77 lines
2.2 KiB
Plaintext
77 lines
2.2 KiB
Plaintext
# Copyright: Public domain.
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# Filename: GIMBAL_LOCK_AVOIDANCE.agc
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# Purpose: Part of the source code for Luminary 1A build 099.
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# It is part of the source code for the Lunar Module's (LM)
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# Apollo Guidance Computer (AGC), for Apollo 11.
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# Assembler: yaYUL
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# Contact: Ron Burkey <info@sandroid.org>.
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# Website: www.ibiblio.org/apollo.
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# Pages: 364
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# Mod history: 2009-05-17 RSB Adapted from the corresponding
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# Luminary131 file, using page
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# images from Luminary 1A.
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# 2010-12-31 JL Fixed page number comment.
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#
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# This source code has been transcribed or otherwise adapted from
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# digitized images of a hardcopy from the MIT Museum. The digitization
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# was performed by Paul Fjeld, and arranged for by Deborah Douglas of
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# the Museum. Many thanks to both. The images (with suitable reduction
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# in storage size and consequent reduction in image quality as well) are
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# available online at www.ibiblio.org/apollo. If for some reason you
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# find that the images are illegible, contact me at info@sandroid.org
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# about getting access to the (much) higher-quality images which Paul
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# actually created.
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#
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# Notations on the hardcopy document read, in part:
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#
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# Assemble revision 001 of AGC program LMY99 by NASA 2021112-61
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# 16:27 JULY 14, 1969
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# Page 364
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BANK 15
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SETLOC KALCMON1
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BANK
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# DETECTING GIMBAL LOCK
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LOCSKIRT EQUALS NOGIMLOC
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NOGIMLOC SET
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CALCMAN3
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WCALC LXC,1 DLOAD*
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RATEINDX # CHOOSE THE DESIRED MANEUVER RATE
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ARATE,1 # FROM A LIST OF FOUR
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SR4 CALL # COMPUTE THE INCREMENTAL ROTATION MATRIX
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DELCOMP # DEL CORRESPONDING TO A 1 SEC ROTATION
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# ABOUT COF
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DLOAD* VXSC
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ARATE,1
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COF
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STODL BRATE # COMPONENT MANEUVER RATES 45 DEG/SEC
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AM
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DMP DDV*
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ANGLTIME
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ARATE,1
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SR
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5
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STORE TM # MANEUVER EXECUTION TIME SCALED AS T2
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SETGO
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CALCMAN2 # D(OFF) = CONTINUE MANEUVER
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NEWANGL +1 # 1(ON) = START MANEUVER
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# THE FOUR SELECTABLE FREE FALL MANEUVER RATES SELECTED BY
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# LOADING RATEINDX WITH 0, 2, 4, 6, RESPECTIVELY
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ARATE 2DEC .0088888888 # = 0.2 DEG/SEC $ 22.5 DEG/SEC
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2DEC .0222222222 # = 0.5 DEG/SEC $ 22.5 DEG/SEC
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2DEC .0888888888 # = 2.0 DEG/SEC $ 22.5 DEG/SEC
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2DEC .4444444444 # = 10.0 DEG/SEC $ 22.5 DEG/SEC
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ANGLTIME 2DEC .0001907349 # = 100B-19 FUDGE FACTOR TO CONVERT
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# MANEUVER ANGLE TO MANEUVER TIME
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