Source Code
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This is an attempt to recreate Luminary 99 Rev 2, otherwise known as LUM99R2, from Luminary 99 Rev 1 and ephemeris data from Luminary 116. The differences are confined to the last 10-12 lines of the CONTROLLED CONSTANTS. Luminary 99 Rev 1 source-code was transcribed from a printout in the MIT Museum, while Luminary 116 source code was transcribed from a printout belonging to Don Eyles. AGC developer James Kernan, the "rope mother" for the Apollo 11 Lunar Module's AGC, explains as follows: "At the last minute, Dan Lickly, our chief engineer, appeared with ephemerides updates and it took two tries to get it right. The result was that we created Lum99 Revision 1 and Lum99 Revision 2." It is suspected that the former is what's in the MIT Museum, and the latter is what we are trying to recreate here. As for which revision actually flew in Apollo 11, all of the other available surviving evidence points to Rev 1 rather than to Rev 2, so we're just not sure! |
033795,000002: ## Copyright: Public domain.
033796,000003: ## Filename: THROTTLE_CONTROL_ROUTINES.agc
033797,000004: ## Purpose: Part of the source code for Luminary 1A build 099.
033798,000005: ## It is part of the source code for the Lunar Module's (LM)
033799,000006: ## Apollo Guidance Computer (AGC), for Apollo 11.
033800,000007: ## Assembler: yaYUL
033801,000008: ## Contact: HARTMUTH GUTSCHE <hgutsche@xplornet.com>.
033802,000009: ## Website: www.ibiblio.org/apollo.
033803,000010: ## Pages: 793-797
033804,000011: ## Mod history: 2009-05-20 HG Transcribed from page images.
033805,000012: ## 2010-12-31 JL Fixed page number comments.
033806,000013: ## 2016-12-16 RSB Proofed text comments with octopus/ProoferComments
033807,000014: ## and corrected the errors found.
033808,000015: ## 2017-03-03 RSB Snapshot of Luminary 99 Rev 1.
033809,000016: ## 2017-03-16 RSB Comment-text fixes identified in 5-way
033810,000017: ## side-by-side diff of Luminary 69/99/116/131/210.
033811,000018:
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Page 793 |
033813,000020: 31,2216 BANK 31
033814,000021: 31,2000 SETLOC FTHROT
033815,000022: 31,2000 BANK
033816,000023: 31,2216 E7,1612 EBANK= PIF
033817,000024: 31,2216 COUNT* $$/THROT
033818,000025:
033819,000026: # * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
033820,000027: # HERE FC, DESIRED THRUST, AND FP, PRESENT THRUST, UNWEIGHTED, ARE COMPUTED.
033821,000028:
033822,000029: 31,2216 31246 THROTTLE CA ABDELV # COMPUTE PRESENT ACCELERATION IN UNITS OF
033823,000030: 31,2217 00006 EXTEND # 2(-4) M/CS/CS, SAVING SERVICER TROUBLE
033824,000031: 31,2220 72417 MP /AF/CNST
033825,000032: 31,2221 00006 +3 EXTEND
033826,000033: 31,2222 23607 QXCH RTNHOLD
033827,000034: 31,2223 02400 AFDUMP TC MASSMULT
033828,000035: 31,2224 53470 DXCH FP # FP = PRESENT THRUST
033829,000036: 31,2225 00006 EXTEND
033830,000037: 31,2226 31464 DCA /AFC/
033831,000038: 31,2227 02400 TC MASSMULT
033832,000039: 31,2230 55615 TS FC # FC = THRUST DESIRED BY GUIDANCE
033833,000040: 31,2231 53466 DXCH FCODD # FCODD = WHAT IT IS GOING TO GET
033834,000041:
033835,000042: # IF IT HAS BEEN LESS THAN 3 SECONDS SINCE THE LAST THROTTLING, AUGMENT FP USING THE FWEIGHT CALCULATED THEN.
033836,000043:
033837,000044: 31,2232 41617 CS TTHROT # THIS CODING ASSUMES A FLATOUT WITHIN
033838,000045: 31,2233 60025 AD TIME1 # 80 SECONDS BEFORE FIRST THROTTLE CALL
033839,000046: 31,2234 74733 MASK POSMAX
033840,000047: 31,2235 40000 COM
033841,000048: 31,2236 65002 AD 3SECS
033842,000049: 31,2237 00006 EXTEND
033843,000050: 31,2240 62244 BZMF WHERETO # BRANCH IF (TIME1-TTHROT +1) > 3 SECONDS
033844,000051: 31,2241 00006 EXTEND
033845,000052: 31,2242 31611 DCA FWEIGHT
033846,000053: 31,2243 21470 DAS FP
033847,000054:
033848,000055: # THIS LOGIC DETERMINES THE THROTTLING IN THE REGION 10% - 94%. THE MANUAL THROTTLE, NOMINALLY SET AT
033849,000056: # MINIMUM BY ASTRONAUT OR MISSION CONTROL PROGRAMS, PROVIDES THE LOWER BOUND. A STOP IN THE THROTTLE HARDWARE
033850,000057: # PROVIDES THE UPPER.
033851,000058:
033852,000059: 31,2244 35014 WHERETO CA EBANK5 # INITIALIZE L*WCR*T AND H*GHCR*T FROM
033853,000060: 31,2245 54003 TS EBANK # PAD LOADED ERASABLES IN W-MATRIX
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Page 794 |
033855,000062: 31,2246 E5,1506 EBANK= LOWCRIT
033856,000063: 31,2246 00006 EXTEND
033857,000064: 31,2247 31507 DCA LOWCRIT
033858,000065: 31,2250 52131 DXCH L*WCR*T
033859,000066: 31,2251 35016 CA EBANK7
033860,000067: 31,2252 54003 TS EBANK
033861,000068: 31,2253 E7,1612 EBANK= PIF
033862,000069: 31,2253 44755 CS ZERO # INITIALIZE PIFPSET
033863,000070: 31,2254 55606 TS PIFPSET
033864,000071: 31,2255 40131 CS H*GHCR*T
033865,000072: 31,2256 61620 AD FCOLD
033866,000073: 31,2257 00006 EXTEND
033867,000074: 31,2260 62272 BZMF LOWFCOLD # BRANCH IF FCOLD < OR = HIGHCRIT
033868,000075: 31,2261 40130 CS L*WCR*T
033869,000076: 31,2262 61465 AD FCODD
033870,000077: 31,2263 00006 EXTEND
033871,000078: 31,2264 62267 BZMF FCOMPSET # BRANCH IF FC < OR = LOWCRIT
033872,000079: 31,2265 31467 CA FP # SEE NOTE 1
033873,000080: 31,2266 12277 TCF FLATOUT1
033874,000081:
033875,000082: 31,2267 42002 FCOMPSET CS FMAXODD # SEE NOTE 2
033876,000083: 31,2270 61467 AD FP
033877,000084: 31,2271 12301 TCF FLATOUT2
033878,000085:
033879,000086: 31,2272 40131 LOWFCOLD CS H*GHCR*T
033880,000087: 31,2273 61465 AD FCODD
033881,000088: 31,2274 00006 EXTEND
033882,000089: 31,2275 62302 BZMF DOPIF # BRANCH IF FC < OR = HIGHCRIT
033883,000090:
033884,000091: 31,2276 32003 CA FMAXPOS # NO: THROTTLE-UP
033885,000092: 31,2277 53466 FLATOUT1 DXCH FCODD
033886,000093: 31,2300 34737 CA FEXTRA
033887,000094: 31,2301 55606 FLATOUT2 TS PIFPSET
033888,000095:
033889,000096: # NOTE 1 FC IS SET EQUAL TO FP SO PIF WILL BE ZERO. THIS IS DESIRABLE
033890,000097: # AS THERE IS ACTUALLY NO THROTTLE CHANGE.
033891,000098:
033892,000099: # NOTE2 HERE, SINCE WE ARE ABOUT TO RETURN TO THE THROTTLEABLE REGION
033893,000100: # (BELOW 55%) THE QUANTITY -(FMAXODD-FP) IS COMPUTED AND PUT
033894,000101: # INTO PIFPSET TO COMPENSATE FOR THE DIFFERENCE BETWEEN THE
033895,000102: # NUMBER OF BITS CORRESPONDING TO FULL THROTTLE (FMAXODD) AND THE
033896,000103: # NUMBER CORRESPONDING TO ACTUAL THRUST (FP). THUS THE TOTAL
033897,000104: # THROTTLE COMMAND PIF = FC - FP - (FMAXODD - FP) = FC - FMAXODD.
033898,000105:
033899,000106: 31,2302 03740 DOPIF TC FASTCHNG
033900,000107: 31,2303 00006 EXTEND
033901,000108: 31,2304 31466 DCA FCODD
033902,000109: 31,2305 55620 TS FCOLD
033903,000110: 31,2306 53613 DXCH PIF
033904,000111: 31,2307 00006 EXTEND
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Page 795 |
033906,000113: 31,2310 41470 DCS FP
033907,000114: 31,2311 21613 DAS PIF # PIF = FC - FP, NEVER EQUALS +0
033908,000115:
033909,000116: 31,2312 31612 DOIT CA PIF
033910,000117: 31,2313 61606 AD PIFPSET # ADD IN PIFPSET, WITHOUT CHANGING PIF
033911,000118: 31,2314 55614 TS PSEUDO55
033912,000119: 31,2315 54055 TS THRUST
033913,000120: 31,2316 34750 CAF BIT4
033914,000121: 31,2317 00006 EXTEND
033915,000122: 31,2320 05014 WOR CHAN14
033916,000123: 31,2321 30025 CA TIME1
033917,000124: 31,2322 55617 TS TTHROT
033918,000125:
033919,000126: # SINCE /AF/ IS NOT AN INSTANTANEOUS ACCELERATION, BUT RATHER AN "AVERAGE" OF THE ACCELERATION LEVELS DURING
033920,000127: # THE PRECEEDING PIPA INTERVAL, AND SINCE FP IS COMPUTED DIRECTLY FROM /AF/, FP IN ORDER TO CORRESPOND TO THE
033921,000128: # ACTUAL THRUST LEVEL AT THE END OF THE INTERVAL MUST BE WEIGHTED BY
033922,000129:
033923,000130: # PIF(PPROCESS + TL) PIF /PIF/
033924,000131: # FWEIGHT = ------------------ + -------------
033925,000132: # PGUID 2 PGUID FRATE
033926,000133:
033927,000134: # WHERE PPROCESS IS THE TIME BETWEEN PIPA READING AND THE START OF THROTTLING, PGUID IS THE GUIDANCE PERIOD, AND
033928,000135: # FRATE IS THE THROTTLING RATE (32 UNITS PER CENTISECOND). PGUID IS EITHER 1 OR 2 SECONDS. THE "TL" IN THE
033929,000136: # FIRST TERM REPRESENTS THE ENGINE'S RESPONSE LAG. HERE FWEIGHT IS COMPUTED FOR USE NEXT PASS.
033930,000137:
033931,000138: 31,2323 31762 CA THISTPIP +1 # INITIALIZE FWEIGHT COMP AS IF FOR P66
033932,000139: 31,2324 54130 TS BUF
033933,000140:
033934,000141: 31,2325 41011 CS MODREG # ARE WE IN FACT IN P66?
033935,000142: 31,2326 62501 AD DEC66
033936,000143: 31,2327 00006 EXTEND
033937,000144: 31,2330 12335 BZF FWCOMP # YES
033938,000145:
033939,000146: 31,2331 31235 CA PIPTIME +1 # NO: INITIALIZE FOR TWO SECOND PERIOD
033940,000147: 31,2332 54130 TS BUF
033941,000148: 31,2333 35003 CAF 4SECS
033942,000149: 31,2334 12336 TCF FWCOMP +1
033943,000150:
033944,000151: 31,2335 35000 FWCOMP CAF 2SECS
033945,000152: 31,2336 54002 +1 TS Q
033946,000153: 31,2337 00006 EXTEND
033947,000154: 31,2340 74746 MP BIT6
033948,000155: 31,2341 22131 LXCH BUF +1
033949,000156: 31,2342 40130 CS BUF # TIME OF LAST PIPA READING.
033950,000157: 31,2343 60025 AD TIME1
033951,000158: 31,2344 62004 AD THROTLAG # COMPENSATE FOR ENGINE RESPONSE LAG
033952,000159: 31,2345 74357 MASK LOW8 # MAKE SURE SMALL AND POSITIVE
033953,000160: 31,2346 22007 ZL
033954,000161: 31,2347 00006 EXTEND
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Page 796 |
033956,000163: 31,2350 10002 DV Q
033957,000164: 31,2351 00006 EXTEND
033958,000165: 31,2352 71612 MP PIF
033959,000166: 31,2353 60000 DOUBLE
033960,000167: 31,2354 53611 DXCH FWEIGHT
033961,000168: 31,2355 11612 CCS PIF
033962,000169: 31,2356 64753 AD ONE
033963,000170: 31,2357 12361 TCF +2
033964,000171: 31,2360 64753 AD ONE
033965,000172: 31,2361 00006 EXTEND
033966,000173: 31,2362 71612 MP PIF
033967,000174: 31,2363 00006 EXTEND
033968,000175: 31,2364 10131 DV BUF +1
033969,000176: 31,2365 22007 ZL
033970,000177: 31,2366 21611 DAS FWEIGHT
033971,000178:
033972,000179: 31,2367 01607 THDUMP TC RTNHOLD
033973,000180:
033974,000181: # FLATOUT THROTTLES UP THE DESCENT ENGINE, AND IS CALLED AS A BASIC SUBROUTINE.
033975,000182:
033976,000183: 31,2370 34737 FLATOUT CAF BIT13 # 4096 PULSES
033977,000184: 31,2371 55606 WHATOUT TS PIFPSET # USE PIFPSET SO FWEIGHT WILL BE ZERO
033978,000185: 31,2372 44755 CS ZERO
033979,000186: 31,2373 55620 TS FCOLD
033980,000187: 31,2374 55612 TS PIF
033981,000188: 31,2375 00006 EXTEND
033982,000189: 31,2376 23607 QXCH RTNHOLD
033983,000190: 31,2377 12312 TCF DOIT
033984,000191:
033985,000192: # MASSMULT SCALES ACCELERATION, ARRIVING IN A AND L IN UNITS OF 2(-4) M/CS/CS, TO FORCE IN PULSE UNITS.
033986,000193:
033987,000194: 31,2400 00006 MASSMULT EXTEND
033988,000195: 31,2401 22130 QXCH BUF
033989,000196: 31,2402 52155 DXCH MPAC
033990,000197: 31,2403 07103 TC DMP
033991,000198: 31,2404 01244 ADRES MASS
033992,000199: 31,2405 07103 TC DMP # LEAVES PROPERLY SCALED FORCE IM MPAC
033993,000200: 31,2406 02005 ADRES SCALEFAC
033994,000201: 31,2407 07257 TC TPAGREE
033995,000202: 31,2410 30154 CA MPAC
033996,000203: 31,2411 00006 EXTEND
033997,000204: 31,2412 12415 BZF +3
033998,000205: 31,2413 34733 CAF POSMAX
033999,000206: 31,2414 00130 TC BUF
034000,000207: 31,2415 52156 DXCH MPAC +1
034001,000208: 31,2416 00130 TC BUF
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Page 797 |
034003,000210: # CONSTANTS:-
034004,000211:
034005,000212: 31,2417 4737 FEXTRA = BIT13 # FEXT +5.13309020 E+4
034006,000213:
034007,000214: 31,2417 04143 /AF/CNST DEC .13107
034008,000215:
034009,000216: # * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
End of include-file THROTTLE_CONTROL_ROUTINES.agc. Parent file is MAIN.agc