 26,2310 00746 COSCDUZ # COS (MGA)
020487,000306:
020488,000307: 26,2311 57552 SL1 DCOMP # SCALE
020489,000308: 26,2312 65336 ARCSIN PDDL # YAW = ARCSIN(-SXCZ) INTO 0 PD
020490,000309: 26,2313 00740 SINCDUZ
020491,000310: 26,2314 14023 STODL SINTH # (SINTH = 18D IN PD)
020492,000311: 26,2315 00746 COSCDUZ
020493,000312: 26,2316 72405 DMP SL1 # RESCALE
020494,000313: 26,2317 00750 COSCDUX
020495,000314: 26,2320 34021 STCALL COSTH # (COSTH = 16D IN PD)
020496,000315: 26,2321 26506 ARCTAN
020497,000316: 26,2322 41325 PDDL DMP # ROLL = ARCTAN(SZ/CZCX) INTO 2 PD
020498,000317: 26,2323 00740 SINCDUZ
020499,000318: 26,2324 00742 SINCDUX
020500,000319: 26,2325 41512 SL2 PUSH # SXSZ INTO 4 PD
020501,000320: 26,2326 65205 DMP PDDL # SXSZCY INTO 4 PD
020502,000321: 26,2327 00744 COSCDUY
020503,000322: 26,2330 65205 DMP PDDL # SXSZSY INTO 6 PD
020504,000323: 26,2331 00736 SINCDUY
020505,000324: 26,2332 00750 COSCDUX
020506,000325: 26,2333 72405 DMP SL1 # CXCY
020507,000326: 26,2334 00744 COSCDUY
020508,000327: 26,2335 45425 DSU STADR # PULL UP FROM 6 PD
020509,000328: 26,2336 63756 STODL COSTH # COSTH = CXCY - SXSZSY
020510,000329: 26,2337 00736 SINCDUY
020511,000330: 26,2340 72405 DMP SL1
020512,000331: 26,2341 00750 COSCDUX # CXSY
020513,000332: 26,2342 45415 DAD STADR # PULL UP FROM 4 PD
020514,000333: 26,2343 43754 STCALL SINTH # SINTH = CXSY + SXSZCY
020515,000334: 26,2344 26506 ARCTAN # RETURNS WITH D(MPAC) = PITCH
020516,000335: 26,2345 55525 PDDL VDEF # PITCH INTO 2 PD, ROLL INTO MPAC FROM 2PD
020517,000336: 26,2346 77634 RTB # VDEF MAKES V(MPAC) = ROLL, PITCH, YAW
020518,000337: 26,2347 21621 V1STO2S
020519,000338: 26,2350 02345 STORE FDAIX # MODE IS TP
020520,000339: 26,2351 77776 EXIT
020521,000340:
020522,000341: 26,2352 31337 ENDBALL CA BALLEXIT
020523,000342:
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Page 483 |
020525,000344: 26,2353 04640 TC BANKJUMP
020526,000345:
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Page 484 |
020528,000347: # PROGRAM DESCRIPTION - VECPOINT
020529,000348:
020530,000349: # THIS INTERPRETIVE SUBROUTINE MAY BE USED TO POINT A SPACECRAFT AXIS IN A DESIRED DIRECTION. THE AXIS
020531,000350: # TO BE POINTED MUST APPEAR AS A HALF UNIT DOUBLE PRECISION VECTOR IN SUCCESSIVE LOCATIONS OF ERASABLE MEMORY
020532,000351: # BEGINNING WITH THE LOCATION CALLED SCAXIS. THE COMPONENTS OF THIS VECTOR ARE GIVEN IN SPACECRAFT COORDINATES.
020533,000352: # THE DIRECTION IN WHICH THIS AXIS IS TO BE POINTED MUST APPEAR AS A HALF UNIT DOUBLE PRECISION VECTOR IN
020534,000353: # SUCCESSIVE LOCATIONS OF ERASABLE MEMORY BEGINNING WITH THE ADDRESS CALLED POINTVSM. THE COMPONENTS OF THIS
020535,000354: # VECTOR ARE GIVEN IN STABLE MEMBER COORDINATES. WITH THIS INFORMATION VECPOINT COMPUTES A SET OF THREE GIMBAL
020536,000355: # ANGLES (2S COMPLEMENT) CORESPONDING TO THE CROSS-PRODUCT ROTATION BETWEEN SCAXIS AND POINTVSM AND STORES THEM
020537,000356: # IN T(MPAC) BEFORE RETURNING TO THE CALLER.
020538,000357:
020539,000358: # THIS ROTATION, HOWEVER, MAY BRING THE S/C INTO GIMBAL LOCK. WHEN POINTING A VECTOR IN THE Y-Z PLANE,
020540,000359: # THE TRANSPONDER AXIS, OR THE AOT FOR THE LEM, THE PROGRAM WILL CORRECT THIS PROBLEM BY ROTATING THE CROSS-
020541,000360: # PRODUCT ATTITUDE ABOUT POINTVSM BY A FIXED AMOUNT SUFFICIENT TO ROTATE THE DESIRED S/C ATTITUDE OUT OF GIMBAL
020542,000361: # 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,
020543,000362: # THE ADDITIONAL ROTATION TO AVOID GIMAL LOCK IS 35 DEGREES. IF THE AXIS IS MORE THAN 60.5 DEGEES FROM +X (OR -X)
020544,000363: # THE ADDITIONAL ROTATION IS 35 DEGREES. THE GIMBAL ANGLES CORRESPONDING TO THIS ATTITUDE ARE THEN COMPUTED AND
020545,000364: # STORED AS 2S COMPLIMENT ANGLES IN T(MPAC) BEFORE RETURNING TO THE CALLER.
020546,000365:
020547,000366: # WHEN POINTING THE X-AXIS, OR THE THRUST VECTOR, OR ANY VECTOR WITHIN 40.6 DEG OF THE X-AXIS, VECPOINT
020548,000367: # CANNOT CORRECT FOR A CROSS-PRODUCT ROTATION INTO GIMBAL LOCK. IN THIS CASE A PLATFORM REALIGNMENT WOULD BE
020549,000368: # REQUIRED TO POINT THE VECTOR IN THE DESIRED DIRECTION. AT PRESENT NO INDICATION IS GIVEN FOR THIS SITUATION
020550,000369: # EXCEPT THAT THE FINAL MIDDLE GIMBAL ANGLE IN MPAC +2 IS GREATER THAN 59 DEGREES.
020551,000370:
020552,000371: # CALLING SEQUENCE -
020553,000372:
020554,000373: # 1) LOAD SCAXIS, POINTVSM
020555,000374: # 2) CALL
020556,000375: # VECPOINT
020557,000376:
020558,000377: # RETURNS WITH
020559,000378:
020560,000379: # 1) DESIRED OUTER GIMBAL ANGLE IN MPAC
020561,000380: # 2) DESIRED INNER GIMBAL ANGLE IN MPAC +1
020562,000381: # 3) DESIRED MIDDLE GIMBAL ANGLE IN MPAC +2
020563,000382:
020564,000383: # ERASABLES USED -
020565,000384:
020566,000385: # 1) SCAXIS 6
020567,000386: # 2) POINTVSM 6
020568,000387: # 3) MIS 18
020569,000388: # 4) DEL 18
020570,000389: # 5) COF 6
020571,000390: # 6) VECQTEMP 1
020572,000391: # 7) ALL OF VAC AREA 43
020573,000392:
020574,000393: # TOTAL 99
020575,000394:
020576,000395: 27,2000 SETLOC VECPT
020577,000396: 27,2000 BANK
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Page 485 |
020579,000398: 27,2032 COUNT* $$/VECPT
020580,000399:
020581,000400: 27,2032 E6,1675 EBANK= BCDU
020582,000401:
020583,000402: 27,2032 40020 VECPNT1 STQ BOV # THIS ENTRY USES DESIRED CDUS
020584,000403: 27,2033 03324 VECQTEMP # NOT PRESENT - ENTER WITH CDUD'S IN MPAC
020585,000404: 27,2034 56035 VECPNT2
020586,000405: 27,2035 52164 VECPNT2 AXC,2 GOTO
020587,000406: 27,2036 03245 MIS
020588,000407: 27,2037 56046 STORANG
020589,000408: 27,2040 40020 VECPOINT STQ BOV # SAVE RETURN ADDRESS
020590,000409: 27,2041 03324 VECQTEMP
020591,000410: 27,2042 56043 VECLEAR # AND CLEAR OVFIND
020592,000411: 27,2043 47164 VECLEAR AXC,2 RTB
020593,000412: 27,2044 03245 MIS # READ THE PRESENT CDU ANGLES AND
020594,000413: 27,2045 44403 READCDUK # STORE THEM IN PD25, 26, 27
020595,000414: 27,2046 34032 STORANG STCALL 25D
020596,000415: 27,2047 44410 CDUTODCM # S/C AXES TO STABLE MEMBER AXES (MIS)
020597,000416: 27,2050 61375 VLOAD VXM
020598,000417: 27,2051 03773 POINTVSM # RESOLVE THE POINTING DIRECTION VF INTO
020599,000418: 27,2052 03246 MIS # INITIAL S/C AXES (VF = POINTVSM)
020600,000419: 27,2053 77656 UNIT
020601,000420: 27,2054 00035 STORE 28D
020602,000421: # PD 28 29 30 31 32 33
020603,000422: 27,2055 53435 VXV UNIT # TAKE THE CROSS PRODUCT VF X VI
020604,000423: 27,2056 03765 SCAXIS # WHERE VI = SCAXIS
020605,000424: 27,2057 57400 BOV VCOMP
020606,000425: 27,2060 56170 PICKAXIS
020607,000426: 27,2061 17270 STODL COF # CHECK MAGNITUDE
020608,000427: 27,2062 00045 36D # OF CROSS PRODUCT
020609,000428: 27,2063 50025 DSU BMN # VECTOR, IF LESS
020610,000429: 27,2064 14415 DPB-14 # THAN B-14 ASSUME
020611,000430: 27,2065 56170 PICKAXIS # UNIT OPERATION
020612,000431: 27,2066 50375 VLOAD DOT # INVALID.
020613,000432: 27,2067 03765 SCAXIS
020614,000433: 27,2070 00035 28D
020615,000434: 27,2071 65552 SL1 ARCCOS
020616,000435: 27,2072 77624 COMPMATX CALL # NOW COMPUTE THE TRANSFORMATION FROM
020617,000436: 27,2073 44527 DELCOMP # FINAL S/C AXES TO INITIAL S/C AXES MFI
020618,000437: 27,2074 75160 AXC,1 AXC,2
020619,000438: 27,2075 03245 MIS # COMPUTE THE TRANSFORMATION FROM FINAL
020620,000439: 27,2076 02230 KEL # S/C AXES TO STABLE MEMBER AXES
020621,000440: 27,2077 77624 CALL # MFS = MIS MFI
020622,000441: 27,2100 44312 MXM3 # (IN PD LIST)
020623,000442:
020624,000443: 27,2101 51545 DLOAD ABS
020625,000444: 27,2102 00007 6 # MFS6 = SIN(CPSI) $2
020626,000445: 27,2103 50025 DSU BMN
020627,000446: 27,2104 14402 SINGIMLC # = SIN(59 DEGS) $2
020628,000447: 27,2105 56160 FINDGIMB # /CPSI/ LESS THAN 59 DEGS
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Page 486 |
020630,000449: # I.E. DESIRED ATTITUDE NOT IN GIMBAL LOCK
020631,000450:
020632,000451: 27,2106 51545 DLOAD ABS # CHECK TO SEE IF WE ARE POINTING
020633,000452: 27,2107 03765 SCAXIS # THE THRUST AXIS
020634,000453: 27,2110 51025 DSU BPL
020635,000454: 27,2111 14404 SINVEC1 # SIN 49.4 DEGS $2
020636,000455: 27,2112 56160 FINDGIMB # IF SO, WE ARE TRYING TO POINT IT INTO
020637,000456: 27,2113 77775 VLOAD # GIMBAL LOCK, ABORT COULD GO HERE
020638,000457: 27,2114 77626 STADR
020639,000458: 27,2115 50515 STOVL MIS +12D
020640,000459: 27,2116 77626 STADR # STORE MFS (IN PD LIST) IN MIS
020641,000460: 27,2117 50523 STOVL MIS +6
020642,000461: 27,2120 77626 STADR
020643,000462: 27,2121 50531 STOVL MIS
020644,000463: 27,2122 03254 MIS +6 # INNER GIMBAL AXIS IN FINAL S/C AXES
020645,000464: 27,2123 57444 BPL VCOMP # LOCATE THE IG AXIS DIRECTION CLOSEST TO
020646,000465: 27,2124 56125 IGSAMEX # FINAL X S/C AXIS
020647,000466:
020648,000467: 27,2125 50035 IGSAMEX VXV BMN # FIND THE SHORTEST WAY OF ROTATING THE
020649,000468: 27,2126 03765 SCAXIS # S/C OUT OF GIMBAL LOCK BY A ROTATION
020650,000469: 27,2127 56134 U=SCAXIS # ABOUT +- SCAXIS, I.E. IF (IG (SGN MFS3)
020651,000470: # X SCAXIS . XF) LESS THAN 0, U = SCAXIS
020652,000471: # OTHERWISE U = -SCAXIS
020653,000472:
020654,000473: 27,2130 57575 VLOAD VCOMP
020655,000474: 27,2131 03765 SCAXIS
020656,000475: 27,2132 37270 STCALL COF # ROTATE ABOUT -SCAXIS
020657,000476: 27,2133 56137 CHEKAXIS
020658,000477: 27,2134 77775 U=SCAXIS VLOAD
020659,000478: 27,2135 03765 SCAXIS
020660,000479: 27,2136 03270 STORE COF # ROTATE ABOUT + SCAXIS
020661,000480: 27,2137 51545 CHEKAXIS DLOAD ABS
020662,000481: 27,2140 03765 SCAXIS # SEE IF WE ARE POINTING THE AOT
020663,000482: 27,2141 51025 DSU BPL
020664,000483: 27,2142 14406 SINVEC2 # SIN 29.5 DEGS $2
020665,000484: 27,2143 56147 PICKANG1 # IF SO, ROTATE 50 DEGS ABOUT +- SCAXIS
020666,000485: 27,2144 52145 DLOAD GOTO # IF NOT, MUST BE POINTING THE TRANSPONDER
020667,000486: 27,2145 14412 VECANG2 # OR SOME VECTOR IN THE Y, OR Z PLANE
020668,000487: 27,2146 56151 COMPMFSN # IN THIS CASE ROTATE 35 DEGS TO GET OUT
020669,000488: # OF GIMBAL LOCK (VECANG2 $360)
020670,000489: 27,2147 77745 PICKANG1 DLOAD
020671,000490: 27,2150 14410 VECANG1 # = 50 DEGS $ 360
020672,000491: 27,2151 77624 COMPMFSN CALL
020673,000492: 27,2152 44527 DELCOMP # COMPUTE THE ROTATION ABOUT SCAXIS TO
020674,000493: 27,2153 75160 AXC,1 AXC,2 # BRING MFS OUT OF GIMBAL LOCK
020675,000494: 27,2154 03245 MIS
020676,000495: 27,2155 02230 KEL
020677,000496: 27,2156 77624 CALL # COMPUTE THE NEW TRANSFORMATION FROM
020678,000497: 27,2157 44312 MXM3 # DESIRED S/C AXES TO STABLE MEMBER AXES
020679,000498: # WHICH WILL ALIGN VI WITH VF AND AVOID
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020681,000500: # GIMBAL LOCK
020682,000501: 27,2160 45160 FINDGIMB AXC,1 CALL
020683,000502: 27,2161 00000 0 # EXTRACT THE COMMANDED CDU ANGLES FROM
020684,000503: 27,2162 44654 DCMTOCDU # THIS MATRIX
020685,000504: 27,2163 40234 RTB SETPD
020686,000505: 27,2164 21621 V1STO2S # CONVERT TO 2:S COMPLEMENT
020687,000506: 27,2165 00001 0
020688,000507: 27,2166 77650 GOTO
020689,000508: 27,2167 03324 VECQTEMP # RETURN TO CALLER
020690,000509:
020691,000510: 27,2170 50375 PICKAXIS VLOAD DOT # IF VF X VI = 0, FIND VF . VI
020692,000511: 27,2171 00035 28D
020693,000512: 27,2172 03765 SCAXIS
020694,000513: 27,2173 72240 BMN TLOAD
020695,000514: 27,2174 54354 ROT180
020696,000515: 27,2175 00032 25D
020697,000516: 27,2176 77650 GOTO # IF VF = VI, CDU DESIRED = PRESENT CDU
020698,000517: 27,2177 03324 VECQTEMP # PRESENT CDU ANGLES
020699,000518:
020700,000519: 35,2000 BANK 35
020701,000520: 26,2000 SETLOC MANUVER1
020702,000521: 26,2000 BANK
020703,000522: 26,2354 47375 ROT180 VLOAD VXV # IF VF, VI ANTIPARALLEL, 108 DEG ROTATION
020704,000523: 26,2355 03254 MIS +6 # IS REQUIRED. Y STABLE MEMBER AXIS IN
020705,000524: 26,2356 06522 HIDPHALF # INITIAL S/C AXES.
020706,000525: 26,2357 47256 UNIT VXV # FIND Y(SM) X X(I)
020707,000526: 26,2360 03765 SCAXIS # FIND UNIT(VI X UNIT(Y(SM) X X(I)))
020708,000527: 26,2361 40056 UNIT BOV # I.E. PICK A VECTOR IN THE PLANE OF X(I),
020709,000528: 26,2362 54376 PICKX # Y(SM) PERPENDICULAR TO VI
020710,000529: 26,2363 17270 STODL COF
020711,000530: 26,2364 00045 36D # CHECK MAGNITUDE
020712,000531: 26,2365 50025 DSU BMN # OF THIS VECTOR.
020713,000532: 26,2366 14415 DPB-14 # IF LESS THAN B-14,
020714,000533: 26,2367 54376 PICKX # PICK X-AXIS.
020715,000534: 26,2370 77775 VLOAD
020716,000535: 26,2371 03270 COF
020717,000536: 26,2372 17270 XROT STODL COF
020718,000537: 26,2373 06522 HIDPHALF
020719,000538: 26,2374 77650 GOTO
020720,000539: 26,2375 56072 COMPMATX
020721,000540: 26,2376 52175 PICKX VLOAD GOTO # PICK THE XAXIS IN THIS CASE
020722,000541: 26,2377 06522 HIDPHALF
020723,000542: 26,2400 54372 XROT
020724,000543: 26,2401 15555 35172 SINGIMLC 2DEC .4285836003 # = SIN(59) $2
020725,000544: 26,2403 14113 36326 SINVEC1 2DEC .3796356537 # = SIN(49.4) $2
020726,000545: 26,2405 07701 35703 SINVEC2 2DEC .2462117800 # = SIN(29.5) $2
020727,000546: 26,2407 04343 21616 VECANG1 2DEC .1388888889 # = 50 DEGREES $360
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020729,000548: 26,2411 03070 34344 VECANG2 2DEC .09722222222 # = 35 DEGREES $360
020730,000549:
020731,000550: 26,2413 00000 1BITDP OCT 0 # KEEP THIS BEFORE DPB(-14) *********
020732,000551: 26,2414 00001 DPB-14 OCT 00001
020733,000552: 26,2415 00000 OCT 00000
020734,000553:
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Page 489 |
020736,000555: # ROUTINE FOR INITIATING AUTOMATIC MANEUVER VIA KEYBOARD (V49)
020737,000556:
020738,000557: 34,2000 BANK 34
020739,000558: 23,2000 SETLOC R62
020740,000559: 23,2000 BANK
020741,000560: 23,2103 E6,1675 EBANK= BCDU
020742,000561:
020743,000562: 23,2103 COUNT* $$/R62
020744,000563:
020745,000564: 23,2103 23,2103 R62DISP EQUALS R62FLASH
020746,000565:
020747,000566: 23,2103 35010 R62FLASH CAF V06N22 # FLASH V06N22 AND
020748,000567: 23,2104 04616 TC BANKCALL # ICDU ANGLES
020749,000568: 23,2105 20477 CADR GOFLASH
020750,000569: 23,2106 15472 TCF ENDEXT # TERMINATE
020751,000570: 23,2107 12111 TCF GOMOVE # PROCEED
020752,000571: 23,2110 12103 TCF R62FLASH # ENTER
020753,000572:
020754,000573: # ASTRONAUT MAY LOAD NEW ICDUS AT THIS
020755,000574: # POINT
020756,000575: 23,2111 05504 GOMOVE TC UPFLAG # SET FOR 3-AXIS MANEUVER
020757,000576: 23,2112 00124 ADRES 3AXISFLG
020758,000577:
020759,000578: 23,2113 04616 TC BANKCALL
020760,000579: 23,2114 54123 CADR R60LEM
020761,000580: 23,2115 15472 TCF ENDEXT # END R62
020762,000581:
End of include-file R60,R62.agc. Parent file is MAIN.agc