Source Code
![]() |
These source-code files were from the printout at the MIT Museum, with many thanks
to Deborah Douglas, the Museum's Curator of Science and Technology, for releasing
it to us. The printout was digitally photographed by Paul Fjeld. A team of
volunteers transcribed the source code manually from these images or, where
appropriate, modified already-transcribed but similar source Luminary 131 (Apollo 13)
source code to agree with the images from the printout. Note that the page images
presented online are of reduced quality, and that higher-quality images
are available. Report any conversion errors or legibility
problems in page images to info@sandroid.org.
Notations on the program listing read, in part:GAP: ASSEMBLE REVISION 001 OF AGC PROGRAM LMY99 BY NASA 2021112-061 20'35 OCT. 28,1968Note that the date is the date of the printout, not the date of the program revision. |
028020,000002: ## Copyright: Public domain.
028021,000003: ## Filename: GROUND_TRACKING_DETERMINATION_PROGRAM.agc
028022,000004: ## Purpose: Part of the source code for Luminary 1A build 099.
028023,000005: ## It is part of the source code for the Lunar Module's (LM)
028024,000006: ## Apollo Guidance Computer (AGC), for Apollo 11.
028025,000007: ## Assembler: yaYUL
028026,000008: ## Contact: Ron Burkey <info@sandroid.org>.
028027,000009: ## Website: www.ibiblio.org/apollo.
028028,000010: ## Pages: 654-657
028029,000011: ## Mod history: 2009-05-18 RSB Adapted from the corresponding
028030,000012: ## Luminary131 file, using page
028031,000013: ## images from Luminary 1A.
028032,000014: ##
028033,000015: ## This source code has been transcribed or otherwise adapted from
028034,000016: ## digitized images of a hardcopy from the MIT Museum. The digitization
028035,000017: ## was performed by Paul Fjeld, and arranged for by Deborah Douglas of
028036,000018: ## the Museum. Many thanks to both. The images (with suitable reduction
028037,000019: ## in storage size and consequent reduction in image quality as well) are
028038,000020: ## available online at www.ibiblio.org/apollo. If for some reason you
028039,000021: ## find that the images are illegible, contact me at info@sandroid.org
028040,000022: ## about getting access to the (much) higher-quality images which Paul
028041,000023: ## actually created.
028042,000024: ##
028043,000025: ## Notations on the hardcopy document read, in part:
028044,000026: ##
028045,000027: ## Assemble revision 001 of AGC program LMY99 by NASA 2021112-61
028046,000028: ## 16:27 JULY 14, 1969
028047,000029:
![]() |
Page 654 |
028049,000031: # GROUND TRACKING DETERMINATION PROGRAM -- P21
028050,000032: # PROGRAM DESCRIPTION
028051,000033: # MOD NO -- 1
028052,000034: # MOD BY -- N. M. NEVILLE
028053,000035:
028054,000036: # FUNCTIONAL DESCRIPTION --
028055,000037: # TO PROVIDE THE ASTRONAUT DETAILS OF THE LM OR CSM GROUND TRACK WITHOUT
028056,000038: # THE NEED FOR GROUND COMMUNICATION (REQUESTED BY DSKY).
028057,000039:
028058,000040: # CALLING SEQUENCE --
028059,000041: # ASTRONAUT REQUEST THROUGH DSKY V37E21E
028060,000042:
028061,000043: # SUBROUTINES CALLED --
028062,000044: # GOPERF4
028063,000045: # GOFLASH
028064,000046: # THISPREC
028065,000047: # OTHPREC
028066,000048: # LAT-LONG
028067,000049:
028068,000050: # NORMAL EXIT MODES --
028069,000051: # ASTRONAUT REQUEST THROUGH DSKY TO TERMINATE PROGRAM V34E
028070,000052:
028071,000053: # ALARM OR ABORT EXIT MODES --
028072,000054: # NONE
028073,000055:
028074,000056: # OUTPUT --
028075,000057: # OCTAL DISPLAY OF OPTION CODE AND VEHICLE WHOSE GROUND TRACK IS TO BE
028076,000058: # COMPUTED
028077,000059: # OPTION CODE 00002
028078,000060: # THIS 00001
028079,000061: # OTHER 00002
028080,000062: # DECIMAL DISPLAY OF TIME TO BE INTEGRATED TO HOURS, MINUTES, SECONDS
028081,000063: # DECIMAL DISPLAY OF LAT,LONG,ALT
028082,000064:
028083,000065: # ERASABLE INITIALIZATION REQUIRED
028084,000066: # AX0 2DEC 4.652459653 E-5 RADIANS $68-69 CONSTANTS*
028085,000067: # -AY0 2DEC 2.137535898 E-5 RADIANS
028086,000068: # AZ0 2DEC .7753206164 REVOLUTIONS
028087,000069: # FOR LUNAR ORBITS 504LM VECTOR IS NEEDED:
028088,000070: # 504LM 2DEC -2.700340600 E-5 RADIANS
028089,000071: # 504LM _2 2DEC -7.514128400 E-4 RADIANS
028090,000072: # 504LM _4 2DEC _2.553198641 E-4 RADIANS
028091,000073:
028092,000074: # NONE
028093,000075:
028094,000076: # DEBRIS
![]() |
Page 655 |
028096,000078: # CENTRALS -- A,Q,L
028097,000079: # OTHER -- THOSE USED BY THE ABOVE LISTED SUBROUTINES
028098,000080: # SEE LEMPREC, LAT-LONG
028099,000081:
028100,000082: 35,2545 30,2000 SBANK= LOWSUPER # FOR LOW 2CADR'S.
028101,000083:
028102,000084: 33,2200 BANK 33
028103,000085: 24,2000 SETLOC P20S
028104,000086: 24,2000 BANK
028105,000087:
028106,000088: 24,3505 E7,1762 EBANK= P21TIME
028107,000089: 24,3505 COUNT* $$/P21
028108,000090: 24,3505 34753 PROG21 CAF ONE
028109,000091: 24,3506 55145 TS OPTION2 # ASSUMED VEHICLE IS LM, R2 = 00001
028110,000092: 24,3507 34752 CAF BIT2 # OPTION 2
028111,000093: 24,3510 04616 TC BANKCALL
028112,000094: 24,3511 20633 CADR GOPERF4
028113,000095: 24,3512 06001 TC GOTOP00H # TERMINATE
028114,000096: 24,3513 03515 TC +2 # PROCEED VALUE OF ASSUMED VEHICLE OK
028115,000097: 24,3514 03507 TC -5 # R2 LOADED THROUGH DSKY
028116,000098: 24,3515 33665 P21PROG1 CAF V6N34 # LOAD DESIRED TIME OF LAT-LONG.
028117,000099: 24,3516 04616 TC BANKCALL
028118,000100: 24,3517 20476 CADR GOFLASH
028119,000101: 24,3520 06001 TC GOTOP00H # TERM
028120,000102: 24,3521 03523 TC +2 # PROCEED VALUES OK
028121,000103: 24,3522 03515 TC -5 # TIME LOADED THROUGH DSKY
028122,000104: 24,3523 06037 TC INTPRET
028123,000105: 24,3524 77745 DLOAD
028124,000106: 24,3525 01046 DSPTEM1
028125,000107: 24,3526 34041 STCALL TDEC1 # INTEG TO TIME SPECIFIED IN TDEC
028126,000108: 24,3527 27414 INTSTALL
028127,000109: 24,3530 43014 BON CLEAR
028128,000110: 24,3531 00304 P21FLAG
028129,000111: 24,3532 51550 P21CONT # ON -- RECYCLE USING BASE VECTOR
028130,000112: 24,3533 01674 VINTFLAG # OFF -- 1ST PASS CALL BASE VECTOR
028131,000113: 24,3534 70535 SLOAD SR1
028132,000114: 24,3535 01146 OPTION2
028133,000115: 24,3536 43030 BHIZ SET
028134,000116: 24,3537 51541 +2 # ZERO -- THIS VEHICLE (LM)
028135,000117: 24,3540 01474 VINTFLAG # ONE -- OTHER VEHICLE (CM)
028136,000118: 24,3541 43014 CLEAR CLEAR
028137,000119: 24,3542 01676 DIM0FLAG
028138,000120: 24,3543 01673 INTYPFLG # PRECISION
028139,000121: 24,3544 77624 CALL
028140,000122: 24,3545 27134 INTEGRV # CALCULATE
028141,000123: 24,3546 77650 GOTO # AND
028142,000124: 24,3547 51571 P21VSAVE # SAVE BASE VECTOR
028143,000125: 24,3550 77775 P21CONT VLOAD
028144,000126: 24,3551 03676 P21BASER # RECYCLE -- INTEG FROM BASE VECTOR
028145,000127: 24,3552 25535 STOVL RCV # --POS
![]() |
Page 656 |
028147,000129: 24,3553 03704 P21BASEV
028148,000130: 24,3554 15543 STODL VCV # --VEL
028149,000131: 24,3555 03763 P21TIME
028150,000132: 24,3556 01517 STORE TET # --TIME
028151,000133: 24,3557 43014 CLEAR CLEAR
028152,000134: 24,3560 01676 DIM0FLAG
028153,000135: 24,3561 00263 MOONFLAG
028154,000136: 24,3562 53135 SLOAD BZE
028155,000137: 24,3563 01164 P21ORIG
028156,000138: 24,3564 51567 +3 # ZERO = EARTH
028157,000139: 24,3565 77614 SET # ---2 = MOON
028158,000140: 24,3566 00063 MOONFLAG
028159,000141: 24,3567 77624 +3 CALL
028160,000142: 24,3570 27107 INTEGRVS
028161,000143: 24,3571 77745 P21VSAVE DLOAD # SAVE CURRENT BASE VECTOR
028162,000144: 24,3572 00015 TAT
028163,000145: 24,3573 27763 STOVL P21TIME # --TIME
028164,000146: 24,3574 00017 RATT1
028165,000147: 24,3575 27676 STOVL P21BASER # --POS B-29 OR B-27
028166,000148: 24,3576 00025 VATT1
028167,000149: 24,3577 03704 STORE P21BASEV # --VEL B-07 OR B-05
028168,000150: 24,3600 53646 ABVAL SL*
028169,000151: 24,3601 57576 0,2
028170,000152: 24,3602 27712 STOVL P21VEL # VEL/ FOR N91 DISP
028171,000153: 24,3603 00001 RATT
028172,000154: 24,3604 50256 UNIT DOT
028173,000155: 24,3605 00007 VATT # U(R).V
028174,000156: 24,3606 67471 DDV ASIN # U(R).U(V)
028175,000157: 24,3607 03712 P21VEL
028176,000158: 24,3610 03714 STORE P21GAM # SIN-1 U(R).U(V) , -90 TO +90
028177,000159: 24,3611 67334 SXA,2 SLOAD
028178,000160: 24,3612 01163 P21ORIG # 0 = EARTH
028179,000161: 24,3613 01146 OPTION2
028180,000162: 24,3614 46142 SR1 BHIZ
028181,000163: 24,3615 51620 +3
028182,000164: 24,3616 77650 GOTO
028183,000165: 24,3617 51623 +4
028184,000166: 24,3620 77614 +3 BON
028185,000167: 24,3621 04307 SURFFLAG
028186,000168: 24,3622 51625 P21DSP
028187,000169: 24,3623 77614 +4 SET
028188,000170: 24,3624 00064 P21FLAG
028189,000171: 24,3625 67214 P21DSP CLEAR SLOAD # GENERATE DISPLAY DATA
028190,000172: 24,3626 01663 LUNAFLAG
028191,000173: 24,3627 00050 X2
028192,000174: 24,3630 43054 BZE SET
028193,000175: 24,3631 51633 +2 # 0 = EARTH
028194,000176: 24,3632 01463 LUNAFLAG
028195,000177: 24,3633 77775 VLOAD
028196,000178: 24,3634 00001 RATT
![]() |
Page 657 |
028198,000180: 24,3635 16032 STODL ALPHAV
028199,000181: 24,3636 00015 TAT
028200,000182: 24,3637 45014 CLEAR CALL
028201,000183: 24,3640 00662 ERADFLAG
028202,000184: 24,3641 26351 LAT-LONG
028203,000185: 24,3642 77605 DMP # MPAC = ALT, METERS B-29
028204,000186: 24,3643 11667 K.01
028205,000187: 24,3644 03716 STORE P21ALT # ALT/100 FOR N91 DISP
028206,000188: 24,3645 77776 EXIT
028207,000189: 24,3646 33664 CAF V06N43 # DISPLAY LAT, LONG, ALT
028208,000190: 24,3647 04616 TC BANKCALL # LAT, LONG = 1/2 REVS B0
028209,000191: 24,3650 20476 CADR GOFLASH # ALT = KM B14
028210,000192: 24,3651 06001 TC GOTOP00H # TERM
028211,000193: 24,3652 06001 TC GOTOP00H
028212,000194: 24,3653 06037 TC INTPRET # V32E RECYCLE
028213,000195: 24,3654 43345 DLOAD DAD
028214,000196: 24,3655 03763 P21TIME
028215,000197: 24,3656 11663 600SEC # 600 SECONDS OR 10 MIN
028216,000198: 24,3657 01046 STORE DSPTEM1
028217,000199: 24,3660 77634 RTB
028218,000200: 24,3661 51515 P21PROG1
028219,000201: 24,3662 00003 25140 600SEC 2DEC 60000 B-28 # 10 MIN
028220,000202:
028221,000203: 24,3664 01453 V06N43 VN 00643
028222,000204: 24,3665 01442 V6N34 VN 00634
028223,000205: 24,3666 00243 32703 K.01 2DEC .01
028224,000206:
End of include-file GROUND_TRACKING_DETERMINATION_PROGRAM.agc. Parent file is MAIN.agc