Source Code
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This is a reconstructed version of Luminary 130, the initial AGC program released
in November 1969 for the Apollo 13 LM. Three more releases
followed before the flown revision was finally manufactured in February 1970.
This reconstruction was created from a previous transcription of the original listing of
Luminary 131, combined with Luminary memo #129 which describes the small difference
between the Luminary 130 and 131. The reconstructed source code was verified by
matching memory-bank checksums to those listed for Luminary 130 in drawing 2021152G.
In this source code, program comments from the original (Luminary 131) code are
prefixed with '#', while those added later by the Virtual AGC project are prefixed
with '##'.
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015277,000002: ## Copyright: Public domain.
015278,000003: ## Filename: GIMBAL_LOCK_AVOIDANCE.agc
015279,000004: ## Purpose: A section of the reconstructed source code for Luminary 130.
015280,000005: ## This was the original program released for the Apollo 13 LM,
015281,000006: ## although several more revisions would follow. It has been
015282,000007: ## reconstructed from a listing of Luminary 131, from which it
015283,000008: ## differs on only two lines in P70-P71. The difference is
015284,000009: ## described in detail in Luminary memo #129, which was used
015285,000010: ## to perform the reconstruction. This file is intended to be a
015286,000011: ## faithful reconstruction, except that the code format has been
015287,000012: ## changed to conform to the requirements of the yaYUL assembler
015288,000013: ## rather than the original YUL assembler.
015289,000014: ## Reference: p. 366
015290,000015: ## Contact: Ron Burkey <info@sandroid.org>.
015291,000016: ## Website: www.ibiblio.org/apollo/index.html
015292,000017: ## Mod history: 05/11/03 RSB. Began transcribing.
015293,000018: ## 05/14/05 RSB Corrected website reference above.
015294,000019: ## 2017-01-06 RSB Page numbers now agree with those on the
015295,000020: ## original harcopy, as opposed to the PDF page
015296,000021: ## numbers in 1701.pdf.
015297,000022: ## 2017-02-23 RSB Proofed comment text using octopus/ProoferComments.
015298,000023: ## 2017-08-22 RSB Fixed comment-text typo identified in ZERLINA 56.
015299,000024: ## 2018-09-04 MAS Copied from Luminary 131 for Luminary 130.
015300,000025:
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Page 366
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015302,000027: 15,2050 BANK 15
015303,000028:
015304,000029: 22,2000 SETLOC KALCMON1
015305,000030: 22,2000 BANK
015306,000031:
015307,000032: # DETECTING GIMBAL LOCK
015308,000033: 22,2744 22,2744 LOCSKIRT EQUALS NOGIMLOC
015309,000034:
015310,000035: 22,2744 77614 NOGIMLOC SET
015311,000036: 22,2745 01074 CALCMAN3
015312,000037: 22,2746 70740 WCALC LXC,1 DLOAD*
015313,000038: 22,2747 01322 RATEINDX # CHOOSE THE DESIRED MANEUVER RATE
015314,000039: 22,2750 04772 ARATE,1 # FROM A LIST OF FOUR
015315,000040: 22,2751 45002 SR4 CALL # COMPUTE THE INCREMENTAL ROTATION MATRIX
015316,000041: 22,2752 44527 DELCOMP # DEL CORRESPONDING TO A 1 SEC ROTATION
015317,000042: # ABOUT COF
015318,000043: 22,2753 74343 DLOAD* VXSC
015319,000044: 22,2754 04772 ARATE,1
015320,000045: 22,2755 03270 COF
015321,000046: 22,2756 17325 STODL BRATE # COMPONENT MANEUVER RATES 45 DEG/SEC
015322,000047: 22,2757 03335 AM
015323,000048: 22,2760 55605 DMP DDV*
015324,000049: 22,2761 05002 ANGLTIME
015325,000050: 22,2762 04772 ARATE,1
015326,000051: 22,2763 77661 SR
015327,000052: 22,2764 20606 5
015328,000053: 22,2765 03333 STORE TM # MANEUVER EXECUTION TIME SCALED AS T2
015329,000054: 22,2766 77614 SETGO
015330,000055: 22,2767 01035 CALCMAN2 # 0(OFF) = CONTINUE MANEUVER
015331,000056: 22,2770 45010 NEWANGL +1 # 1(ON) = START MANEUVER
015332,000057:
015333,000058: # THE FOUR SELECTABLE FREE FALL MANEUVER RATES SELECTED BY
015334,000059: # LOADING RATEINDX WITH 0, 2, 4, 6, RESPECTIVELY
015335,000060:
015336,000061: 22,2771 00221 24255 ARATE 2DEC .0088888888 # = 0.2 DEG/SEC $ 22.5 DEG/SEC
015337,000062: 22,2773 00554 02660 2DEC .0222222222 # = 0.5 DEG/SEC $ 22.5 DEG/SEC
015338,000063: 22,2775 02660 13301 2DEC .0888888888 # = 2.0 DEG/SEC $ 22.5 DEG/SEC
015339,000064: 22,2777 16161 30707 2DEC .4444444444 # = 10.0 DEG/SEC $ 22.5 DEG/SEC
015340,000065:
015341,000066: 22,3001 00003 04000 ANGLTIME 2DEC .0001907349 # = 100B-19 FUDGE FACTOR TO CONVERT
015342,000067: # MANEUVER ANGLE TO MANEUVER TIME
015343,000068:
015344,000069:
End of include-file GIMBAL_LOCK_AVOIDANCE.agc. Parent file is MAIN.agc