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. |
020196,000002: ## Copyright: Public domain.
020197,000003: ## Filename: R60_62.agc
020198,000004: ## Purpose: A section of Luminary 1C, revision 131.
020199,000005: ## It is part of the source code for the Lunar Module's (LM)
020200,000006: ## Apollo Guidance Computer (AGC) for Apollo 13.
020201,000007: ## This file is intended to be a faithful transcription, except
020202,000008: ## that the code format has been changed to conform to the
020203,000009: ## requirements of the yaYUL assembler rather than the
020204,000010: ## original YUL assembler.
020205,000011: ## Reference: pp. 476-489
020206,000012: ## Contact: Ron Burkey <info@sandroid.org>.
020207,000013: ## Website: www.ibiblio.org/apollo/index.html
020208,000014: ## Mod history: 05/14/03 RSB. Began transcribing.
020209,000015: ## 05/14/05 RSB Corrected website reference above.
020210,000016: ## 2017-01-06 RSB Page numbers now agree with those on the
020211,000017: ## original harcopy, as opposed to the PDF page
020212,000018: ## numbers in 1701.pdf.
020213,000019: ## 2017-01-27 RSB Back-ported a comment-text fix identified in Luminary 69.
020214,000020: ## 2017-02-23 RSB Proofed comment text using octopus/ProoferComments.
020215,000021: ## 2017-02-28 RSB Fixed lingering typos.
020216,000022: ## 2017-03-09 RSB Comment text fixes noted in proofing Luminary 116.
020217,000023:
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Page 476 |
020219,000025: # MOD NO: 0 DATE: 1 MAY 1968
020220,000026: # MOD BY: DIGITAL DEVEL GROUP LOG SECTION R60,R62
020221,000027:
020222,000028: # FUNCTIONAL DESCRIPTION:
020223,000029:
020224,000030: # CALLED AS A GENERAL SUBROUTINE TO MANEUVER THE LM TO A SPECIFIED
020225,000031: # ATTITUDE.
020226,000032:
020227,000033: # 1. IF THE 3-AXIS FLAG IS NOT SET THE FINAL CDU ANGLES ARE
020228,000034: # CALCULATED (VECPOINT).
020229,000035:
020230,000036: # 2. THE FDAI BALL ANGLES (NOUN 18) ARE CALCULATED (BALLANGS).
020231,000037:
020232,000038: # 3. REQUEST FLASHING DISPLAY V50 N18 PLEASE PERFORM AUTO MANEUVER.
020233,000039:
020234,000040: # 4. IF PRIORITY DISPLAY FLAG IS SET DO A PHASECHANGE. THEN AWAIT
020235,000041: # ASTRONAUT RESPONSE.
020236,000042:
020237,000043: # 5. DISPLAY RESPONSE RETURNS:
020238,000044:
020239,000045: # A. ENTER - RESET 3-AXIS FLAG AND RETURN TO CLIENT.
020240,000046:
020241,000047: # B. TERMINATE - IF IN P00 GO TO STEP 5A. OTHERWISE CHECK IF R61 IS
020242,000048: # THE CALLING PROGRAM. IF IN R61 AN EXIT IS MADE TO GOTOV56. IF
020243,000049: # NOT IN R61 AN EXIT IS DONE VIA GOTOP00H.
020244,000050:
020245,000051: # C. PROCEED - CONTINUE WITH PROGRAM AT STEP 6.
020246,000052:
020247,000053: # 6. IF THE 3-AXIS FLAG IS NOT SET, THE FINAL CDU ANGLES ARE CALCULATED
020248,000054: # (VECPOINT).
020249,000055:
020250,000056: # 7. THE FDAI BALL ANGLES (NOUN 18) ARE CALCULATED (BALLANGS).
020251,000057:
020252,000058: # 8. IF THE G+N SWITCH IS NOT SET GO BACK TO STEP 3.
020253,000059: #
020254,000060: # 9. IF THE AUTO SWITCH IS NOT SET GO BACK TO STEP 3.
020255,000061:
020256,000062: # 10. NONFLASHING DISPLAY V06N18 (FDAI ANGLES).
020257,000063:
020258,000064: # 11. DO A PHASECHANGE.
020259,000065:
020260,000066: # 12. DO A MANEUVER CALCULATION AND ICDU DRIVE ROUTINE TO ACHIEVE FINAL
020261,000067: # GIMBAL ANGLES (GOMANUR).
020262,000068:
020263,000069: # 13. AT END OF MANEUVER GO TO STEP 3.
020264,000070:
020265,000071: # IF SATISFACTORY MANEUVER STEP 5A EXITS R60.
020266,000072: # FOR FURTHER ADJUSTMENT OF THE VEHICLE ATTITUDE ABOUT THE
020267,000073: # DESIRED VECTOR, THE ROUTINE MAY BE PERFORMED AGAIN STARTING AT
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Page 477 |
020269,000075: # STEP 5C.
020270,000076:
020271,000077: # CALLING SEQUENCE: TC BANKCALL
020272,000078: # CADR R60LEM
020273,000079:
020274,000080: # ERASABLE INITIALIZATION REQUIRED: SCAXIS, POINTVSM (FOR VECPOINT)
020275,000081: # 3AXISFLG.
020276,000082:
020277,000083: # SUBROUTINES CALLED: VECPOINT, BALLANGS, GOPERF2R, LINUS, GODSPER,
020278,000084: # GOMANUR, DOWNFLAG, PHASCHNG, UPFLAG
020279,000085:
020280,000086: # NORMAL EXIT MODES: CAE TEMPR60 (CALLERS RETURN ADDRESS)
020281,000087: # TC BANKJUMP
020282,000088:
020283,000089: # ALARMS: NONE
020284,000090:
020285,000091: # OUTPUT: NONE
020286,000092:
020287,000093: # DEBRIS: CPHI, CTHETA, CPSI, 3AXISFLG, TBASE2
020288,000094:
020289,000095: 34,2000 BANK 34
020290,000096: 26,2000 SETLOC MANUVER
020291,000097: 26,2000 BANK
020292,000098:
020293,000099: 26,2123 1163 EBANK= TEMPR60
020294,000100:
020295,000101: 26,2123 COUNT* $$/R06
020296,000102: 26,2123 04645 R60LEM TC MAKECADR
020297,000103: 26,2124 55163 TS TEMPR60
020298,000104:
020299,000105: 26,2125 34746 REDOMANN CAF 3AXISBIT
020300,000106: 26,2126 70101 MASK FLAGWRD5 # IS 3-AXIS FLAG SET
020301,000107: 26,2127 10000 CCS A
020302,000108: 26,2130 12136 TCF TOBALL # YES
020303,000109: 26,2131 06042 TC INTPRET
020304,000110: 26,2132 77624 CALL
020305,000111: 26,2133 56040 VECPOINT # TO COMPUTE FINAL ANGLES
020306,000112: 26,2134 00322 STORE CPHI # STORE FINAL ANGLES - CPHI, CTHETA, CPSI
020307,000113: 26,2135 77776 EXIT
020308,000114:
020309,000115: 26,2136 05504 TOBALL TC UPFLAG # INSURE THAT TOTAL ATTITUDE ERRORS ARE
020310,000116: 26,2137 00013 ADRES NEEDLFLG # DISPLAYED ON FDAI ERROR NEEDLES
020311,000117: 26,2140 05516 TC DOWNFLAG
020312,000118: 26,2141 00000 ADRES NEED2FLG
020313,000119: 26,2142 04616 TC BANKCALL
020314,000120: 26,2143 54272 CADR BALLANGS # TO CONVERT ANGLES TO FDAI
020315,000121: 26,2144 32260 TOBALLA CAF V06N18
020316,000122: 26,2145 04616 TC BANKCALL
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Page 478 |
020318,000124: 26,2146 20711 CADR GOPERF2R # DISPLAY PLEASE PERFORM AUTO MANEUVER
020319,000125: 26,2147 02246 TC R61TEST
020320,000126: 26,2150 02154 TC REDOMANC # PROCEED
020321,000127: 26,2151 02201 TC ENDMANU1 # ENTER I.E. FINISHED WITH R60
020322,000128: 26,2152 02205 TC CHKLINUS # TO CHECK FOR PRIORITY DISPLAYS
020323,000129: 26,2153 05155 TC ENDOFJOB
020324,000130:
020325,000131: 26,2154 34746 REDOMANC CAF 3AXISBIT
020326,000132: 26,2155 70101 MASK FLAGWRD5 # IS 3-AXIS FLAG SET
020327,000133: 26,2156 10000 CCS A
020328,000134: 26,2157 12165 TCF TOBALLC # YES
020329,000135: 26,2160 06042 TC INTPRET
020330,000136: 26,2161 77624 CALL
020331,000137: 26,2162 56040 VECPOINT # TO COMPUTE FINAL ANGLES
020332,000138: 26,2163 00322 STORE CPHI # STORE ANGLES
020333,000139: 26,2164 77776 EXIT
020334,000140:
020335,000141: 26,2165 04616 TOBALLC TC BANKCALL
020336,000142: 26,2166 54272 CADR BALLANGS # TO CONVERT ANGLES TO FDAI
020337,000143: 26,2167 02261 TC G+N,AUTO # CHECK AUTO MODE
020338,000144: 26,2170 10000 CCS A
020339,000145: 26,2171 12144 TCF TOBALLA # NOT AUTO, GO REREQUEST AUTO MANEUVER.
020340,000146:
020341,000147: 26,2172 32260 AUTOMANV CAF V06N18 # STATIC DISPLAY DURING AUTO MANEUVER
020342,000148: 26,2173 04616 TC BANKCALL # -
020343,000149: 26,2174 20452 CADR GODSPR # -
020344,000150: 26,2175 02205 TC CHKLINUS # TO CHECK FOR PRIORITY DISPLAYS
020345,000151:
020346,000152: 26,2176 04616 STARTMNV TC BANKCALL # PERFORM MANEUVER VIA KALCMANU
020347,000153: 26,2177 17741 CADR GOMANUR
020348,000154:
020349,000155: 26,2200 12144 ENDMANUV TCF TOBALLA # FINISHED MANEUVER.
020350,000156: 26,2201 05516 ENDMANU1 TC DOWNFLAG # RESET 3-AXIS FLAG
020351,000157: 26,2202 00124 ADRES 3AXISFLG
020352,000158: 26,2203 31163 CAE TEMPR60 # -
020353,000159: 26,2204 04640 TC BANKJUMP # -
020354,000160:
020355,000161: 26,2205 40100 CHKLINUS CS FLAGWRD4
020356,000162: 26,2206 74740 MASK PDSPFBIT # IS PRIORITY DISPLAY FLAG SET?
020357,000163: 26,2207 10000 CCS A # -
020358,000164: 26,2210 00002 TC Q # NO - EXIT
020359,000165: 26,2211 30002 CA Q
020360,000166: 26,2212 54156 TS MPAC +2 # SAVE RETURN
020361,000167: 26,2213 46250 CS THREE # OBTAIN LOCATION FOR RESTART
020362,000168: 26,2214 60133 AD BUF2 # HOLDS Q OF LAST DISPLAY
020363,000169: 26,2215 55054 TS TBASE2
020364,000170:
020365,000171: 26,2216 05353 TC PHASCHNG
020366,000172: 26,2217 00132 OCT 00132
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Page 479 |
020368,000174: 26,2220 34745 CAF BIT7
020369,000175: 26,2221 05464 TC LINUS # GO SET BITS FOR PRIORITY DISPLAY -
020370,000176: 26,2222 00156 TC MPAC +2
020371,000177:
020372,000178: 26,2223 37717 RELINUS CAF PRIO26 # RESTORE ORIGINAL PRIORITY
020373,000179: 26,2224 05146 TC PRIOCHNG
020374,000180:
020375,000181: 26,2225 34747 CAF TRACKBIT # DON'T CONTINUE R60 UNLESS TRACKFLAG ON.
020376,000182: 26,2226 70075 MASK FLAGWRD1
020377,000183: 26,2227 10000 CCS A
020378,000184: 26,2230 12243 TCF RER60
020379,000185:
020380,000186: 26,2231 34745 CAF RNDVZBIT # IS IT P20?
020381,000187: 26,2232 70074 MASK FLAGWRD0
020382,000188: 26,2233 10000 CCS A
020383,000189: 26,2234 02240 TC +4 # YES
020384,000190: 26,2235 05353 TC PHASCHNG # NO, MUST BE P25, SET 2.11 SPOT
020385,000191: 26,2236 40112 OCT 40112
020386,000192:
020387,000193: 26,2237 05155 TC ENDOFJOB
020388,000194:
020389,000195: 26,2240 05353 TC PHASCHNG # SET 2.7 SPOT FOR P20
020390,000196: 26,2241 40072 OCT 40072
020391,000197:
020392,000198: 26,2242 05155 TC ENDOFJOB
020393,000199:
020394,000200: 26,2243 05504 RER60 TC UPFLAG # SET PRIO DISPLAY FLAG AFTER RESTART
020395,000201: 26,2244 00077 ADRES PDSPFLAG
020396,000202:
020397,000203: 26,2245 01054 TC TBASE2
020398,000204:
020399,000205: 26,2246 31010 R61TEST CA MODREG # IF WE ARE IN P00 IT MUST BE V49 OR V89
020400,000206: 26,2247 00006 EXTEND
020401,000207: 26,2250 12201 BZF ENDMANU1 # THUS WE GO TO ENDEXT VIA USER
020402,000208:
020403,000209: 26,2251 30100 CA FLAGWRD4 # ARE WE IN R61 (P20 OR P25)
020404,000210: 26,2252 74740 MASK PDSPFBIT
020405,000211: 26,2253 00006 EXTEND
020406,000212: 26,2254 16001 BZF GOTOPOOH # NO
020407,000213: 26,2255 06025 TC GOTOV56 # YES
020408,000214:
020409,000215: 26,2256 20100 BIT14+7 OCT 20100 # -
020410,000216: 26,2257 00203 OCT203 OCT 203
020411,000217: 26,2260 01422 V06N18 VN 0618
020412,000218:
020413,000219: # SUBROUTINE TO CHECK FOR G+N CONTROL, AUTO STABILIZATION
020414,000220:
020415,000221: # RETURNS WITH C(A) = + IF NOT SET FOR G+N, AUTO
020416,000222: # RETURNS WITH C(A) = +0 IF SWITCHES ARE SET
020417,000223:
020418,000224: 26,2261 00006 G+N,AUTO EXTEND
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Page 480 |
020420,000226: 26,2262 00030 READ CHAN30
020421,000227: 26,2263 74742 MASK BIT10
020422,000228: 26,2264 10000 CCS A
020423,000229: 26,2265 00002 TC Q # NOT IN G+N C(A) = +
020424,000230: 26,2266 00006 ISITAUTO EXTEND # CHECK FOR AUTO MODE
020425,000231: 26,2267 00031 READ CHAN31
020426,000232: 26,2270 74736 MASK BIT14
020427,000233: 26,2271 00002 TC Q # (+) = NOT IN AUTO, (+0) = AOK
020428,000234:
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Page 481 |
020430,000236: # PROGRAM DESCRIPTION BALLANGS
020431,000237: # MOD NO. LOG SECTION R60,R62
020432,000238: # WRITTEN BY RAMA M. AIYAWAR
020433,000239:
020434,000240: # FUNCTIONAL DESCRIPTION
020435,000241:
020436,000242: # COMPUTES LM FDAI BALL DISPLAY ANGLES
020437,000243:
020438,000244: # CALLING SEQUENCE
020439,000245:
020440,000246: # TC BALLANGS
020441,000247:
020442,000248: # NORMAL EXIT MODE
020443,000249:
020444,000250: # TC BALLEXIT (SAVED Q)
020445,000251:
020446,000252: # ALARM OR EXIT MODE NIL
020447,000253:
020448,000254: # SUBROUTINES CALLED
020449,000255:
020450,000256: # CD*TR*G
020451,000257: # ARCTAN
020452,000258:
020453,000259: # INPUT
020454,000260:
020455,000261: # CPHI,CTHETA,CPSI ARE THE ANGLES CORRESPONDING TO AOG, AIG, AMG. THEY ARE
020456,000262: # SP,2S COMPLIMENT SCALED TO HALF REVOLUTION.
020457,000263:
020458,000264: # OUTPUT
020459,000265:
020460,000266: # FDAIX, FDAIY, FDAIZ ARE THE REQUIRED BALL ANGLES SCALED TO HALF REVOLUTION
020461,000267: # SP,2S COMPLIMENT.
020462,000268:
020463,000269: # THESE ANGLES WILL BE DISPLAYED AS DEGREES AND HUNDREDTHS, IN THE ORDER ROLL, PITCH, YAW, USING NOUNS 18 & 19.
020464,000270:
020465,000271: # ERASABLE INITIALIZATION REQUIRED
020466,000272:
020467,000273: # CPHI, CTHETA, CPSI EACH A SP REGISTER
020468,000274:
020469,000275: # DEBRIS
020470,000276:
020471,000277: # A,L,Q,MPAC,SINCDU,COSCDU,PUSHLIST,BALLEXIT
020472,000278:
020473,000279: # NOMENCLATURE: CPHI, CTHETA, & CPSI REPRESENT THE OUTER, INNER, & MIDDLE GIMBAL ANGLES, RESPECTIVELY; OR
020474,000280: # EQUIVALENTLY, CDUX, CDUY, & CDUZ.
020475,000281:
020476,000282: # NOTE: ARCTAN CHECKS FOR OVERFLOW AND SHOULD BE ABLE TO HANDLE ANY SINGULARITIES.
020477,000283:
020478,000284: 26,2000 SETLOC BAWLANGS
020479,000285: 26,2000 BANK
020480,000286:
020481,000287: 26,2272 COUNT* $$/BALL
020482,000288: 26,2272 04645 BALLANGS TC MAKECADR
020483,000289: 26,2273 55337 TS BALLEXIT
020484,000290: 26,2274 30321 CA CPHI
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Page 482 |
020486,000292: 26,2275 54771 TS CDUSPOT +4
020487,000293: 26,2276 30322 CA CTHETA
020488,000294: 26,2277 54765 TS CDUSPOT
020489,000295: 26,2300 30323 CA CPSI
020490,000296: 26,2301 54767 TS CDUSPOT +2
020491,000297:
020492,000298: 26,2302 06042 TC INTPRET
020493,000299: 26,2303 45001 SETPD CALL
020494,000300: 26,2304 00001 0D
020495,000301: 26,2305 47545 CD*TR*G
020496,000302:
020497,000303: 26,2306 41345 DLOAD DMP
020498,000304: 26,2307 00742 SINCDUX # SIN (OGA)
020499,000305: 26,2310 00746 COSCDUZ # COS (MGA)
020500,000306:
020501,000307: 26,2311 57552 SL1 DCOMP # SCALE
020502,000308: 26,2312 65336 ARCSIN PDDL # YAW = ARCSIN(-SXCZ) INTO 0 PD
020503,000309: 26,2313 00740 SINCDUZ
020504,000310: 26,2314 14023 STODL SINTH # (SINTH = 18D IN PD)
020505,000311: 26,2315 00746 COSCDUZ
020506,000312: 26,2316 72405 DMP SL1 # RESCALE
020507,000313: 26,2317 00750 COSCDUX
020508,000314: 26,2320 34021 STCALL COSTH # (COSTH = 16D IN PD)
020509,000315: 26,2321 26506 ARCTAN
020510,000316: 26,2322 41325 PDDL DMP # ROLL = ARCTAN(SZ/CZCX) INTO 2 PD
020511,000317: 26,2323 00740 SINCDUZ
020512,000318: 26,2324 00742 SINCDUX
020513,000319: 26,2325 41512 SL2 PUSH # SXSZ INTO 4 PD
020514,000320: 26,2326 65205 DMP PDDL # SXSZCY INTO 4 PD
020515,000321: 26,2327 00744 COSCDUY
020516,000322: 26,2330 65205 DMP PDDL # SXSZSY INTO 6 PD
020517,000323: 26,2331 00736 SINCDUY
020518,000324: 26,2332 00750 COSCDUX
020519,000325: 26,2333 72405 DMP SL1 # CXCY
020520,000326: 26,2334 00744 COSCDUY
020521,000327: 26,2335 45425 DSU STADR # PULL UP FROM 6 PD
020522,000328: 26,2336 63756 STODL COSTH # COSTH = CXCY - SXSZSY
020523,000329: 26,2337 00736 SINCDUY
020524,000330: 26,2340 72405 DMP SL1
020525,000331: 26,2341 00750 COSCDUX # CXSY
020526,000332: 26,2342 45415 DAD STADR # PULL UP FROM 4 PD
020527,000333: 26,2343 43754 STCALL SINTH # SINTH = CXSY + SXSZCY
020528,000334: 26,2344 26506 ARCTAN # RETURNS WITH D(MPAC) = PITCH
020529,000335: 26,2345 55525 PDDL VDEF # PITCH INTO 2 PD, ROLL INTO MPAC FROM 2PD
020530,000336: 26,2346 77634 RTB # VDEF MAKES V(MPAC) = ROLL, PITCH, YAW
020531,000337: 26,2347 21621 V1STO2S
020532,000338: 26,2350 02345 STORE FDAIX # MODE IS TP
020533,000339: 26,2351 77776 EXIT
020534,000340:
020535,000341: 26,2352 31337 ENDBALL CA BALLEXIT
020536,000342:
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Page 483 |
020538,000344: 26,2353 04640 TC BANKJUMP
020539,000345:
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Page 484 |
020541,000347: # PROGRAM DESCRIPTION - VECPOINT
020542,000348:
020543,000349: # THIS INTERPRETIVE SUBROUTINE MAY BE USED TO POINT A SPACECRAFT AXIS IN A DESIRED DIRECTION. THE AXIS
020544,000350: # TO BE POINTED MUST APPEAR AS A HALF UNIT DOUBLE PRECISION VECTOR IN SUCCESSIVE LOCATIONS OF ERASABLE MEMORY
020545,000351: # BEGINNING WITH THE LOCATION CALLED SCAXIS. THE COMPONENTS OF THIS VECTOR ARE GIVEN IN SPACECRAFT COORDINATES.
020546,000352: # THE DIRECTION IN WHICH THIS AXIS IS TO BE POINTED MUST APPEAR AS A HALF UNIT DOUBLE PRECISION VECTOR IN
020547,000353: # SUCCESSIVE LOCATIONS OF ERASABLE MEMORY BEGINNING WITH THE ADDRESS CALLED POINTVSM. THE COMPONENTS OF THIS
020548,000354: # VECTOR ARE GIVEN IN STABLE MEMBER COORDINATES. WITH THIS INFORMATION VECPOINT COMPUTES A SET OF THREE GIMBAL
020549,000355: # ANGLES (2S COMPLEMENT) CORESPONDING TO THE CROSS-PRODUCT ROTATION BETWEEN SCAXIS AND POINTVSM AND STORES THEM
020550,000356: # IN T(MPAC) BEFORE RETURNING TO THE CALLER.
020551,000357:
020552,000358: # THIS ROTATION, HOWEVER, MAY BRING THE S/C INTO GIMBAL LOCK. WHEN POINTING A VECTOR IN THE Y-Z PLANE,
020553,000359: # THE TRANSPONDER AXIS, OR THE AOT FOR THE LEM, THE PROGRAM WILL CORRECT THIS PROBLEM BY ROTATING THE CROSS-
020554,000360: # PRODUCT ATTITUDE ABOUT POINTVSM BY A FIXED AMOUNT SUFFICIENT TO ROTATE THE DESIRED S/C ATTITUDE OUT OF GIMBAL
020555,000361: # 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,
020556,000362: # THE ADDITIONAL ROTATION TO AVOID GIMAL LOCK IS 35 DEGREES. IF THE AXIS IS MORE THAN 60.5 DEGEES FROM +X (OR -X)
020557,000363: # THE ADDITIONAL ROTATION IS 35 DEGREES. THE GIMBAL ANGLES CORRESPONDING TO THIS ATTITUDE ARE THEN COMPUTED AND
020558,000364: # STORED AS 2S COMPLIMENT ANGLES IN T(MPAC) BEFORE RETURNING TO THE CALLER.
020559,000365:
020560,000366: # WHEN POINTING THE X-AXIS, OR THE THRUST VECTOR, OR ANY VECTOR WITHIN 40.6 DEG OF THE X-AXIS, VECPOINT
020561,000367: # CANNOT CORRECT FOR A CROSS-PRODUCT ROTATION INTO GIMBAL LOCK. IN THIS CASE A PLATFORM REALIGNMENT WOULD BE
020562,000368: # REQUIRED TO POINT THE VECTOR IN THE DESIRED DIRECTION. AT PRESENT NO INDICATION IS GIVEN FOR THIS SITUATION
020563,000369: # EXCEPT THAT THE FINAL MIDDLE GIMBAL ANGLE IN MPAC +2 IS GREATER THAN 59 DEGREES.
020564,000370:
020565,000371: # CALLING SEQUENCE -
020566,000372:
020567,000373: # 1) LOAD SCAXIS, POINTVSM
020568,000374: # 2) CALL
020569,000375: # VECPOINT
020570,000376:
020571,000377: # RETURNS WITH
020572,000378:
020573,000379: # 1) DESIRED OUTER GIMBAL ANGLE IN MPAC
020574,000380: # 2) DESIRED INNER GIMBAL ANGLE IN MPAC +1
020575,000381: # 3) DESIRED MIDDLE GIMBAL ANGLE IN MPAC +2
020576,000382:
020577,000383: # ERASABLES USED -
020578,000384:
020579,000385: # 1) SCAXIS 6
020580,000386: # 2) POINTVSM 6
020581,000387: # 3) MIS 18
020582,000388: # 4) DEL 18
020583,000389: # 5) COF 6
020584,000390: # 6) VECQTEMP 1
020585,000391: # 7) ALL OF VAC AREA 43
020586,000392:
020587,000393: # TOTAL 99
020588,000394:
020589,000395: 27,2000 SETLOC VECPT
020590,000396: 27,2000 BANK
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Page 485 |
020592,000398: 27,2032 COUNT* $$/VECPT
020593,000399:
020594,000400: 27,2032 E6,1675 EBANK= BCDU
020595,000401:
020596,000402: 27,2032 40020 VECPNT1 STQ BOV # THIS ENTRY USES DESIRED CDUS
020597,000403: 27,2033 03324 VECQTEMP # NOT PRESENT - ENTER WITH CDUD'S IN MPAC
020598,000404: 27,2034 56035 VECPNT2
020599,000405: 27,2035 52164 VECPNT2 AXC,2 GOTO
020600,000406: 27,2036 03245 MIS
020601,000407: 27,2037 56046 STORANG
020602,000408: 27,2040 40020 VECPOINT STQ BOV # SAVE RETURN ADDRESS
020603,000409: 27,2041 03324 VECQTEMP
020604,000410: 27,2042 56043 VECLEAR # AND CLEAR OVFIND
020605,000411: 27,2043 47164 VECLEAR AXC,2 RTB
020606,000412: 27,2044 03245 MIS # READ THE PRESENT CDU ANGLES AND
020607,000413: 27,2045 44403 READCDUK # STORE THEM IN PD25, 26, 27
020608,000414: 27,2046 34032 STORANG STCALL 25D
020609,000415: 27,2047 44410 CDUTODCM # S/C AXES TO STABLE MEMBER AXES (MIS)
020610,000416: 27,2050 61375 VLOAD VXM
020611,000417: 27,2051 03773 POINTVSM # RESOLVE THE POINTING DIRECTION VF INTO
020612,000418: 27,2052 03246 MIS # INITIAL S/C AXES (VF = POINTVSM)
020613,000419: 27,2053 77656 UNIT
020614,000420: 27,2054 00035 STORE 28D
020615,000421: # PD 28 29 30 31 32 33
020616,000422: 27,2055 53435 VXV UNIT # TAKE THE CROSS PRODUCT VF X VI
020617,000423: 27,2056 03765 SCAXIS # WHERE VI = SCAXIS
020618,000424: 27,2057 57400 BOV VCOMP
020619,000425: 27,2060 56170 PICKAXIS
020620,000426: 27,2061 17270 STODL COF # CHECK MAGNITUDE
020621,000427: 27,2062 00045 36D # OF CROSS PRODUCT
020622,000428: 27,2063 50025 DSU BMN # VECTOR, IF LESS
020623,000429: 27,2064 14415 DPB-14 # THAN B-14 ASSUME
020624,000430: 27,2065 56170 PICKAXIS # UNIT OPERATION
020625,000431: 27,2066 50375 VLOAD DOT # INVALID.
020626,000432: 27,2067 03765 SCAXIS
020627,000433: 27,2070 00035 28D
020628,000434: 27,2071 65552 SL1 ARCCOS
020629,000435: 27,2072 77624 COMPMATX CALL # NOW COMPUTE THE TRANSFORMATION FROM
020630,000436: 27,2073 44527 DELCOMP # FINAL S/C AXES TO INITIAL S/C AXES MFI
020631,000437: 27,2074 75160 AXC,1 AXC,2
020632,000438: 27,2075 03245 MIS # COMPUTE THE TRANSFORMATION FROM FINAL
020633,000439: 27,2076 02230 KEL # S/C AXES TO STABLE MEMBER AXES
020634,000440: 27,2077 77624 CALL # MFS = MIS MFI
020635,000441: 27,2100 44312 MXM3 # (IN PD LIST)
020636,000442:
020637,000443: 27,2101 51545 DLOAD ABS
020638,000444: 27,2102 00007 6 # MFS6 = SIN(CPSI) $2
020639,000445: 27,2103 50025 DSU BMN
020640,000446: 27,2104 14402 SINGIMLC # = SIN(59 DEGS) $2
020641,000447: 27,2105 56160 FINDGIMB # /CPSI/ LESS THAN 59 DEGS
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Page 486 |
020643,000449: # I.E. DESIRED ATTITUDE NOT IN GIMBAL LOCK
020644,000450:
020645,000451: 27,2106 51545 DLOAD ABS # CHECK TO SEE IF WE ARE POINTING
020646,000452: 27,2107 03765 SCAXIS # THE THRUST AXIS
020647,000453: 27,2110 51025 DSU BPL
020648,000454: 27,2111 14404 SINVEC1 # SIN 49.4 DEGS $2
020649,000455: 27,2112 56160 FINDGIMB # IF SO, WE ARE TRYING TO POINT IT INTO
020650,000456: 27,2113 77775 VLOAD # GIMBAL LOCK, ABORT COULD GO HERE
020651,000457: 27,2114 77626 STADR
020652,000458: 27,2115 50515 STOVL MIS +12D
020653,000459: 27,2116 77626 STADR # STORE MFS (IN PD LIST) IN MIS
020654,000460: 27,2117 50523 STOVL MIS +6
020655,000461: 27,2120 77626 STADR
020656,000462: 27,2121 50531 STOVL MIS
020657,000463: 27,2122 03254 MIS +6 # INNER GIMBAL AXIS IN FINAL S/C AXES
020658,000464: 27,2123 57444 BPL VCOMP # LOCATE THE IG AXIS DIRECTION CLOSEST TO
020659,000465: 27,2124 56125 IGSAMEX # FINAL X S/C AXIS
020660,000466:
020661,000467: 27,2125 50035 IGSAMEX VXV BMN # FIND THE SHORTEST WAY OF ROTATING THE
020662,000468: 27,2126 03765 SCAXIS # S/C OUT OF GIMBAL LOCK BY A ROTATION
020663,000469: 27,2127 56134 U=SCAXIS # ABOUT +- SCAXIS, I.E. IF (IG (SGN MFS3)
020664,000470: # X SCAXIS . XF) LESS THAN 0, U = SCAXIS
020665,000471: # OTHERWISE U = -SCAXIS
020666,000472:
020667,000473: 27,2130 57575 VLOAD VCOMP
020668,000474: 27,2131 03765 SCAXIS
020669,000475: 27,2132 37270 STCALL COF # ROTATE ABOUT -SCAXIS
020670,000476: 27,2133 56137 CHEKAXIS
020671,000477: 27,2134 77775 U=SCAXIS VLOAD
020672,000478: 27,2135 03765 SCAXIS
020673,000479: 27,2136 03270 STORE COF # ROTATE ABOUT + SCAXIS
020674,000480: 27,2137 51545 CHEKAXIS DLOAD ABS
020675,000481: 27,2140 03765 SCAXIS # SEE IF WE ARE POINTING THE AOT
020676,000482: 27,2141 51025 DSU BPL
020677,000483: 27,2142 14406 SINVEC2 # SIN 29.5 DEGS $2
020678,000484: 27,2143 56147 PICKANG1 # IF SO, ROTATE 50 DEGS ABOUT +- SCAXIS
020679,000485: 27,2144 52145 DLOAD GOTO # IF NOT, MUST BE POINTING THE TRANSPONDER
020680,000486: 27,2145 14412 VECANG2 # OR SOME VECTOR IN THE Y, OR Z PLANE
020681,000487: 27,2146 56151 COMPMFSN # IN THIS CASE ROTATE 35 DEGS TO GET OUT
020682,000488: # OF GIMBAL LOCK (VECANG2 $360)
020683,000489: 27,2147 77745 PICKANG1 DLOAD
020684,000490: 27,2150 14410 VECANG1 # = 50 DEGS $ 360
020685,000491: 27,2151 77624 COMPMFSN CALL
020686,000492: 27,2152 44527 DELCOMP # COMPUTE THE ROTATION ABOUT SCAXIS TO
020687,000493: 27,2153 75160 AXC,1 AXC,2 # BRING MFS OUT OF GIMBAL LOCK
020688,000494: 27,2154 03245 MIS
020689,000495: 27,2155 02230 KEL
020690,000496: 27,2156 77624 CALL # COMPUTE THE NEW TRANSFORMATION FROM
020691,000497: 27,2157 44312 MXM3 # DESIRED S/C AXES TO STABLE MEMBER AXES
020692,000498: # WHICH WILL ALIGN VI WITH VF AND AVOID
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020694,000500: # GIMBAL LOCK
020695,000501: 27,2160 45160 FINDGIMB AXC,1 CALL
020696,000502: 27,2161 00000 0 # EXTRACT THE COMMANDED CDU ANGLES FROM
020697,000503: 27,2162 44654 DCMTOCDU # THIS MATRIX
020698,000504: 27,2163 40234 RTB SETPD
020699,000505: 27,2164 21621 V1STO2S # CONVERT TO 2:S COMPLEMENT
020700,000506: 27,2165 00001 0
020701,000507: 27,2166 77650 GOTO
020702,000508: 27,2167 03324 VECQTEMP # RETURN TO CALLER
020703,000509:
020704,000510: 27,2170 50375 PICKAXIS VLOAD DOT # IF VF X VI = 0, FIND VF . VI
020705,000511: 27,2171 00035 28D
020706,000512: 27,2172 03765 SCAXIS
020707,000513: 27,2173 72240 BMN TLOAD
020708,000514: 27,2174 54354 ROT180
020709,000515: 27,2175 00032 25D
020710,000516: 27,2176 77650 GOTO # IF VF = VI, CDU DESIRED = PRESENT CDU
020711,000517: 27,2177 03324 VECQTEMP # PRESENT CDU ANGLES
020712,000518:
020713,000519: 35,2000 BANK 35
020714,000520: 26,2000 SETLOC MANUVER1
020715,000521: 26,2000 BANK
020716,000522: 26,2354 47375 ROT180 VLOAD VXV # IF VF, VI ANTIPARALLEL, 108 DEG ROTATION
020717,000523: 26,2355 03254 MIS +6 # IS REQUIRED. Y STABLE MEMBER AXIS IN
020718,000524: 26,2356 06522 HIDPHALF # INITIAL S/C AXES.
020719,000525: 26,2357 47256 UNIT VXV # FIND Y(SM) X X(I)
020720,000526: 26,2360 03765 SCAXIS # FIND UNIT(VI X UNIT(Y(SM) X X(I)))
020721,000527: 26,2361 40056 UNIT BOV # I.E. PICK A VECTOR IN THE PLANE OF X(I),
020722,000528: 26,2362 54376 PICKX # Y(SM) PERPENDICULAR TO VI
020723,000529: 26,2363 17270 STODL COF
020724,000530: 26,2364 00045 36D # CHECK MAGNITUDE
020725,000531: 26,2365 50025 DSU BMN # OF THIS VECTOR.
020726,000532: 26,2366 14415 DPB-14 # IF LESS THAN B-14,
020727,000533: 26,2367 54376 PICKX # PICK X-AXIS.
020728,000534: 26,2370 77775 VLOAD
020729,000535: 26,2371 03270 COF
020730,000536: 26,2372 17270 XROT STODL COF
020731,000537: 26,2373 06522 HIDPHALF
020732,000538: 26,2374 77650 GOTO
020733,000539: 26,2375 56072 COMPMATX
020734,000540: 26,2376 52175 PICKX VLOAD GOTO # PICK THE XAXIS IN THIS CASE
020735,000541: 26,2377 06522 HIDPHALF
020736,000542: 26,2400 54372 XROT
020737,000543: 26,2401 15555 35172 SINGIMLC 2DEC .4285836003 # = SIN(59) $2
020738,000544: 26,2403 14113 36326 SINVEC1 2DEC .3796356537 # = SIN(49.4) $2
020739,000545: 26,2405 07701 35703 SINVEC2 2DEC .2462117800 # = SIN(29.5) $2
020740,000546: 26,2407 04343 21616 VECANG1 2DEC .1388888889 # = 50 DEGREES $360
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020742,000548: 26,2411 03070 34344 VECANG2 2DEC .09722222222 # = 35 DEGREES $360
020743,000549:
020744,000550: 26,2413 00000 1BITDP OCT 0 # KEEP THIS BEFORE DPB(-14) *********
020745,000551: 26,2414 00001 DPB-14 OCT 00001
020746,000552: 26,2415 00000 OCT 00000
020747,000553:
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Page 489 |
020749,000555: # ROUTINE FOR INITIATING AUTOMATIC MANEUVER VIA KEYBOARD (V49)
020750,000556:
020751,000557: 34,2000 BANK 34
020752,000558: 23,2000 SETLOC R62
020753,000559: 23,2000 BANK
020754,000560: 23,2103 E6,1675 EBANK= BCDU
020755,000561:
020756,000562: 23,2103 COUNT* $$/R62
020757,000563:
020758,000564: 23,2103 23,2103 R62DISP EQUALS R62FLASH
020759,000565:
020760,000566: 23,2103 35010 R62FLASH CAF V06N22 # FLASH V06N22 AND
020761,000567: 23,2104 04616 TC BANKCALL # ICDU ANGLES
020762,000568: 23,2105 20477 CADR GOFLASH
020763,000569: 23,2106 15472 TCF ENDEXT # TERMINATE
020764,000570: 23,2107 12111 TCF GOMOVE # PROCEED
020765,000571: 23,2110 12103 TCF R62FLASH # ENTER
020766,000572:
020767,000573: # ASTRONAUT MAY LOAD NEW ICDUS AT THIS
020768,000574: # POINT
020769,000575: 23,2111 05504 GOMOVE TC UPFLAG # SET FOR 3-AXIS MANEUVER
020770,000576: 23,2112 00124 ADRES 3AXISFLG
020771,000577:
020772,000578: 23,2113 04616 TC BANKCALL
020773,000579: 23,2114 54123 CADR R60LEM
020774,000580: 23,2115 15472 TCF ENDEXT # END R62
020775,000581:
End of include-file R60,R62.agc. Parent file is MAIN.agc