Source Code
034917,000001: # Copyright: Public domain.
034918,000002: # Filename: ENTRY_LEXICON.agc
034919,000003: # Purpose: Part of the source code for Colossus, build 249.
034920,000004: # It is part of the source code for the Command Module's (CM)
034921,000005: # Apollo Guidance Computer (AGC), possibly for Apollo 8 and 9.
034922,000006: # Assembler: yaYUL
034923,000007: # Reference: pp. 795-801 of 1701.pdf.
034924,000008: # Contact: Ron Burkey <info@sandroid.org>.
034925,000009: # Website: www.ibiblio.org/apollo.
034926,000010: # Mod history: 08/19/04 RSB. Transcribed .
034927,000011:
034928,000012: # The contents of the "Colossus249" files, in general, are transcribed
034929,000013: # from a scanned document obtained from MIT's website,
034930,000014: # http://hrst.mit.edu/hrs/apollo/public/archive/1701.pdf. Notations on this
034931,000015: # document read, in part:
034932,000016:
034933,000017: # Assemble revision 249 of AGC program Colossus by NASA
034934,000018: # 2021111-041. October 28, 1968.
034935,000019:
034936,000020: # This AGC program shall also be referred to as
034937,000021: # Colossus 1A
034938,000022:
034939,000023: # Prepared by
034940,000024: # Massachussets Institute of Technology
034941,000025: # 75 Cambridge Parkway
034942,000026: # Cambridge, Massachusetts
034943,000027: # under NASA contract NAS 9-4065.
034944,000028:
034945,000029: # Refer directly to the online document mentioned above for further information.
034946,000030: # Please report any errors (relative to 1701.pdf) to info@sandroid.org.
034947,000031:
034948,000032: # In some cases, where the source code for Luminary 131 overlaps that of
034949,000033: # Colossus 249, this code is instead copied from the corresponding Luminary 131
034950,000034: # source file, and then is proofed to incorporate any changes.
034951,000035:
034952,000036: # Page 795
034953,000037: # VARIABLE DESCRIPTION MAXIMUM VALUE * COMPUTER NAME
034954,000038: # -------- ----------- --------------- -------------
034955,000039: # _
034956,000040: # URT0 INITIAL TARGET VECTOR 2 (UNIT VECTOR) = RTINIT
034957,000041: # _
034958,000042: # UZ UNIT VECTOR NORTH 1 = UNITW
034959,000043: # _
034960,000044: # V VELOCITY VECTOR 2 VSAT = VEL
034961,000045: # _
034962,000046: # R POSITION VECTOR 2 EXP 29 METERS = RN
034963,000047: # _
034964,000048: # VI INERTIAL VELOCITY 128 M/CENTISEC = VN
034965,000049: # _
034966,000050: # RTE VECTOR EAST AT INITIAL TARGET 2 = RTEAST
034967,000051: # _
034968,000052: # UTR NORMAL TO RTE AND UZ 2 = RTNORM
034969,000053: # _
034970,000054: # URT TARGET VECTOR 2 = RT
034971,000055: # _
034972,000056: # UNI UNIT NORMAL TO TRAJECTORY PLANE 2
034973,000057: # _
034974,000058: # DELV INTEGRATED ACCEL. FROM PIPAS 5.85 16384 CM/S
034975,000059: # _
034976,000060: # G GRAVITY VECTOR 128 M/CENTISEC = GDT/2
034977,000061:
034978,000062: # A0 INITIAL DRAG FOR UPCONTRL 805 FPSS FPSS=FT/SEC/SEC
034979,000063:
034980,000064: # AHOOKDV TERM IN GAMMAL CALC. = AHOOK DVL 16
034981,000065:
034982,000066: # A1 DRAG VALUE IN FACTOR CALCULATION 805 FPSS
034983,000067:
034984,000068: # ALP CONST FOR UPCONTRL 1
034985,000069:
034986,000070: # ASKEP KEPLER RANGE 21600 NM NM = NAUTICAL MILE
034987,000071:
034988,000072: # ASP1 FINAL PHASE RANGE 21600 NM
034989,000073:
034990,000074: # ASPUP UP-RANGE 21600 NM
034991,000075:
034992,000076: # ASP3 GAMMA CORRECTION 21600 NM
034993,000077:
034994,000078: # ASPDWN RANGE DOWN TO PULL-UP 21600 NM
034995,000079:
034996,000080: # ASP PREDICTED RANGE 21600 NM NOT STORED
034997,000081:
034998,000082: # COSG COSINE(GAMMAL) 2 = COSG/2
034999,000083:
035000,000084: # C/D0 RECIPROCAL DRAG, -4/D0 B-8 64/FPSS
035001,000085:
035002,000086: # D TOTAL ACCELERATION 805 FPSS
035003,000087:
035004,000088: # D0 CONTROLLED CONSTANT D 805 FPSS
035005,000089:
035006,000090: # DHOOK TERM IN GAMMAL COMPUTATION 805 FPSS
035007,000091:
035008,000092: # DIFF THETNM-ASP (RANGE DIFFERENCE) 21600 NM
035009,000093:
035010,000094: # DIFFOLD PREVIOUS VALUE OF DIFF 21600 NM
035011,000095:
035012,000096: # DLEWD CHANGE IN LEWD 1
035013,000097:
035014,000098: # DR REFERENCE DRAG FOR DOWNCONTROL 805 FPSS NOT STORED
035015,000099:
035016,000100: # DREFR REFERENCE DRAG 805 FPSS NOT STORED
035017,000101:
035018,000102: # DVL VS1-VL 2 VSAT
035019,000103:
035020,000104: # E ECCENTRICITY 4 NOT STORED
035021,000105:
035022,000106: # F1 DRANGE/D DRAG (FINAL PHASE) 2700/805 = FX +5
035023,000107:
035024,000108: # F2 DRANGE/D RDOT (FINAL PHASE) 2700/2VS NM/FPS = FX +4
035025,000109: # Page 796
035026,000110:
035027,000111: # F3 DRANGE/D (L/D) 2700 NM = FX
035028,000112:
035029,000113: # FACT1 CONST FOR UPCONTRL 805 FPSS
035030,000114:
035031,000115: # FACT2 CONST FOR UPCONTRL 1/805 FPSS
035032,000116:
035033,000117: # FACTOR USED IN UPCONTRL 1 * MAXIMUM VALUE DENOTES UNSCALED
035034,000118: # VARIABLE VALUE WHEN SCALED
035035,000119: # GAMMAL FLIGHT PATH ANGLE AT VL 1 RADIAN VARIABLE HAS MAXIMUM VALUE OF ONE.
035036,000120:
035037,000121: # GAMMAL1 SIMPLE FORM OF GAMMAL 1 RADIAN
035038,000122: # Page 797
035039,000123:
035040,000124: # HEADSUP INDICATOR FOR INITIAL ROLL 1
035041,000125:
035042,000126: # KA DRAG TO LIFT UP IF DOWN 805 FPSS = KAT
035043,000127:
035044,000128: # KLAT LATERAL SWITCH GAIN 1 (NOM = .0125)
035045,000129:
035046,000130: # K2ROLL INDICATOR FOR ROLL SWITCH
035047,000131:
035048,000132: # LAD MAX L/D (MIN ACTUAL VEHICLE L/D) 1
035049,000133:
035050,000134: # LADPAD NOMINAL VEHICLE L/D, SP PAD LOAD 1 (NOM = 0.3)
035051,000135:
035052,000136: # LATANG LATERAL RANGE 4 RADIANS
035053,000137:
035054,000138: # LEQ EXCESS C.F. OVER GRAV=(VSQ-1)GS 128.8 FPSS
035055,000139:
035056,000140: # LEWD UPCONTROL REFERENCE L/D 1
035057,000141:
035058,000142: # LOD FINAL PHASE L/D 1 (NOM = 0.18)
035059,000143:
035060,000144: # LODPAD FINAL PHASE L/D, SP PAD LOAD 1
035061,000145:
035062,000146: # L/D DESIRED LIFT TO DRAG RATIO 1
035063,000147: # (VERTICAL PLANE)
035064,000148: #
035065,000149: # L/D1 TEMP STORAGE FOR L/D IN LATERAL 1
035066,000150:
035067,000151: # L/DCMINR LAD COS(15DEG) 1 (NOM = 0.2895)
035068,000152:
035069,000153: # PREDANGLE PREDICTED RANGE (FINAL PHASE) 2700 NM = PREDANG
035070,000154:
035071,000155: # Q2 FINAL PHASE RANGE -23500 Q3 21600 NM
035072,000156: # Q2 = FCN(LAD)
035073,000157:
035074,000158: # Q7 MINIMUM DRAG FOR UPCONTROL 805FPSS
035075,000159:
035076,000160: # RDOT ALTITUDE RATE 2 VSAT
035077,000161:
035078,000162: # RDOTREF REFERENCE RDOT FOR UPCONTROL 2 VSAT
035079,000163:
035080,000164: # RDTR REFERENCE RDOT FOR DOWNCONT 2 VSAT NOT SAVED
035081,000165:
035082,000166: # ROLLC ROLL COMMAND 1 REVOLUTION
035083,000167:
035084,000168: # RTOGO RANGE TO GO (FINAL PHASE) 2700 NM = FX +2
035085,000169:
035086,000170: # SL SINE OF LATITUDE 1 NOT SAVED
035087,000171:
035088,000172: # T TIME B 28 CENTISEC = TIME2,TIME1
035089,000173:
035090,000174: # THETA DESIRED RANGE (RADIANS) 2 PI RADIANS = THETAH
035091,000175:
035092,000176: # THETNM DESIRED RANGE (NM) 21600 NM NON EXISTENT
035093,000177:
035094,000178: # V VELOCITY MAGNITUDE 2 VSAT
035095,000179: #
035096,000180: # V1 INITIAL VELOCITY FOR UPCONTROL 2 VSAT
035097,000181:
035098,000182: # VL EXIT VELOCITY FOR UPCONTROL 2 VSAT
035099,000183:
035100,000184: # VREF REFERENCE VELOCITY FOR UPCONTROL 2 VSAT
035101,000185:
035102,000186: # VS1 VSAT OR V1, WHICHEVER IS SMALLER 2 VSAT
035103,000187: # 2 2
035104,000188: # VBARS VL /VSAT 4
035105,000189: # 2 2
035106,000190: # VSQ NORMALIZED VEL. SQUARED = V /VSAT 4 = VSQUARE
035107,000191:
035108,000192: # WT EARTH RATE TIMES TIME 1 REVOLUTION NOT SAVED
035109,000193:
035110,000194: # X INTERMEDIATE VARIABLE IN G-LIMITER 2 VSAT NOT SAVED
035111,000195:
035112,000196: # Y LATERAL MISS LIMIT 4 RADIANS NOT SAVED
035113,000197:
035114,000198: # Page 798
035115,000199: # EXTRA COMPUTER ERASABLE LOCATIONS NOT SHOWN ON FLOW CHARTS
035116,000200: # ----------------------------------------------------------
035117,000201:
035118,000202: # VARIABLE DESCRIPTION MAXIMUM VALUE
035119,000203: # -------- ----------- -------------
035120,000204:
035121,000205: # GOTOADDR ADDRESS SELECTED BY SEQUENCER
035122,000206:
035123,000207: # XPIPBUF BUFFER TO STORE X PIPA COUNTS
035124,000208:
035125,000209: # YPIPBUF BUFFER TO STORE Y PIPA COUNTS
035126,000210:
035127,000211: # ZPIPBUF BUFFER TO STORE Z PIPA COUNTS
035128,000212:
035129,000213: # PIPCTR COUNTS PASSES THRU PIPA READ ROUTINE
035130,000214:
035131,000215: # JJ INDEX IN FINAL PHASE TABLE LOOK-UP
035132,000216:
035133,000217: # MM INDEX IN FINAL PHASE TABLE LOOK-U
035134,000218:
035135,000219: # GRAD INTERPOLATION FACTOR IN FINAL PHASE
035136,000220:
035137,000221: # FX DRANGE/D L/D = F3 2700 NM
035138,000222:
035139,000223: # FX +1 AREF 805 FPSS
035140,000224:
035141,000225: # FX +2 RTOGO 2700 NM
035142,000226:
035143,000227: # FX +3 RDOTREF VSAT/4
035144,000228:
035145,000229: # FX +4 DRANGE/D RDOT = F2 21600/2VS NM/FPS
035146,000230:
035147,000231: # FX +5 DRANGE/D DRAG = F1 2700/805 NM/FPSS
035148,000232:
035149,000233: # TEM1B TEMPORARY LOCATION
035150,000234:
035151,000235: # TIME/RTO TIME OF INITIAL TARGET RTINIT B 28 CENTISEC
035152,000236:
035153,000237: # DTEAROT EST TIME BETWEEN RTINIT AND RT B 28 CENTISEC
035154,000238: # _
035155,000239: # UNITV UNIT V VECTOR 2
035156,000240: # _
035157,000241: # UNITR UNIT R VECTOR 2
035158,000242: # _
035159,000243: # -VREL NEGATIVE VELOCITY REL TO ATMOSP 2 VSAT
035160,000244:
035161,000245: # COMPUTER SWITCHES INITIAL STATE CM/FLAGS = STATE +6
035162,000246: # ----------------- ------------- -------------------
035163,000247:
035164,000248: # ENTRYDSP DO ENTRY DISPLAY, IF SET NON-BRANCH (1) 92D, BIT 13
035165,000249: # GONEPAST INDICATES OVERSHOOT OF TARGET NON-BRANCH (0) 95D, BIT 10
035166,000250: # RELVELSW RELATIVE VELOCITY SWITCH NON-BRANCH (0) 96D, BIT 9
035167,000251: # EGSW FINAL PHASE SWITCH NON-BRANCH (0) 97D, BIT 8
035168,000252: # FIRSTPAS INITIAL PASS THRU HUNTEST NON-BRANCH (0) 98D, BIT 7
035169,000253: # HIND INDICATES ITERATION IN HUNTEST NON-BRANCH (0) 99D, BIT 6
035170,000254: # INRLSW INDICATES INIT ROLL ATTITUDE SET NON-BRANCH (0) 100D, BIT 5
035171,000255: # LATSW INHIBIT DOWNLIFT SWITCH IF NOT SET BRANCH (1) 101D, BIT 4
035172,000256: # .05GSW INDICATES DRAG EXCEEDS .05 GS BRANCH (0) 102D, BIT 3
035173,000257:
035174,000258: # GONEBY INDICATES GONE PAST TARGET (SET) SELF-INITIALIZING 112D, BIT 6
035175,000259:
035176,000260: # Page 799
035177,000261: # CONSTANTS AND GAINS VALUE
035178,000262: # ------------------- -----
035179,000263:
035180,000264: # C1 FACTOR IN ALP COMPUTATION 1.25
035181,000265: # C16 CONSTD GAIN ON DRAG .01
035182,000266: # C17 CONSTD GAIN ON RDOT .001
035183,000267: # C18 BIAS VEL. FOR FINAL PHASE START 500 FPS
035184,000268: # C20 MAX DRAG FOR DOWN-LIFT 175 FPSS
035185,000269: # CHOOK FACTOR IN AHOOK COMPUTATION .25
035186,000270: # CH1 FACTOR IN GAMMAL COMPUTATION 1.0
035187,000271: # COS15 COS( 15 DEG ) .965
035188,000272: # DLEWD0 INITIAL VARIATION IN LEWD -.05
035189,000273: # D2 DRAG TO CHANGE LEWD 175 FPSS
035190,000274: # DT COMPUTATION CYCLE TIME INTERVAL 2 SEC.
035191,000275: # GMAX MAXIMUM ACCELERATION 257.6 FPSS (6 G-S)
035192,000276: # KA1 FACTOR IN KA CALC 1.3 GS
035193,000277: # KA2 FACTOR IN KA CALC .2 GS
035194,000278: # KA3 FACTOR IN D0 CALC 90 FPSS
035195,000279: # KA4 FACTOR IN D0 CALC 40 FPSS
035196,000280: # KB1 OPTIMIZED UPCONTROL GAIN 3.4
035197,000281: # KB2 OPTIMIZED UPCONTROL GAIN .0034
035198,000282: # KDMIN INCREMENT ON Q7 TO DETECT END OF KEPLER PHASE .5 FPSS
035199,000283: # KTETA TIME OF FLIGHT CONSTANT 1000
035200,000284: # KLAT1 FACTOR IN KLAT CALC 1/24
035201,000285: # K44 GAIN USED IN INITIAL ROLL SECTION 19749550 FPS
035202,000286: # LATBIAS LATERAL SWITCH BIAS TERM .41252961 NM
035203,000287: # LEWD1 NOMINAL UPCONTROL L/D .15
035204,000288: # POINT1 FACTOR TO REDUCE UPCONTROL GAIN .1
035205,000289: # Q2 FINAL PHASE RANGE - 23500 Q3 -1002 NM
035206,000290: # Q3 FINAL PHASE DRANGE/D V .07 NM/FPS
035207,000291: # Q5 FINAL PHASE DRANGE/D GAMMA 7050 NM/RAD
035208,000292: # Q6 FINAL PHASE INITIAL FLIGHT PATH ANGLE .0349 RAD
035209,000293: # Q7F MIN DRAG FOR UPCONTROL 6 FPSS
035210,000294: # Q7MIN IN VALUE FOR Q7 IN FACTOR CALCULATION 40 FPSS
035211,000295: # Q19 FACTOR IN GAMMAL1 CALCULATION .5
035212,000296: # Q21 FACTOR IN Q2 CALCULATION 1000 NM
035213,000297: # Q22 FACTOR IN Q2 CALCULATION -1302 NM
035214,000298: # VFINAL1 VELOCITY TO START FINAL PHASE ON INITIAL ENTRY 27000 FPS
035215,000299: # VFINAL FACTOR IN INITIAL UP-DOWN CALC 26600 FPS
035216,000300: # VLMIN MINIMUM VL 18000 FPS
035217,000301: # VMIN VELOCITY TO SWITCH TO RELATIVE VEL VSAT/2
035218,000302: # VRCONTRL RDOT TO START INTO HUNTEST 700 FPS
035219,000303: # VRCONT=COMPUTER NAME
035220,000304: # 25NM TOLERANCE TO STOP RANGE ITERATION 25 NM
035221,000305: # VQUIT VELOCITY TO STOP STEERING 1000 FPS
035222,000306:
035223,000307: # Page 800
035224,000308: # CONVERSION FACTORS AND SCALING CONSTANTS
035225,000309: # ----------------------------------------
035226,000310:
035227,000311: # ATK ANGLE IN RAD TO NM 3437.7466 NM/RAD
035228,000312: # G5 NOMINAL G VALUE FOR SCALING (?) FPSS
035229,000313: # H5 ATMOSPHERE SCALE HEIGHT 28500 FT
035230,000314: # J GRAVITY HARMONIC COEFFICIENT .00162346
035231,000315: # (?) EQUATORIAL EARTH RATE 1546.10168 FPS
035232,000316: # MUE EARTH GRAVITATIONAL CONSTANT 3.986032233 E14 CUBIC M/ SEC SEC
035233,000317: # RE EARTH RADIUS 21202900 FT
035234,000318: # REQ EARTH EQUATORIAL RADIUS 20925738.2 FT
035235,000319: # VSAT SATELLITE VELOCITY AT RE 25766.1973 FPS
035236,000320: # WIE EARTH RATE .0000729211505 RAD/SEC
035237,000321:
035238,000322: # (END GSOP AS-276, VOL 1, FIG. 5.6-3 CONSTANTS, GAINS, ETC.)
035239,000323:
035240,000324: # DISPLAY QUANTITIES
035241,000325: # ------------------
035242,000326:
035243,000327: # (SEE SECTION 4 OF THE GSOP FOR SIGN CONVENTIONS.)
035244,000328:
035245,000329: # VARIABLE DESCRIPTION MAXIMUM VALUE
035246,000330: # -------- ----------- -------------
035247,000331:
035248,000332: # QMAX PREDICTED MAXIMUM ENTRY ACCEL 163.84 GS N 60
035249,000333: # VPRED PREDICTED VELOCITY AT ALTITUDE 128 M/CENTISEC N 60
035250,000334: # 400K FT ABOVE FISCHER RADIUS.
035251,000335: # GAMMAEI PREDICTED GAMMA AT ALTITUDE 1 REVOLUTION N 60
035252,000336: # 400K FT ABOVE FISCHER RADIUS
035253,000337: # D DRAG ACCELERATION 805 FPSS N 64
035254,000338: # VMAGI INERTIAL VELOCITY MAGNITUDE 128 M/CENTISEC N 64, N 68
035255,000339: # THETAH DESIRED RANGE ANGLE NM 1 REVOLUTION N 64, N 67
035256,000340: # LAT PRESENT LATITUDE 1 REVOLUTION N 67
035257,000341: # LONG PRESENT LONGITUDE 1 REVOLUTION N 67
035258,000342: # RTOGO RANGE ANGLE TO SPLASH FROM 1 REVOLUTION N 67
035259,000343: # EMSALT FT ABOVE FISCHER RADIUS (IN NM)
035260,000344: # VIO PREDICTED VELOCITY AT ALTITUDE 128 M/CENTISEC N 63
035261,000345: # EMSALT FT ABOVE FISCHER RADIUS.
035262,000346: # TTE TIME OF FREE FALL TO ALT B 28 CENTISEC N 63
035263,000347: # EMSALT FT ABOVE FISCHER RADIUS
035264,000348: # ROLLC ROLL COMMAND 1 REVOLUTION N 68, N 68, N 69
035265,000349: # LATANG CROSS-RANGE ERROR (XRNGERR) 4 RADIANS N 66
035266,000350: # DNRNGERR DOWN RANGE ERROR 1 REVOLUTION N 66
035267,000351: # (PREDANG - THETAH IN NM)
035268,000352: # HDOT ALTITUDE RATE 128 M/CENTISEC N 68
035269,000353: # QT MINIMUM DRAG FOR UPCONTROL 805 FPSS N 69
035270,000354: # VL EXIT VELOCITY FOR UP-CONTROL 2 VSAT N 69
035271,000355:
035272,000356: # Page 801
035273,000357: # BODY ATTITUDE QUANTITIES (CM/POSE)
035274,000358: # ----------------------------------
035275,000359:
035276,000360: # VARIABLE DECRIPTION MAXIMUM VALUE
035277,000361: # -------- ---------- -------------
035278,000362: # _
035279,000363: # -VREL NEGATIVE VELOCITY REL TO ATMOS. 2 VSAT
035280,000364: # _
035281,000365: # OLDUYA USED FOR UYA BELOW 1000 FPS 2
035282,000366: # _
035283,000367: # UXA/2 UNIT VECTOR TRIAD 2
035284,000368: # _
035285,000369: # UYA/2 BASED ON 2
035286,000370: # _
035287,000371: # UZA/2 THE TRAJECTORY 2
035288,000372: # _
035289,000373: # UBX/2 UNIT VECTOR 2
035290,000374: # _
035291,000375: # UBY/2 BODY TRIAD 2
035292,000376: # _
035293,000377: # UBZ/2 FOR CM. 2
035294,000378:
End of include-file ENTRY_LEXICON.agc. Parent file is MAIN.agc