# Copyright: Public domain. # Filename: LAMBERT_AIMPOINT_GUIDANCE.agc # Purpose: Part of the source code for Luminary 1A build 099. # It is part of the source code for the Lunar Module's (LM) # Apollo Guidance Computer (AGC), for Apollo 11. # Assembler: yaYUL # Contact: Ron Burkey . # Website: www.ibiblio.org/apollo. # Pages: 651-653 # Mod history: 2009-05-18 RSB Transcribed from Luminary 099 # page images. # 2009-06-05 RSB Corrected 4 typos. # 2009-06-07 RSB Fixed a typo. # # This source code has been transcribed or otherwise adapted from # digitized images of a hardcopy from the MIT Museum. The digitization # was performed by Paul Fjeld, and arranged for by Deborah Douglas of # the Museum. Many thanks to both. The images (with suitable reduction # in storage size and consequent reduction in image quality as well) are # available online at www.ibiblio.org/apollo. If for some reason you # find that the images are illegible, contact me at info@sandroid.org # about getting access to the (much) higher-quality images which Paul # actually created. # # Notations on the hardcopy document read, in part: # # Assemble revision 001 of AGC program LMY99 by NASA 2021112-61 # 16:27 JULY 14, 1969 # Page 651 # GENERAL LAMBERT AIMPOINT GUIDANCE ** # WRITTEN BY RAMA M AIYAWAR # PROGRAM P-31 DESCRIPTION ** # # 1. TO ACCEPT TARGETING PARAMETERS OBTAINED FROM A SOURCE EXTERNAL # TO THE LEM AND COMPUTE THERE FROM THE REQUIRED-VELOCITY AND # OTHER INITIAL CONDITIONS REQUIRED BY LM FOR DESIRED MANEUVER. # THE TARGETING PARAMETERS ARE TIG (TIME OF IGNITION), TARGET # VECTOR (RTARG), AND THE TIME FROM TIG UNTIL THE TARGET IS # REACHED (DELLT4), DESIRED TIME OF FLIGHT FROM RINIT TO RTARG. # ASSUMPTIONS ** # # 1. THE TARGET PARAMETERS MAY HAVE BEEN LOADED PRIOR TO THE # EXECUTION OF THIS PROGRAM. # 2. THIS PROGRAM IS APPLICABLE IN EITHER EARTH OR LUNAR ORBIT. # 3. THIS PROGRAM IS DESIGNED FOR ONE-MAN OPERATION, AND SHOULD # BE SELECTED BY THE ASTRONAUT BY DSKY ENTRY V37 E31. # SUBROUTINES USED ** # # MANUPARM, TTG/N35, R02BOTH, MIDGIM, DISPMGA, FLAGDOWN, BANKCALL, # GOTOPOOH, ENDOFJOB, PHASCHNG, GOFLASHR, GOFLASH. # # MANUPARM CALCULATES APOGEE, PERIGEE ALTITUDES AND DELTAV DESIRED # FOR THE MANEUVER. # # TTG/N35 CLOCKTASK - UPDATES CLOCK. # # MIDGIM CALCULATES MIDDLE GIMBAL ANGLE FOR DISPLAY. # # R02BOTH IMU - STATUS CHECK ROUTINE. # DISPLAYS USED IN P-31LM ** # # V06N33 DISPLAY STORED TIG (IN HRS. MINS. SECS.) # V06N42 DISPLAY APOGEE, PERIGEE, DELTAV. # V16N35 DISPLAY TIME FROM TIG. # V06N45 TIME FROM IGNITION AND MIDDLE GIMBAL ANGLE. # ERASABLE INITIALIZATION REQUIRED ** # # TIG TIME OF IGNITION DP (B+28) CS. # # DELLT4 DESIRED TIME OF FLIGHT DP (B+28) CS # FROM RINIT TO RTARG. # # RTARG RADIUS VECTOR OF TARGET POSITION VECTOR # RADIUS VECTOR SCALED TO (B+29)METERS IF EARTH ORBIT # Page 652 # RADIUS VECTOR SCALED TO (B+27)METERS IF MOON ORBIT # OUTPUT ** # # HAPO APOGEE ALTITUDE # HPER PERIGEE ALTITUDE # VGDISP MAG. OF DELTAV FOR DISPLAY, SCALING B+7 M/CS EARTH # MAG. OF DELTAV FOR DISPLAY, SCALING B+5 M/CS MOON # MIDGIM MIDDLE GIMBAL ANGLE # XDELVFLG RESETS XDELVFLG FOR LAMBERT VG COMPUTATIONS # ALARMS OR ABORTS NONE ** # RESTARTS ARE VIA GROUP 4 ** SETLOC GLM BANK EBANK= SUBEXIT COUNT* $$/P31 P31 TC P20FLGON CAF V06N33 # T16 TC VNP00H TC INTPRET CLEAR DLOAD UPDATFLG TIG STCALL TDEC1 # INTEGRATE STATE VECTORS TO TIG LEMPREC VLOAD SETPD RATT 0D STORE RTIG STOVL RINIT VATT STORE VTIG STODL VINIT P30ZERO PUSH PDDL # E4 AND NUMIT = 0 DELLT4 DAD SXA,1 TIG RTX1 STORE TPASS4 SXA,2 CALL RTX2 INITVEL VLOAD PUSH # Page 653 DELVEET3 STORE DELVSIN ABVAL CLEAR XDELVFLG STCALL VGDISP GET.LVC VLOAD PDVL RTIG VIPRIME CALL PERIAPO1 CALL SHIFTR1 CALL # LIMIT DISPLAY TO 9999.9 N. MI. MAXCHK STODL HPER 4D CALL SHIFTR1 CALL # LIMIT DISPLAY TO 9999.9 N. MI. MAXCHK STORE HAPO EXIT CAF V06N81 # DELVLVC TC VNP00H CAF V06N42 # HAPO, HPER, VGDISP TC VNP00H TC INTPRET REVN1645 SET CALL # TRKMKCNT, TTOGO, +MGA FINALFLG VN1645 GOTO REVN1645 # *** END OF LEMP30S .103 ***