Source Code
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These source-code files are part of a reconstructed copy of Luminary 97, the
second release of the Apollo 11 Lunar Module (LM) Apollo Guidance Computer
(AGC) software. It was created to fix two incorrect ephemeris constants in
Luminary 96, as described by anomaly report LNY-59.
The reconstruction began with source code of Luminary 99 revision 1 previously
transcribed from a digitized copy of that program. The code was then updated
by undoing changes described in original Luminary memos 83 and 85, using asterisks
indicating changed lines in the listing as a guide. The reconstruction was
verified by matching memory-bank checksums to those listed in drawing 2021152D.
Note that page numbers in the reconstructed code match those on the Luminary 099
revision 001 printout, although the added code would likely have changed page
numbers for a real Luminary 97 listing.
Comments from the original source code are prefixed with a single '#' symbol,
whereas comments added later are prefixed by "##" or "###". Report any errors
noted by creating an
issue report at the Virtual AGC
project's GitHub repository.
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027575,000002: ## Copyright: Public domain.
027576,000003: ## Filename: LAMBERT_AIMPOINT_GUIDANCE.agc
027577,000004: ## Purpose: A section of Luminary revision 97.
027578,000005: ## It is part of the reconstructed source code for the
027579,000006: ## second release of the flight software for the Lunar
027580,000007: ## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 11.
027581,000008: ## It was created to fix two incorrect ephemeris constants in
027582,000009: ## Luminary 96, as described by anomaly report LNY-59.
027583,000010: ## The code has been recreated from a copy of Luminary 99
027584,000011: ## revision 001, using asterisks indicating changed lines in
027585,000012: ## the listing and Luminary Memos #83 and #85, which list
027586,000013: ## changes between Luminary 97 and 98, and 98 and 99. The
027587,000014: ## code has been adapted such that the resulting bugger words
027588,000015: ## exactly match those specified for Luminary 97 in NASA drawing
027589,000016: ## 2021152D, which gives relatively high confidence that the
027590,000017: ## reconstruction is correct.
027591,000018: ## Reference: pp. 651-653
027592,000019: ## Assembler: yaYUL
027593,000020: ## Contact: Ron Burkey <info@sandroid.org>.
027594,000021: ## Website: www.ibiblio.org/apollo/index.html
027595,000022: ## Mod history: 2019-07-28 MAS Created from Luminary 99.
027596,000023:
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Page 651
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027598,000025:
027599,000026: # GENERAL LAMBERT AIMPOINT GUIDANCE **
027600,000027: # WRITTEN BY RAMA M AIYAWAR
027601,000028:
027602,000029: # PROGRAM P-31 DESCRIPTION **
027603,000030:
027604,000031: # 1. TO ACCEPT TARGETING PARAMETERS OBTAINED FROM A SOURCE EXTERNAL
027605,000032: # TO THE LEM AND COMPUTE THERE FROM THE REQUIRED-VELOCITY AND
027606,000033: # OTHER INITIAL CONDITIONS REQUIRED BY LM FOR DESIRED MANEUVER.
027607,000034: # THE TARGETING PARAMETERS ARE TIG (TIME OF IGNITION), TARGET
027608,000035: # VECTOR (RTARG), AND THE TIME FROM TIG UNTIL THE TARGET IS
027609,000036: # REACHED (DELLT4), DESIRED TIME OF FLIGHT FROM RINIT TO RTARG..
027610,000037:
027611,000038: # ASSUMPTIONS **
027612,000039:
027613,000040: # 1. THE TARGET PARAMETERS MAY HAVE BEEN LOADED PRIOR TO THE
027614,000041: # EXECUTION OF THIS PROGRAM.
027615,000042: # 2. THIS PROGRAM IS APPLICABLE IN EITHER EARTH OR LUNAR ORBIT.
027616,000043: # 3. THIS PROGRAM IS DESIGNED FOR ONE-MAN OPERATION, AND SHOULD
027617,000044: # BE SELECTED BY THE ASTRONAUT BY DSKY ENTRY V37 E31.
027618,000045:
027619,000046: # SUBROUTINES USED **
027620,000047: #
027621,000048: # MANUPARM, TTG/N35, R02BOTH, MIDGIM, DISPMGA, FLAGDOWN, BANKCALL,
027622,000049: # GOTOPOOH, ENDOFJOB, PHASCHNG, GOFLASHR, GOFLASH.
027623,000050:
027624,000051: # MANUPARM CALCULATES APOGEE, PERIGEE ALTITUDES AND DELTAV DESIRED
027625,000052: # FOR THE MANEUVER.
027626,000053:
027627,000054: # TTG/N35 CLOCKTASK - UPDATES CLOCK.
027628,000055:
027629,000056: # MIDGIM CALCULATES MIDDLE GIMBAL ANGLE FOR DISPLAY.
027630,000057:
027631,000058: # R02BOTH IMU - STATUS CHECK ROUTINE.
027632,000059:
027633,000060: # DISPLAYS USED IN P-31LM **
027634,000061:
027635,000062: # V06N33 DISPLAY SOTRED TIG (IN HRS. MINS. SECS)
027636,000063: # V06N42 DISPLAY APOGEE, PERIGEE, DELTAV.
027637,000064: # V16N35 DISPLAY TIME FROM TIG.
027638,000065: # V06N45 TIME FROM IGNITION AND MIDDLE GIMBAL ANGLE.
027639,000066:
027640,000067: # ERASABLE INITIALIZATION REQUIRED **
027641,000068:
027642,000069: # TIG TIME OF IGNITION DP (B+28) CS.
027643,000070:
027644,000071: # DELLT4 DESIRED TIME OF FLIGHT DP (B+28) CS
027645,000072: # FROM RINIT TO RTARG.
027646,000073:
027647,000074: # RTARG RADIUS VECTOR OF TARGET POSITION VECTOR
027648,000075: # RADIUS VECTOR SCALED TO (B+29)METERS IF EARTH ORBIT
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Page 652
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027650,000077: # RADIUS VECTOR SCALED TO (B+27)METERS IF MOON ORBIT
027651,000078:
027652,000079: # OUTPUT **
027653,000080:
027654,000081: # HAPO APOGEE ALTITUDE
027655,000082: # HPER PERIGEE ALTITUDE
027656,000083: # VGDISP MAG. OF DELTAV FOR DISPLAY, SCALING B+7 M/CS EARTH
027657,000084: # MAG. OF DELTAV FOR DISPLAY, SCALING B+5 M/CS MOON
027658,000085: # MIDGIM MIDDLE GIMBAL ANGLE
027659,000086: # XDELVFLG RESETS XDELVFLG FOR LAMBERT VG COMPUTATIONS
027660,000087:
027661,000088: # ALARMS OR ABORTS NONE **
027662,000089:
027663,000090: # RESTARTS ARE VIA GROUP 4 **
027664,000091:
027665,000092: 35,2000 SETLOC GLM
027666,000093: 35,2000 BANK
027667,000094:
027668,000095: 35,2450 E7,1470 EBANK= SUBEXIT
027669,000096:
027670,000097: 35,2450 COUNT* $$/P31
027671,000098: 35,2450 02361 P31 TC P20FLGON
027672,000099: 35,2451 32025 CAF V06N33 # TIG
027673,000100: 35,2452 03712 TC VNPOOH
027674,000101: 35,2453 06037 TC INTPRET
027675,000102: 35,2454 71214 CLEAR DLOAD
027676,000103: 35,2455 00670 UPDATFLG
027677,000104: 35,2456 03442 TIG
027678,000105: 35,2457 34041 STCALL TDEC1 # INTEGRATE STATE VECTORS TO TIG
027679,000106: 35,2460 27057 LEMPREC
027680,000107: 35,2461 40375 VLOAD SETPD
027681,000108: 35,2462 00001 RATT
027682,000109: 35,2463 00001 0D
027683,000110: 35,2464 03642 STORE RTIG
027684,000111: 35,2465 26323 STOVL RINIT
027685,000112: 35,2466 00007 VATT
027686,000113: 35,2467 03650 STORE VTIG
027687,000114: 35,2470 16331 STODL VINIT
027688,000115: 35,2471 32420 P30ZERO
027689,000116: 35,2472 65206 PUSH PDDL # E4 AND NUMIT = 0
027690,000117: 35,2473 03452 DELLT4
027691,000118: 35,2474 66015 DAD SXA,1
027692,000119: 35,2475 03442 TIG
027693,000120: 35,2476 02776 RTX1
027694,000121: 35,2477 03631 STORE TPASS4
027695,000122: 35,2500 45134 SXA,2 CALL
027696,000123: 35,2501 02777 RTX2
027697,000124: 35,2502 22000 INITVEL
027698,000125: 35,2503 41575 VLOAD PUSH
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Page 653
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027700,000127: 35,2504 02366 DELVEET3
027701,000128: 35,2505 03656 STORE DELVSIN
027702,000129: 35,2506 43046 ABVAL CLEAR
027703,000130: 35,2507 01267 XDELVFLG
027704,000131: 35,2510 37664 STCALL VGDISP
027705,000132: 35,2511 15733 GET.LVC
027706,000133: 35,2512 63375 VLOAD PDVL
027707,000134: 35,2513 03642 RTIG
027708,000135: 35,2514 02337 VIPRIME
027709,000136: 35,2515 77624 CALL
027710,000137: 35,2516 46316 PERIAPO1
027711,000138: 35,2517 77624 CALL
027712,000139: 35,2520 46426 SHIFTR1
027713,000140: 35,2521 77624 CALL # LIMIT DISPLAY TO 9999.9 N. MI.
027714,000141: 35,2522 45636 MAXCHK
027715,000142: 35,2523 16321 STODL HPER
027716,000143: 35,2524 00005 4D
027717,000144: 35,2525 77624 CALL
027718,000145: 35,2526 46426 SHIFTR1
027719,000146: 35,2527 77624 CALL # LIMIT DISPLAY TO 9999.9 N. MI.
027720,000147: 35,2530 45636 MAXCHK
027721,000148: 35,2531 02317 STORE HAPO
027722,000149: 35,2532 77776 EXIT
027723,000150: 35,2533 33727 CAF V06N81 # DELVLVC
027724,000151: 35,2534 03712 TC VNPOOH
027725,000152: 35,2535 32026 CAF V06N42 # HAPO, HPER, VGDISP
027726,000153: 35,2536 03712 TC VNPOOH
027727,000154: 35,2537 06037 TC INTPRET
027728,000155: 35,2540 45014 REVN1645 SET CALL # TRKMKCNT, TTOGO, +MGA
027729,000156: 35,2541 01071 FINALFLG
027730,000157: 35,2542 73606 VN1645
027731,000158: 35,2543 77650 GOTO
027732,000159: 35,2544 72540 REVN1645
027733,000160:
End of include-file LAMBERT_AIMPOINT_GUIDANCE.agc. Parent file is MAIN.agc