Pre-launch Review
ENTRY LEXICON
It name and Comanche 055 page images
# Copyright: Public domain.# Filename: ENTRY_LEXICON.agc# Purpose: Part of the source code for Comanche, build 055. It# is part of the source code for the Command Module's# (CM) Apollo Guidance Computer (AGC), Apollo 11.# Assembler: yaYUL# Reference: pp. 837-843# Contact: Ron Burkey <info@sandroid.org># Website: http://www.ibiblio.org/apollo.# Mod history: 2009-05-12 RSB Adapted from Colossus249 file of the same# name and Comanche 055 page images.## The contents of the "Comanche055" files, in general, are transcribed# from scanned documents.## Assemble revision 055 of AGC program Comanche by NASA# 2021113-051. April 1, 1969.## This AGC program shall also be referred to as Colossus 2A## Prepared by# Massachusetts Institute of Technology# 75 Cambridge Parkway# Cambridge, Massachusetts## under NASA contract NAS 9-4065.## Refer directly to the online document mentioned above for further# information. Please report any errors to info@sandroid.org.
# Page 837# VARIABLE DESCRIPTION MAXIMUM VALUE * COMPUTER NAME# -------- ----------- ------- ------- -------- ----## _# URT0 INITIAL TARGET VECTOR 2 (UNIT VECTOR) = RTINIT# _# UZ UNIT VECTOR NORTH 1 = UNITW# _# V VELOCITY VECTOR 2 VSAT = VEL# _# R POSITION VECTOR 2 EXP 29 METERS = RN# _# VI INERTIAL VELOCITY 128 M/CENTISEC = VN# _# RTE VECTOR EAST AT INITIAL TARGET 2 = RTEAST# _# UTR NORMAL TO RTE AND UZ 2 = RTNORM# _# URT TARGET VECTOR 2 = RT# _# UNI UNIT NORMAL TO TRAJECTORY PLANE 2# _# DELV INTEGRATED ACCEL. FROM PIPAS 5.85 16384 CM/S# _# G GRAVITY VECTOR 128 M/CENTISEC = GDT/2## A0 INITIAL DRAG FOR UPCONTRL 805 FPSS FPSS=FT/SEC/SEC# AHOOKDV TERM IN GAMMAL CALC. = AHOOK DVL 16# A1 DRAG VALUE IN FACTOR CALCULATION 805 FPSS# ALP CONST FOR UPCONTRL 1# ASKEP KEPLER RANGE 21600 NM NM = NAUTICAL MILE# ASP1 FINAL PHASE RANGE 21600 NM# ASPUP UP-RANGE 21600 NM# ASP3 GAMMA CORRECTION 21600 NM# ASPDWN RANGE DOWN TO PULL-UP 21600 NM# ASP PREDICTED RANGE 21600 NM NOT STORED# COSG COSINE(GAMMAL) 2 = COSG/2# C/D0 RECIPROCAL DRAG, -4/D0 B-8 64/FPSS# D TOTAL ACCELERATION 805 FPSS# D0 CONTROLLED CONSTANT D 805 FPSS# DHOOK TERM IN GAMMAL COMPUTATION 805 FPSS# DIFF THETNM-ASP (RANGE DIFFERENCE) 21600 NM# DIFFOLD PREVIOUS VALUE OF DIFF 21600 NM# DLEWD CHANGE IN LEWD 1# DR REFERENCE DRAG FOR DOWNCONTROL 805 FPSS NOT STORED# DREFR REFERENCE DRAG 805 FPSS NOT STORED# DVL VS1-VL 2 VSAT# E ECCENTRICITY 4 NOT STORED# F1 DRANGE/D DRAG (FINAL PHASE) 2700/805 = FX +5# F2 DRANGE/D RDOT (FINAL PHASE) 2700/2VS NM/FPS = FX +4# Page 838# F3 DRANGE/D (L/D) 2700 NM = FX# FACT1 CONST FOR UPCONTRL 805 FPSS# FACT2 CONST FOR UPCONTRL 1/805 FPSS# FACTOR USED IN UPCONTRL 1 * MAXIMUM VALUE DENOTES UNSCALED# GAMMAL FLIGHT PATH ANGLE AT VL 1 RADIAN VARIABLE VALUE WHEN SCALED# GAMMAL1 SIMPLE FORM OF GAMMAL 1 RADIAN VARIABLE HAS MAXIMUM VALUE OF ONE.# Page 839## HEADSUP INDICATOR FOR INITIAL ROLL 1# KA DRAG TO LIFT UP IF DOWN 805 FPSS = KAT# KLAT LATERAL SWITCH GAIN 1 (NOM = .0125)# K2ROLL INDICATOR FOR ROLL SWITCH# LAD MAX L/D (MIN ACTUAL VEHICLE L/D) 1# LADPAD NOMINAL VEHICLE L/D, SP PAD LOAD 1 (NOM = 0.3)# LATANG LATERAL RANGE 4 RADIANS# LEQ EXCESS C.F. OVER GRAV=(VSQ-1)GS 128.8 FPSS# LEWD UPCONTROL REFERENCE L/D 1# LOD FINAL PHASE L/D 1 (NOM = 0.18)# LODPAD FINAL PHASE L/D, SP PAD LOAD 1# L/D DESIRED LIFT TO DRAG RATIO 1# (VERTICAL PLANE)# L/D1 TEMP STORAGE FOR L/D IN LATERAL 1# L/DCMINR LAD COS(15DEG) 1 (NOM = 0.2895)# PREDANGL PREDICTED RANGE (FINAL PHASE) 2700 NM = PREDANG# Q2 FINAL PHASE RANGE -23500 Q3 21600 NM# Q2 = FCN(LAD)# Q7 MINIMUM DRAG FOR UPCONTROL 805 FPSS# RDOT ALTITUDE RATE 2 VSAT# RDOTREF REFERENCE RDOT FOR UPCONTROL 2 VSAT# RDTR REFERENCE RDOT FOR DOWNCONT 2 VSAT NOT SAVED# ROLLC ROLL COMMAND 1 REVOLUTION# RTOGO RANGE TO GO (FINAL PHASE) 2700 NM = FX +2# SL SINE OF LATITUDE 1 NOT SAVED# T TIME B 28 CENTISEC = TIME2,TIME1# THETA DESIRED RANGE (RADIANS) 2 PI RADIANS = THETAH# THETNM DESIRED RANGE (NM) 21600 NM NON EXISTENT# V VELOCITY MAGNITUDE 2 VSAT# V1 INITIAL VELOCITY FOR UPCONTROL 2 VSAT# VL EXIT VELOCITY FOR UPCONTROL 2 VSAT# VREF REFERENCE VELOCITY FOR UPCONTROL 2 VSAT# VS1 VSAT OR V1, WHICHEVER IS SMALLER 2 VSAT# 2 2# VBARS VL /VSAT 4# 2 2# VSQ NORMALISED VEL. SQUARED = V /VSAT 4 = VSQUARE# WT EARTH RATE TIMES TIME 1 REVOLUTION NOT SAVED# = WIE (DTEAROT)# X INTERMEDIATE VARIABLE IN G-LIMITER 2 VSAT NOT SAVED# Y LATERAL MISS LIMIT 4 RADIANS NOT SAVED
# Page 840# EXTRA COMPUTER ERASABLE LOCATIONS NOT SHOWN ON FLOW CHARTS# ----------------------------------------------------------## VARIABLE DESCRIPTION MAXIMUM VALUE# -------- ----------- -------------## GOTOADDR ADDRESS SELECTED BY SEQUENCER# XPIPBUF BUFFER TO STORE X PIPA COUNTS# YPIPBUF BUFFER TO STORE Y PIPA COUNTS# ZPIPBUF BUFFER TO STORE Z PIPA COUNTS# PIPCTR COUNTS PASSES THRU PIPA READ ROUTINE# JJ INDEX IN FINAL PHASE TABLE LOOK-UP# MM INDEX IN FINAL PHASE TABLE LOOK-UP# GRAD INTERPOLATION FACTOR IN FINAL PHASE# FX DRANGE/D L/D = F3 2700 NM# FX +1 AREF 805 FPSS# FX +2 RTOGO 2700 NM# FX +3 RDOTREF VSAT/4# FX +4 DRANGE/D RDOT = F2 21600/2VS NM/FPS# FX +5 DRANGE/D DRAG = F1 2700/805 NM/FPSS# TEM1B TEMPORARY LOCATION# TIME/RTO TIME OF INITIAL TARGET RTINIT B 28 CENTISEC# DTEAROT EST TIME BETWEEN RTINIT AND RT B 28 CENTISEC## _# UNITV UNIT V VECTOR 2# _# UNITR UNIT R VECTOR 2# _# -VREL NEGATIVE VELOCITY REL TO ATMOSP 2 VSAT## COMPUTER SWITCHES INITIAL STATE CM/FLAGS = STATE +6# ----------------- ------------- -------------------## ENTRYDSP DO ENTRY DISPLAY, IF SET NON-BRANCH (1) 92D, BIT13# GONEPAST INDICATES OVERSHOOT OF TARGET NON-BRANCH (0) 95D, BIT10# RELVELSW RELATIVE VELOCITY SWITCH NON-BRANCH (0) 96D, BIT 9# EGSW FINAL PHASE SWITCH NON-BRANCH (0) 97D, BIT 8# FIRSTPAS INITIAL PASS THRU HUNTEST NON-BRANCH (0) 98D, BIT 7# HIND INDICATES ITERATION IN HUNTEST NON-BRANCH (0) 99D, BIT 6# INRLSW INDICATES INIT ROLL ATTITUDE SET NON-BRANCH (0) 100D, BIT 5# LATSW INHIBIT DOWNLIFT SWITCH IF NOT SET BRANCH (1) 101D, BIT 4# .05GSW INDICATES DRAG EXCEEDS .05 GS BRANCH (0) 102D, BIT 3## GONEBY INDICATES GONE PAST TARGET (SET) SELF-INITIALIZING 112D, BIT 8
# Page 841# CONSTANTS AND GAINS VALUE# ------------------- -----## C1 FACTOR IN ALP COMPUTATION 1.25# C16 CONSTD GAIN ON DRAG .01# C17 CONSTD GAIN ON RDOT .001# C18 BIAS VEL. FOR FINAL PHASE START 500 FPS# C20 MAX DRAG FOR DOWN-LIFT 175 FPSS# CHOOK FACTOR IN AHOOK COMPUTATION .25# CH1 FACTOR IN GAMMAL COMPUTATION 1.0# COS15 COS( 15 DEG) .965# DLEWD0 INITIAL VARIATION IN LEWD -.05# D2 DRAG TO CHANGE LEWD 175 FPSS# DT COMPUTATION CYCLE TIME INTERVAL 2 SEC.# GMAX MAXIMUM ACCELERATION 257.6 FPSS (8 G-S)# KA1 FACTOR IN KA CALC 1.3 GS# KA2 FACTOR IN KA CALC .2 GS# KA3 FACTOR IN D0 CALC 90 FPSS# KA4 FACTOR IN D0 CALC 40 FPSS# KB1 OPTIMIZED UPCONTROL GAIN 3.4# KB2 OPTIMIZED UPCONTROL GAIN .0034# KDMIN INCREMENT ON Q7 TO DETECT END OF KEPLER PHASE .5 FPSS# KTETA TIME OF FLIGHT CONSTANT 1000# KLAT1 FACTOR IN KLAT CALC 1/24# K44 GAIN USED IN INITIAL ROLL SECTION 19749550 FPS# LATBIAS LATERAL SWITCH BIAS TERM .41252961 NM# LEWD1 NOMINAL UPCONTROL L/D .15# POINT1 FACTOR TO REDUCE UPCONTROL GAIN .1# Q2 FINAL PHASE RANGE - 23500 Q3 -1002 NM# Q3 FINAL PHASE DRANGE/D V .07 NM/FPS# Q5 FINAL PHASE DRANGE/D GAMMA 7050 NM/RAD# Q6 FINAL PHASE INITIAL FLIGHT PATH ANGLE .0349 RAD# Q7F MIN DRAG FOR UPCONTROL 6 FPSS# Q7MIN MIN VALUE FOR Q7 IN FACTOR CALCULATION 40 FPSS# Q19 FACTOR IN GAMMAL1 CALCULATION .5# Q21 FACTOR IN Q2 CALCULATION. 1000 NM# Q22 FACTOR IN Q2 CALCULATION. -1302 NM# VFINAL1 VELOCITY TO START FINAL PHASE ON INITIAL ENTRY 27000 FPS# VFINAL FACTOR IN INITIAL UP-DOWN CALC 26600 FPS# VLMIN MINIMUM VL 18000 FPS# VMIN VELOCITY TO SWITCH TO RELATIVE VEL VSAT/2# VRCONTRL RDOT TO START INTO HUNTEST 700 FPS# VRCONT = COMPUTER NAME# 25NM TOLERANCE TO STOP RANGE ITERATION 25 NM# VQUIT VELOCITY TO STOP STEERING 1000 FPS
# Page 842# CONVERSION FACTORS AND SCALING CONSTANTS# ---------- ------- --- ------- ---------## ATK ANGLE IN RAD TO NM 3437.7468 NM/RAD# G5 NOMINAL G VALUE FOR SCALING 32.2 FPSS# H5 ATMOSPHERE SCALE HEIGHT 28500 FT# J GRAVITY HARMONIC COEFFICIENT .00162346# KWE EQUATORIAL EARTH RATE 1546.70168 FPS# MUE EARTH GRAVITATIONAL CONSTANT 3.986032233 E 14 CUBIC M/ SEC SEC# RE EARTH RADIUS 21202900 FT# REQ EARTH EQUATORIAL RADIUS 20925738.2 FT# VSAT SATELLITE VELOCITY AT RE 25766.1973 FPS# WIE EARTH RATE .0000729211505 RAD/SEC## (END GSOP AS-278, VOL 1, FIG. 5.6-3 CONSTANTS,GAINS, ETC.)### DISPLAY QUANTITIES# ------------------## (SEE SECTION 4 OF THE GSOP FOR SIGN CONVENTIONS.)## VARIABLE DESCRIPTION MAXIMUM VALUE# -------- ----------- -------------## GMAX PREDICTED MAXIMUM ENTRY ACCEL 163.84 GS N 60# VPRED PREDICTED VELOCITY AT ALTITUDE 128 M/CENTISEC N 60# 400K FT ABOVE FISCHER RADIUS.# GAMMAEI PREDICTED GAMMA AT ALTITUDE 1 REVOLUTION N 60# 400K FT ABOVE FISCHER RADIUS.# D DRAG ACCELERATION 805 FPSS N 64# VMAGI INERTIAL VELOCITY MAGNITUDE 128 M/CENTISEC N 64, N 68# THETAH DESIRED RANGE ANGLE NM 1 REVOLUTION N 64, N 67# LAT PRESENT LATITUDE 1 REVOLUTION N 67# LONG PRESENT LONGITUDE 1 REVOLUTION N 67# RTOGO RANGE ANGLE TO SPLASH FROM 1 REVOLUTION N 63# EMSALT FT ABOVE FISCHER RADIUS. (IN NM)# VIO PREDICTED VELOCITY AT ALTITUDE 128 M/CENTISEC N 63# EMSALT FT ABOVE FISCHER RADIUS.# TTE TIME OF FREE FALL TO ALT B 28 CENTISEC N 63# EMSALT FT ABOVE FISCHER RADIUS.# ROLLC ROLL COMMAND 1 REVOLUTION N 66, N 68, N 69# LATANG CROSS-RANGE ERROR (XRNGERR) 4 RADIANS N 66# DNRNGERR DOWN RANGE ERROR 1 REVOLUTION N 66# (PREDANG - THETAH IN NM)# HDOT ALTITUDE RATE 128 M/CENTISEC N 68# Q7 MINIMUM DRAG FOR UPCONTROL 805 FPSS N 69# VL EXIT VELOCITY FOR UP-CONTROL 2 VSAT N 69
# Page 843# BODY ATTITUDE QUANTITIES (CM/POSE)# ----------------------------------## VARIABLE DESCRIPTION MAXIMUM VALUE# -------- ---------- ------- -----## _# -VREL NEGATIVE VELOCITY REL TO ATMOS. 2 VSAT# _# OLDUYA USED FOR UYA BELOW 1000 FPS 2# _# UXA/2 UNIT VECTOR TRIAD 2# _# UYA/2 BASED ON 2# _# UZA/2 THE TRAJECTORY. 2# _# UBX/2 UNIT VECTOR 2# _# UBY/2 BODY TRIAD 2# _# UBZ/2 FOR CM. 2