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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027736,000002: ## Copyright: Public domain.
027737,000003: ## Filename: GROUND_TRACKING_DETERMINATION_PROGRAM_-_P21.agc
027738,000004: ## Purpose: A section of Luminary revision 97.
027739,000005: ## It is part of the reconstructed source code for the
027740,000006: ## second release of the flight software for the Lunar
027741,000007: ## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 11.
027742,000008: ## It was created to fix two incorrect ephemeris constants in
027743,000009: ## Luminary 96, as described by anomaly report LNY-59.
027744,000010: ## The code has been recreated from a copy of Luminary 99
027745,000011: ## revision 001, using asterisks indicating changed lines in
027746,000012: ## the listing and Luminary Memos #83 and #85, which list
027747,000013: ## changes between Luminary 97 and 98, and 98 and 99. The
027748,000014: ## code has been adapted such that the resulting bugger words
027749,000015: ## exactly match those specified for Luminary 97 in NASA drawing
027750,000016: ## 2021152D, which gives relatively high confidence that the
027751,000017: ## reconstruction is correct.
027752,000018: ## Reference: pp. 654-657
027753,000019: ## Assembler: yaYUL
027754,000020: ## Contact: Ron Burkey <info@sandroid.org>.
027755,000021: ## Website: www.ibiblio.org/apollo/index.html
027756,000022: ## Mod history: 2019-07-28 MAS Created from Luminary 99.
027757,000023:
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Page 654
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027759,000025: # GROUND TRACKING DETERMINATION PROGRAM P21
027760,000026: # PROGRAM DESCRIPTION
027761,000027: # MOD NO - 1
027762,000028: # MOD BY - N. M. NEVILLE
027763,000029:
027764,000030: # FUNCTIONAL DECRIPTION -
027765,000031: # TO PROVIDE THE ASTRONAUT DETAILS OF THE LM OR CSM GROUND TRACK WITHOUT
027766,000032: # THE NEED FOR GROUND COMMUNICATION (REQUESTED BY DSKY).
027767,000033:
027768,000034: # CALLING SEQUENCE -
027769,000035: # ASTRONAUT REQUEST THROUGH DSKY V37E21E
027770,000036:
027771,000037: # SUBROUTINES CALLED -
027772,000038: # GOPERF4
027773,000039: # GOFLASH
027774,000040: # THISPREC
027775,000041: # OTHPREC
027776,000042: # LAT-LONG
027777,000043:
027778,000044: # NORMAL EXIT MODES -
027779,000045: # ASTRONAUT REQUEST TROUGH DSKY TO TERMINATE PROGRAM V34E
027780,000046:
027781,000047: # ALARM OR ABORT EXIT MODES -
027782,000048: # NONE
027783,000049:
027784,000050: # OUTPUT -
027785,000051: # OCTAL DISPLAY OF OPTION CODE AND VEHICLE WHOSE GROUND TRACK IS TO BE
027786,000052: # COMPUTED
027787,000053: # OPTION CODE 00002
027788,000054: # THIS 00001
027789,000055: # OTHER 00002
027790,000056: # DECIMAL DISPLAY OF TIME TO BE INTEGRATED TO HOURS, MINUTES, SECONDS
027791,000057: # DECIMAL DISPLAY OF LAT,LONG,ALT
027792,000058:
027793,000059: # ERASABLE INITIALIZATION REQUIRED
027794,000060: # AX0 2DEC 4.652459653 E-5 RADIANS %68-69 CONSTANTS"
027795,000061: # -AY0 2DEC 2.147535898 E-5 RADIANS
027796,000062: # AZ0 2DEC .7753206164 REVOLUTIONS
027797,000063: # FOR LUNAR ORBITS 504LM VECTOR IS NEEDED
027798,000064: # 504LM 2DEC -2.700340600 E-5 RADIANS
027799,000065: # 504LM _2 2DEC -7.514128400 E-4 RADIANS
027800,000066: # 504LM _4 2DEC _2.553198641 E-4 RADIANS
027801,000067:
027802,000068: # NONE
027803,000069:
027804,000070: # DEBRIS
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Page 655
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027806,000072: # CENTRALS - A,Q,L
027807,000073: # OTHER - THOSE USED BY THE ABOVE LISTED SUBROUTINES
027808,000074: # SEE LEMPREC, LAT-LONG
027809,000075:
027810,000076: 35,2545 30,2000 SBANK= LOWSUPER # FOR LOW 2CADR'S.
027811,000077:
027812,000078: 33,2200 BANK 33
027813,000079: 24,2000 SETLOC P20S
027814,000080: 24,2000 BANK
027815,000081:
027816,000082: 24,3505 E7,1762 EBANK= P21TIME
027817,000083: 24,3505 COUNT* $$/P21
027818,000084: 24,3505 34753 PROG21 CAF ONE
027819,000085: 24,3506 55145 TS OPTION2 # ASSUMED VEHICLE IS LM, R2 = 00001
027820,000086: 24,3507 34752 CAF BIT2 # OPTION 2
027821,000087: 24,3510 04616 TC BANKCALL
027822,000088: 24,3511 20633 CADR GOPERF4
027823,000089: 24,3512 06001 TC GOTOPOOH # TERMINATE
027824,000090: 24,3513 03515 TC +2 # PROCEED VALUE OF ASSUMED VEHICLE OK
027825,000091: 24,3514 03507 TC -5 # R2 LOADED THROUGH DSKY
027826,000092: 24,3515 33665 P21PROG1 CAF V6N34 # LOAD DESIRED TIME OF LAT-LONG.
027827,000093: 24,3516 04616 TC BANKCALL
027828,000094: 24,3517 20476 CADR GOFLASH
027829,000095: 24,3520 06001 TC GOTOPOOH # TERM
027830,000096: 24,3521 03523 TC +2 # PROCEED VALUES OK
027831,000097: 24,3522 03515 TC -5 # TIME LOADED THROUGH DSKY
027832,000098: 24,3523 06037 TC INTPRET
027833,000099: 24,3524 77745 DLOAD
027834,000100: 24,3525 01046 DSPTEM1
027835,000101: 24,3526 34041 STCALL TDEC1 # INTEGRATE TO TIME SPECIFIED IN TDEC
027836,000102: 24,3527 27414 INTSTALL
027837,000103: 24,3530 43014 BON CLEAR
027838,000104: 24,3531 00304 P21FLAG
027839,000105: 24,3532 51550 P21CONT # ON --- RECYCLE USING BASE VECTOR
027840,000106: 24,3533 01674 VINTFLAG # OFF -- 1ST PASS CALL BASE VECTOR
027841,000107: 24,3534 70535 SLOAD SR1
027842,000108: 24,3535 01146 OPTION2
027843,000109: 24,3536 43030 BHIZ SET
027844,000110: 24,3537 51541 +2 # ZERO -- THIS VEHICLE (LM)
027845,000111: 24,3540 01474 VINTFLAG # ONE -- OTHER VEHICLE (CM)
027846,000112: 24,3541 43014 CLEAR CLEAR
027847,000113: 24,3542 01676 DIM0FLAG
027848,000114: 24,3543 01673 INTYPFLG # PRECISION
027849,000115: 24,3544 77624 CALL
027850,000116: 24,3545 27134 INTEGRV # CALCULATE
027851,000117: 24,3546 77650 GOTO # -AND
027852,000118: 24,3547 51571 P21VSAVE # -SAVE BASE VECTOR
027853,000119: 24,3550 77775 P21CONT VLOAD
027854,000120: 24,3551 03676 P21BASER # RECYCLE -- INTEG FROM BASE VECTOR
027855,000121: 24,3552 25535 STOVL RCV # --POS
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Page 656
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027857,000123: 24,3553 03704 P21BASEV
027858,000124: 24,3554 15543 STODL VCV # --VEL
027859,000125: 24,3555 03763 P21TIME
027860,000126: 24,3556 01517 STORE TET # --TIME
027861,000127: 24,3557 43014 CLEAR CLEAR
027862,000128: 24,3560 01676 DIM0FLAG
027863,000129: 24,3561 00263 MOONFLAG
027864,000130: 24,3562 53135 SLOAD BZE
027865,000131: 24,3563 01164 P21ORIG
027866,000132: 24,3564 51567 +3 # ZERO = EARTH
027867,000133: 24,3565 77614 SET # ---2 = MOON
027868,000134: 24,3566 00063 MOONFLAG
027869,000135: 24,3567 77624 +3 CALL
027870,000136: 24,3570 27107 INTEGRVS
027871,000137: 24,3571 77745 P21VSAVE DLOAD # SAVE CURRENT BASE VECTOR
027872,000138: 24,3572 00015 TAT
027873,000139: 24,3573 27763 STOVL P21TIME # --TIME
027874,000140: 24,3574 00017 RATT1
027875,000141: 24,3575 27676 STOVL P21BASER # --POS B-29 OR B-27
027876,000142: 24,3576 00025 VATT1
027877,000143: 24,3577 03704 STORE P21BASEV # --VEL B-07 OR B-05
027878,000144: 24,3600 53646 ABVAL SL*
027879,000145: 24,3601 57576 0,2
027880,000146: 24,3602 27712 STOVL P21VEL # VEL/ FOR N91 DISP
027881,000147: 24,3603 00001 RATT
027882,000148: 24,3604 50256 UNIT DOT
027883,000149: 24,3605 00007 VATT # U(R).V
027884,000150: 24,3606 67471 DDV ASIN # U(R).U(V)
027885,000151: 24,3607 03712 P21VEL
027886,000152: 24,3610 03714 STORE P21GAM # SIN-1 U(R).U(V) , -90 TO &90
027887,000153: 24,3611 67334 SXA,2 SLOAD
027888,000154: 24,3612 01163 P21ORIG # 0 = EARTH
027889,000155: 24,3613 01146 OPTION2
027890,000156: 24,3614 46142 SR1 BHIZ
027891,000157: 24,3615 51620 +3
027892,000158: 24,3616 77650 GOTO
027893,000159: 24,3617 51623 +4
027894,000160: 24,3620 77614 +3 BON
027895,000161: 24,3621 04307 SURFFLAG
027896,000162: 24,3622 51625 P21DSP
027897,000163: 24,3623 77614 +4 SET
027898,000164: 24,3624 00064 P21FLAG
027899,000165: 24,3625 67214 P21DSP CLEAR SLOAD # GENERATE DISPLAY DATA
027900,000166: 24,3626 01663 LUNAFLAG
027901,000167: 24,3627 00050 X2
027902,000168: 24,3630 43054 BZE SET
027903,000169: 24,3631 51633 +2 # 0 = EARTH
027904,000170: 24,3632 01463 LUNAFLAG
027905,000171: 24,3633 77775 VLOAD
027906,000172: 24,3634 00001 RATT
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Page 657
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027908,000174: 24,3635 16032 STODL ALPHAV
027909,000175: 24,3636 00015 TAT
027910,000176: 24,3637 45014 CLEAR CALL
027911,000177: 24,3640 00662 ERADFLAG
027912,000178: 24,3641 26351 LAT-LONG
027913,000179: 24,3642 77605 DMP # MPAC = ALT, METERS B-29
027914,000180: 24,3643 11667 K.01
027915,000181: 24,3644 03716 STORE P21ALT # ALT/100 FOR N91 DISP
027916,000182: 24,3645 77776 EXIT
027917,000183: 24,3646 33664 CAF V06N43 # DISPLAY LAT, LONG, ALT
027918,000184: 24,3647 04616 TC BANKCALL # LAT, LONG = 1/2 REVS B0
027919,000185: 24,3650 20476 CADR GOFLASH # ALT = KM B14
027920,000186: 24,3651 06001 TC GOTOPOOH # TERM
027921,000187: 24,3652 06001 TC GOTOPOOH
027922,000188: 24,3653 06037 TC INTPRET # V32E RECYCLE
027923,000189: 24,3654 43345 DLOAD DAD
027924,000190: 24,3655 03763 P21TIME
027925,000191: 24,3656 11663 600SEC # 600 SECONDS OR 10 MIN
027926,000192: 24,3657 01046 STORE DSPTEM1
027927,000193: 24,3660 77634 RTB
027928,000194: 24,3661 51515 P21PROG1
027929,000195: 24,3662 00003 25140 600SEC 2DEC 60000 B-28 # 10 MIN
027930,000196:
027931,000197: 24,3664 01453 V06N43 VN 00643
027932,000198: 24,3665 01442 V6N34 VN 00634
027933,000199: 24,3666 00243 32703 K.01 2DEC .01
027934,000200:
End of include-file GROUND_TRACKING_DETERMINATION_PROGRAM_-_P21.agc. Parent file is MAIN.agc