Source Code
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These source-code files are part of a reconstructed copy of Skylark 048, the
Block II Command Module (CM) Apollo Guidance Computer (AGC) software for the
Skylab-2, Skylab-3, Skylab-4, and Apollo-Soyuz Test Project missions.
They have been created via disassembly of binary dumps of the original core rope
memory modules actually flown on Skylab-2, part numbers 2010802-541, 2010802-551,
2010802-561, 2010802-571, 2010802-581, and 2010802-591. Access to these modules
was provided by the New Mexico Museum of Space History, who we are much indebted to.
The source code for the Apollo 15, 16, and 17 software, Artemis 072, was used as
a starting point. Heavy use was made of TRW 4900.5-244, Programmed Guidance Equations
for Skylark Command Module Earth Orbital Program, dated 14 February 1972. This document
contains pseudocode of essentially all of Skylark, using original program labels which
have been copied for this source reconstruction.
Since only binary dumps (rather than listings) of Skylark are available as source material,
all comments and labels are approximate.
They have been taken from the Programmed Guidance Equations or other AGC programs where
possible, or, in some places, written from scratch to match what we believe would have
been in the original listing.
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054880,000002: ## Copyright: Public domain.
054881,000003: ## Filename: TIME_OF_FREE_FALL.agc
054882,000004: ## Purpose: A section of Skylark revision 048.
054883,000005: ## It is part of the source code for the Apollo Guidance Computer (AGC)
054884,000006: ## for Skylab-2, Skylab-3, Skylab-4, and ASTP. No original listings of
054885,000007: ## this software are available; instead, this file was created via
054886,000008: ## disassembly of dumps of the core rope modules actually flown on
054887,000009: ## Skylab-2. Access to these modules was provided by the New Mexico
054888,000010: ## Museum of Space History.
054889,000011: ## Assembler: yaYUL
054890,000012: ## Contact: Ron Burkey <info@sandroid.org>.
054891,000013: ## Website: www.ibiblio.org/apollo/index.html
054892,000014: ## Mod history: 2023-09-04 MAS Created from Artemis 072.
054893,000015:
054894,000016:
054895,000017: # THE TFF SUBROUTINES MAY BE USED IN EITHER EARTH OR MOON CENTERED COORDINATES. THE TFF ROUTINES NEVER
054896,000018: # KNOW WHICH ORIGIN APPLIES. IT IS THE USER WHO KNOWS, AND WHO SUPPLIES RONE, VONE AND 1/SQRT(MU) AT THE
054897,000019: # APPROPRIATE SCALE LEVEL FOR THE PROPER PRIMARY BODY.
054898,000020:
054899,000021: # EARTH ORIGIN POSITION -29 METERS
054900,000022: # VELOCITY -7 METERS/CENTISECOND
054901,000023: # 1/SQRT(MU) +17 SQRT(CS SQ/METERS CUBED)
054902,000024:
054903,000025: # MOON ORIGIN POSITION -27 METERS
054904,000026: # VELOCITY -5 METERS/CENTISECONDS
054905,000027: # 1/SQRT(MU) +14 SQRT(CS SQ/METERS CUBED)
054906,000028:
054907,000029: # ALL DATA PROVIDED TO AND RECEIVED FROM ANY TFF SUBROUTINE WILL BE AT ONE OF THE LEVELS ABOVE. IN ALL CASES,
054908,000030: # THE FREE FALL TIME IS RETURNED IN CENTISECONDS AT (-28). PROGRAM TFF/CONIC WILL GENERATE VONE/RTMU AND
054909,000031: # LEAVE IT IN VONE' AT (+10) IF EARTH ORIGIN AND (+9) IF MOON ORIGIN.
054910,000032:
054911,000033: # THE USER MUST STORE THE STATE VECTOR IN RONE, VONE AND MU IN THE FORM 1/SQRT(MU) IN TFF/RTMU
054912,000034: # AT THE PROPER SCALE BEFORE CALLING TFF/CONIC. SINCE RONE, VONE ARE IN THE EXTENDED VERB STORAGE AREA,
054913,000035: # THE USER MUST ALSO LOCK OUT THE EXTENDED VERBS, AND RELEASE THEM WHEN FINISHED.
054914,000036:
054915,000037: # PROGRAMS CALC/TFF AND CALC/TPER ASSUME THAT THE TERMINAL RADIUS IS LESS THAN THE PRESENT
054916,000038: # RADIUS. THIS RESTRICTION CAN BE REMOVED BY A 15 W CODING CHANGE, BUT AT PRESENT IT IS NOT DEEMED NECESSARY.
054917,000039:
054918,000040: # THE FOLLOWING ERASABLE QUANTITIES ARE USED BY THE TFF ROUTINES, AND ARE LOCATED IN THE PUSH LIST.
054919,000041:
054920,000042: # BELOW E: IS USED FOR EARTH ORIGIN SCALE
054921,000043: # M: IS USED FOR MOON ORIGIN SCALE
054922,000044:
054923,000045: # TFFSW = 119D BIT1 0 = CALCTFF 1 = CALCTPER
054924,000046: 23,3751 TFFDELQ = 10D # Q2-Q1 E: (-16) M: (-15)
054925,000047: 23,3751 RMAG1 = 12D # ABVAL(RN) M E: (-29) M: (-27)
054926,000048: # RPER = 14D PERIGEE RADIUS M E: (-29) M: (-27)
054927,000049: 23,3751 TFFQ1 = 14D # R.V / SQRT(MUE) E: (-16) M: (-15)
054928,000050: # SDELF/2 SIN(THETA) /2
054929,000051: 23,3751 CDELF/2 = 14D # COS(THETA) /2
054930,000052: # RAPO = 16D APOGEE RADIUS M E: (-29) M: (-27)
054931,000053: 23,3751 NRTERM = 16D # TERMINAL RADIUS M E: (-29+NR)
054932,000054: # M: (-27+NR)
054933,000055: 23,3751 RTERM = 18D # TERMINAL RADIUS M E: (-29) M: (-27)
054934,000056: 23,3751 TFFVSQ = 20D # -(V SQUARED/MU) 1/M E: (20) M: (18)
054935,000057: 23,3751 TFF1/ALF = 22D # SEMI MAJ AXIS M E: (-22-2 NA)
054936,000058: # M: (-20-2 NA)
054937,000059: 23,3751 TFFRTALF = 24D # SQRT(ALFA) E: (10+NA) M: (9+NA)
054938,000060: 23,3751 TFFALFA = 26D # ALFA 1/M E: (26-NR) M: (24-NR)
054939,000061: 23,3751 TFFNP = 28D # SEMI LATUS RECTUM M E: (-38+2 NR)
054940,000062: # M: (-36+2 NR)
054941,000063: 23,3751 TFF/RTMU = 30D # 1/SQRT(MU) E: (17) M: (14)
054942,000064: 23,3751 NRMAG = 32D # PRESENT RADIUS M E: (-29+NR)
054943,000065: # M: (-27+NR)
054944,000066: 23,3751 TFFX = 34D
054945,000067: 23,3751 TFFTEM = 36D # TEMPORARY
054946,000068:
054947,000069: # REGISTERS S1, S2 ARE UNTOUCHED BY ANY TFF SUBROUTINE
054948,000070: # INDEX REGISTERS X1, X2 ARE USED BY ALL TFF SUBROUTINES. THEY ARE ESTAB-
054949,000071: # LISHED IN TFF/CONIC AND MUST BE PRESERVED BETWEEN CALLS TO SUBSEQUENT
054950,000072: # SUBROUTINES.
054951,000073: # -NR C(X1) = NORM COUNT OF RMAG
054952,000074: # -NA C(X2) = NORM COUNT OF SQRT(ABS(ALFA))
054953,000075:
054954,000076:
054955,000077: # SUBROUTINE NAME: TFFCONIC DATE: 01.29.67
054956,000078: # MOD NO: 0 LOG SECTION: TIME OF FREE FALL
054957,000079: # MOD BY: RR BAIRNSFATHER
054958,000080: # MOD NO: 1 MOD BY: RR BAIRNSFATHER DATE: 11 APR 67
054959,000081: # MOD NO: 2 MOD BY: RR BAIRNSFATHER DATE: 21 NOV 67 ADD MOON MU.
054960,000082: # MOD NO: 3 MOD BY: RR BAIRNSFATHER DATE: 21 MAR 68 ACCEPT DIFFERENT EARTH/MOON SCALES
054961,000083:
054962,000084: # FUNCTIONAL DESCRIPTION: THIS SUBROUTINE IS CALLED TO COMPUTE THOSE CONIC PARAMETERS REQUIRED BY THE TFF
054963,000085: # SUBROUTINES AND TO ESTABLISH THEM IN THE PUSH LIST AREA. THE PARAMETERS ARE LISTED UNDER OUTPUT.
054964,000086: # THE EQUATIONS ARE
054965,000087: # - - -
054966,000088: # H = RN*VN ANGULAR MOMENTUM
054967,000089: # - -
054968,000090: # LCP = H.H / MU SEMI LATUS RECTUM
054969,000091: # - -
054970,000092: # ALFA = 2/RN - VN.VN / MU RECIPROCAL SEMI MAJ AXIS, SIGNED
054971,000093:
054972,000094: # AND ALFA IS POS FOR ELLIPTIC ORBITS
054973,000095: # 0 FOR PARABOLIC ORBITS
054974,000096: # NEG FOR HYPERBOLIC ORBITS.
054975,000097: # SUBROUTINE ALSO COMPUTES AND SAVES RMAG.
054976,000098:
054977,000099: # CALLING SEQUENCE:
054978,000100: # TFFCONIC EXPECTS CALLER TO ENTER WITH CORRECT GRAVITATIONAL CONSTANT IN MPAC, IN THE FORM
054979,000101: # 1/SQRT(MU). PROGRAM WILL SAVE IN TFF/RTMU . THE SCALE IS DETERMINED BY WHETHER EARTH OR MOON
054980,000102: # ORIGIN IS USED. THE CALLER MUST LOCK OUT THE EXTENDED VERBS BEFORE PROVIDING STATE VECTOR IN RONE,
054981,000103: # VONE AT PROPER SCALE. THE EXTENDED VERBS MUST BE RESTORED WHEN THE CALLER IS FINISHED USING THE
054982,000104: # TFF ROUTINES.
054983,000105:
054984,000106: # ENTRY POINT TFFCONMU EXPECTS THAT TFF/RTMU IS ALREADY LOADED.
054985,000107:
054986,000108: # TO SPECIFY MU: DLOAD CALL IF MU ALREADY STORED: CALL
054987,000109: # YOURMU 1/RTMU E: (17) M: (14) TFFCONMU
054988,000110: # TFFCONIC
054989,000111:
054990,000112: # PUSHLOC = PDL+0, ARBITRARY IF LEQ 18D
054991,000113:
054992,000114: # SUBROUTINES CALLED: NONE
054993,000115:
054994,000116: # NORMAL EXIT MODES: RVQ
054995,000117:
054996,000118: # ALARMS: NONE
054997,000119:
054998,000120: # OUTPUT: THE FOLLOWING ARE STORED IN THE PUSH LIST AREA.
054999,000121: # RMAG1 E:(-29) M:(-27) M RN, PRESENT RADIUS LENGTH.
055000,000122: # NRMAG E: (-29+NR) M RMAG, NORMALIZED
055001,000123: # M: (-27+NR)
055002,000124: # X1 -NR, NORM COUNT
055003,000125: # TFFNP E: (-38+2NR) M LCP, SEMI LATUS RECTUM, WEIGHTED BY NR. FOR VGAMCALC
055004,000126: # M: (-36+2NR)
055005,000127: # TFF/RTMU E:(17) M:(14) 1/SQRT(MU)
055006,000128: # TFFVSQ E:(20) M:(18) 1/M -(V SQ/MU): PRESENT VELOCITY, NORMLIZED. FOR VGAMCALC
055007,000129: # TFFALFA E: (26-NR) 1/M ALFA, WEIGHTED BY NR
055008,000130: # M: (24-NR)
055009,000131: # TFFRTALF E: (10+NA) SQRT(ALFA), NORMALIZED
055010,000132: # M: (9+NA)
055011,000133: # X2 -NA, NORM COUNT
055012,000134: # TFF1/ALF E: (-22-2NA) SIGNED SEMI MAJ AXIS, WEIGHTED BY NA
055013,000135: # M: (-20-2NA)
055014,000136: # PUSHLOC AT PDL+0
055015,000137: # THE FOLLOWING IS STORED IN GENERAL ERASABLE
055016,000138: # VONE' E:(10) M:(9) V/RT(MU), NORMALIZED VELOCITY
055017,000139:
055018,000140: # ERASABLE INITIALIZATION REQUIRED:
055019,000141: # RONE E:(-29) M:(-27) M STATE VECTOR LEFT BY CALLER
055020,000142: # VONE E:(-7) M:(-5) M/CS STATE VECTOR LEFT BY CALLER
055021,000143: # TFF/RTMU E:(17) M:(14) 1/RT(CS SQ/M CUBE) IF ENTER VIA TFFCONMU.
055022,000144:
055023,000145: # DEBRIS: QPRET, PDL+0 ... PDL+3
055024,000146:
055025,000147: 27,2000 SETLOC TOF-FF
055026,000148: 27,2000 BANK
055027,000149:
055028,000150: 27,3055 COUNT* $$/TFF
055029,000151:
055030,000152: 27,3055 00037 TFFCONIC STORE TFF/RTMU # 1/SQRT(MU) E: (17) M: (14)
055031,000153:
055032,000154: 27,3056 53575 TFFCONMU VLOAD UNIT # COME HERE WITH TFFRTMU LOADED.
055033,000155: 27,3057 02210 RONE # SAVED RN. M E: (-29) M: (-27)
055034,000156: 27,3060 77725 PDDL # UR/2 TO PDL+0, +5
055035,000157: 27,3061 00045 36D # MAGNITUDE
055036,000158: 27,3062 00015 STORE RMAG1 # M E: (-29) M: (-27)
055037,000159:
055038,000160: 27,3063 77701 NORM
055039,000161: 27,3064 00047 X1 # -NR
055040,000162: 27,3065 24041 STOVL NRMAG # RMAG M E: (-29+NR) M: (-27+NR)
055041,000163: 27,3066 02216 VONE # SAVED VN. M/CS E: (-7) M: (-5)
055042,000164: 27,3067 77761 VXSC
055043,000165: 27,3070 00037 TFF/RTMU # E: (17) M: (14)
055044,000166: 27,3071 02226 STORE VONE' # VN/SQRT(MU) E:(10) M:(9)
055045,000167:
055046,000168: 27,3072 47361 VXSC VXV
055047,000169: 27,3073 00041 NRMAG # E: (-29+NR) M: (-27+NR)
055048,000170: # UR/2 FROM PDL
055049,000171: 27,3074 47572 VSL1 VSQ # BEFORE: E:(-19+NR) M:(-18+NR)
055050,000172: 27,3075 14035 STODL TFFNP # LC P M E:(-38+2NR) M:(-36+2NR)
055051,000173: # SAVE ALSO FOR VGAMCALC
055052,000174: 27,3076 15174 TFF1/4
055053,000175: 27,3077 63271 DDV PDVL # (2/RMAG) 1/M E:(26-NR) M:(24-NR)
055054,000176: 27,3100 00041 NRMAG # RMAG M E:(-29+NR) M:(-27+NR)
055055,000177: 27,3101 02226 VONE' # SAVED VN. E: (10) M: (9)
055056,000178: 27,3102 57436 VSQ DCOMP # KEEP MPAC+2 HONEST FOR SQRT.
055057,000179: 27,3103 00025 STORE TFFVSQ # -(V SQ/MU) E:(20) M:(18)
055058,000180: # SAVE FOR VGAMCALC
055059,000181: 27,3104 43257 SR* DAD
055060,000182: 27,3105 20573 0 -6,1 # GET -VSQ/MU E:(26-NR) M:(24-NR)
055061,000183: 27,3106 77626 STADR
055062,000184: # 2/RMAG FROM PDL+2
055063,000185: 27,3107 77744 STORE TFFALFA # ALFA 1/M E:(26-NR) M:(24-NR)
055064,000186: 27,3110 41457 SL* PUSH # TEMP SAVE ALFA E:(20) M:(18)
055065,000187: 27,3111 20173 0 -6,1
055066,000188: 27,3112 75446 ABS SQRT # E:(10) M:(9)
055067,000189: 27,3113 77701 NORM
055068,000190: 27,3114 00050 X2 # X2 = -NA
055069,000191: 27,3115 00031 STORE TFFRTALF # SQRT( ABS(ALFA) ) E:(10+NA) M:(9+NA)
055070,000192: 27,3116 75316 DSQ SIGN # NOT SO ACCURATE, BUT OK
055071,000193: # ALFA FROM PDL+2 E:(20) M:(18)
055072,000194: 27,3117 55254 BZE BDDV # SET 1/ALFA =0, TO SHOW SMALL ALFA
055073,000195: 27,3120 57122 +2
055074,000196: 27,3121 15174 TFF1/4
055075,000197: 27,3122 00027 +2 STORE TFF1/ALF # 1/ALFA E:(-22-2 NA) M:(-20-2 NA)
055076,000198: 27,3123 77616 DUMPCNIC RVQ
055077,000199:
055078,000200: # 39 W
055079,000201:
055080,000202:
055081,000203: # SUBROUTINE NAME: TFFRP/RA DATE: 01.17.67
055082,000204: # MOD NO: 0 LOG SECTION: TIME OF FREE FALL
055083,000205: # MOD BY: RR BAIRNSFATHER
055084,000206: # MOD NO: 1 MOD BY: RR BAIRNSFATHER DATE: 11 APR 67
055085,000207: # MOD NO: 2 MOD BY: RR BAIRNSFATHER DATE: 21 MAR 68 ACCEPT DIFFERENT EARTH/MOON SCALES
055086,000208: # ALSO IMPROVE ACCURACY OF RAPO.
055087,000209:
055088,000210: # FUNCTIONAL DESCRIPTION: USED BY CALCTPER AND TFF DISPLAYS TO CALCULATE PERIGEE RADIUS AND ALSO
055089,000211: # APOGEE RADIUS FOR A GENERAL CONIC.
055090,000212: # PROGRAM GIVES PERIGEE RADIUS AS APOGEE RADIUS IS GIVEN BY
055091,000213: # RP = P /(1+E) RA = (1+E) / ALFA
055092,000214: # WHERE 2
055093,000215: # E = 1 - P ALFA
055094,000216: # IF RA IS NEGATIVE OR SHOWS DIVIDE OVERFLOW, THEN RA = POSMAX BECAUSE
055095,000217: # 1. APOGEE RADIUS IS NOT MEANINGFUL FOR HYPERBOLA
055096,000218: # 2. APOGEE RADIUS IS NOT DEFINED FOR PARABOLA
055097,000219: # 3. APOGEE RADIUS EXCEEDS THE SCALING FOR ELLIPSE.
055098,000220:
055099,000221: # THIS SUBROUTINE REQUIRES THE SIGNED RECIPROCAL SEMI MAJ AXIS, ALFA, AND SEMI LATUS RECTUM AS DATA.
055100,000222:
055101,000223: # CALLING SEQUENCE: CALL
055102,000224: # TFFRP/RA
055103,000225:
055104,000226: # PUSHLOC = PDL+0, ARBITRARY IF LEQ 10D
055105,000227: # C(MPAC) UNSPECIFIED
055106,000228:
055107,000229: # SUBROUTINES CALLED: NONE
055108,000230:
055109,000231: # NORMAL EXIT MODE: RVQ
055110,000232: # IF ELLIPSE, WITHIN NORMAL SCALING, RAPO IS CORRECT.
055111,000233: # OTHERWISE, RAPO = POSMAX.
055112,000234:
055113,000235: # ALARMS: NONE
055114,000236:
055115,000237: # OUTPUT: STORED IN PUSH LIST AREA. SCALE OF OUTPUT AGREES WITH DATA SUPPLIED TO TFF/CONIC.
055116,000238: # RPER E:(-29) M:(-27) M PERIGEE RADIUS DESTROYED BY CALCTFF/CALCTPER, TFFTRIG.
055117,000239: # RAPO E:(-29) M:(-27) M APOGEE RADIUS WILL BE DESTROYED BY CALCTFF/CALCTPER
055118,000240: # PUSHLOC AT PDL+0
055119,000241:
055120,000242: # ERASABLE INITIALIZATION REQUIRED:
055121,000243: # TFFALFA E:(26-NR) M 1/SEMI MAJ AXIS LEFT BY TFFCONIC
055122,000244: # M:(24-NR)
055123,000245: # TFFNP E:(-38+2NR) M LC P, SEMI LATUS RECTUM LEFT BY TFFCONIC
055124,000246: # M:(-36+2NR)
055125,000247: # X1 -NR, NORM COUNT OF RMAG LEFT BY TFFCONIC
055126,000248: # X2 -NA, NORM COUNT OF ALFA LEFT BY TFFCONIC
055127,000249:
055128,000250: # DEBRIS: QPRET, PDL+0 ... PDL+1
055129,000251:
055130,000252: 27,3124 RAPO = 16D # APOGEE RADIUS M E:(-29) M:(-27)
055131,000253: 27,3124 RPER = 14D # PERIGEE RADIUS M E:(-29) M:(-27)
055132,000254:
055133,000255: 27,3124 41345 TFFRP/RA DLOAD DMP
055134,000256: 27,3125 00033 TFFALFA # ALFA 1/M E:(26-NR) M:(24-NR)
055135,000257: 27,3126 00035 TFFNP # LC P M E:(-38+2NR) M:(-36+2NR)
055136,000258: 27,3127 57457 SR* DCOMP # ALFA P (-12+NR)
055137,000259: 27,3130 20571 0 -8D,1 # ALFA P (-4)
055138,000260: 27,3131 51415 DAD ABS # (DCOMP GIVES VALID TP RESULT FOR SQRT)
055139,000261: # (ABS PROTECTS SQRT IF E IS VERY NEAR 0)
055140,000262: 27,3132 17464 DP2(-4)
055141,000263: 27,3133 43366 SQRT DAD # E SQ = (1- P ALFA) (-4)
055142,000264: 27,3134 15174 TFF1/4
055143,000265: 27,3135 55206 PUSH BDDV # (1+E) (-2) TO PDL+0
055144,000266: 27,3136 00035 TFFNP # LCP M E:(-38+2NR) M:(-36+2NR)
055145,000267: 27,3137 53657 SR* SR* # (DOES SR THEN SL TO AVOID OVFL)
055146,000268: 27,3140 20601 0,1 # X1=-NR
055147,000269: 27,3141 20572 0 -7,1 # (EFFECTIVE SL)
055148,000270: 27,3142 14017 STODL RPER # PERIGEE RADIUS M E:(-29) M:(-27)
055149,000271: # (1+E) (-2) FROM PDL+0
055150,000272: 27,3143 41005 DMP BOVB
055151,000273: 27,3144 00027 TFF1/ALF # E:(-22-2NA) M:(-20-2NA)
055152,000274: 27,3145 57450 TCDANZIG # CLEAR OVFIND, IF ON.
055153,000275: 27,3146 53654 BZE SL*
055154,000276: 27,3147 57156 MAXRA # SET POSMAX, IF ALFA=0
055155,000277: 27,3150 57603 0 -5,2 # -5+NA
055156,000278: 27,3151 40057 SL* BOV
055157,000279: 27,3152 57576 0,2
055158,000280: 27,3153 57156 MAXRA # SET POSMAX IF OVFL.
055159,000281: 27,3154 77644 BPL # CONTINUE WITH VALID RAPO.
055160,000282: 27,3155 57160 +3
055161,000283: 27,3156 77745 MAXRA DLOAD # RAPO CALC IS NOT VALID. SET RAPO =
055162,000284: 27,3157 15212 NEARONE # POSMAX AS A TAG.
055163,000285: 27,3160 00021 +3 STORE RAPO # APOGEE RADIUS M E:(-29) M:(-27)
055164,000286: 27,3161 77616 DUMPRPRA RVQ
055165,000287:
055166,000288: # 30 W
055167,000289:
055168,000290:
055169,000291: # SUBROUTINE NAME: CALCTPER / CALCTFF DATE: 01.29.67
055170,000292: # MOD NO: 0 LOG SECTION: TIME OF FREE FALL
055171,000293: # MOD BY: RR BAIRNSFATHER
055172,000294: # MOD NO: 1 MOD BY: RR BAIRNSFATHER DATE: 21 MAR 67
055173,000295: # MOD NO: 2 MOD BY: RR BAIRNSFATHER DATE: 14 APR 67
055174,000296: # MOD NO: 3 MOD BY: RR BAIRNSFATHER DATE: 8 JUL 67 NEAR EARTH MUE AND NEG TFF (GONEPAST)
055175,000297: # MOD NO: 4 MOD BY: RR BAIRNSFATHER DATE: 21 NOV 67 ADD VARIABLE MU.
055176,000298: # MOD NO: 5 MOD BY: RR BAIRNSFATHER DATE: 21 MAR 68 ACCEPT DIFFERENT EARTH/MOON SCALES
055177,000299:
055178,000300: # FUNCTIONAL DESCRIPTION: PROGRAM CALCULATES THE FREE-FALL TIME OF FLIGHT FROM PRESENT POSITION RN AND
055179,000301: # VELOCITY VN TO A RADIUS LENGTH SPECIFIED BY RTERM , SUPPLIED BY THE USER. THE POSITION VECTOR
055180,000302: # RN MAY BE ON EITHER SIDE OF THE CONIC, BUT RTERM IS CONSIDERED ON THE INBOUND SIDE.
055181,000303: # THE EQUATIONS ARE
055182,000304:
055183,000305: # Q2 = -SQRT(RTERM (2-RTERM ALFA) - LCP) (INBOUND SIDE)) LEQ +- LCE/SQRT(ALFA)
055184,000306: # - -
055185,000307: # Q1 = RN.VN / SQRT(MU) LEQ +- LCE/SQRT(ALFA)
055186,000308:
055187,000309: # Z = NUM / DEN LEQ +- 1/SQRT(ALFA)
055188,000310:
055189,000311: # WHERE, IF INBOUND
055190,000312: # NUM = RTERM - RN LEQ +- 2 LCE/ALFA
055191,000313: # DEN = Q2+Q1 LEQ +- 2 LCE/SQRT(ALFA)
055192,000314:
055193,000315: # AND, IF OUTBOUND
055194,000316: # NUM = Q2-Q1 LEQ +- 2 LCE/SQRT(ALFA)
055195,000317: # DEN = 2 - ALFA (RTERM + RN) . LEQ +- 2 LCE
055196,000318:
055197,000319: # IF ALFA ZZ < 1.0 (FOR ALL CONICS EXCEPT ELLIPSES HAVING ABS(DEL ECC ANOM) G 90 DEG)
055198,000320:
055199,000321: # THEN X = ALFA Z Z
055200,000322: # AND TFF = (RTERM +RN -2 ZZ T(X) ) Z/SQRT(MU)
055201,000323:
055202,000324: # EXCEPT IF ALFA PNZ, AND IF TFF NEG,
055203,000325: # THEN TFF = 2 PI /(ALFA SQRT(ALFA)) + TFF
055204,000326:
055205,000327: # OR IF ALFA ZZ GEQ 1.0 (FOR ELLIPSES HAVING ABS(DEL ECC ANOM) GEQ 90 DEG)
055206,000328:
055207,000329: # THEN X = 1/ALFA Z Z
055208,000330: # AND TFF = (PI/SQRT(ALFA) -Q2 +Q1 +2(X T(X) -1) /ALFA Z) /ALFA SQRT(MU)
055209,000331:
055210,000332: # WHERE T(X) IS A POLYNOMIAL APPROXIMATION TO THE SERIES
055211,000333: # 2 3 2
055212,000334: # 1/3 - X/5 + X /7 - X /9 ... (X < 1.0)
055213,000335:
055214,000336: # CALLING SEQUENCE: TIME TO RTERM TIME TO PERIGEE
055215,000337: # CALL CALL
055216,000338: # CALCTFF CALCTPER
055217,000339: # C(MPAC) = TERMNL RAD M C(MPAC) = PERIGEE RAD M
055218,000340: # FOR EITHER, E: (-29) M: (-27)
055219,000341: # FOR EITHER, PUSHLOC = PDL+0 , ARBITRARY IF LEQ 8D.
055220,000342:
055221,000343: # SUBROUTINES CALLED: T(X), VIA RTB
055222,000344:
055223,000345: # NORMAL EXIT MODE: RVQ
055224,000346: # HOWEVER, PROGRAM EXITS WITH ONE OF THE FOLLOWING VALUES FOR TFF (-28) CS IN MPAC. USER MUST STORE.
055225,000347: # A. TFF = FLIGHT TIME. NORMAL CASE FOR POSITIVE FLIGHT TIME LESS THAN ONE ORBITAL PERIOD.
055226,000348: # B. (THIS OPTION IS NO LONGER USED.)
055227,000349: # C. TFF = POSMAX. THIS INDICATES THAT THE CONIC FROM THE PRESENT POSITION WILL NOT RETURN TO
055228,000350: # THE SPECIFIED ALTITUDE. ALSO INDICATES OUTBOUND PARABOLA OR HYPERBOLA.
055229,000351:
055230,000352: # OUTPUT: C(MPAC) (-28) CS TIME OF FLIGHT, OR TIME TO PERIGEE
055231,000353: # TFFX (0) X, LEFT FOR ENTRY DISPLAY TFF ROUTINES
055232,000354: # NRTERM E: (-29+NR) M RTERM, WEIGHTED BY NR LEFT FOR ENTRY DISPLAY TFF ROUTINES
055233,000355: # M: (-27+NR)
055234,000356: # TFFTEM E: (-59+2NR) LCP Z Z SGN(SDELF) LEFT FOR ENTRY DISPLAY TFF ROUTINES
055235,000357: # M: (-55+2NR) LCP /ALFA SGN(SDELF) LEFT FOR ENTRY DISPLAY TFF ROUTINES
055236,000358: # NOTE: TFFTEM = PDL 36D AND WILL BE DESTROYED BY .:UNIT:.
055237,000359: # RMAG1 E:(-29) M:(-27) PDL 12 NOT TOUCHED.
055238,000360: # TFFQ1 E:(-16) M:(-15) PDL 14D
055239,000361: # TFFDELQ E:(-16) M:(-15) PDL 10D
055240,000362: # PUSHLOC AT PDL+0
055241,000363:
055242,000364: # ERASABLE INITIALIZATION REQUIRED:
055243,000365: # RONE E:(-29) M:(-27) M STATE VECTOR LEFT BY USER
055244,000366: # VONE' E:(+10) M:(+9) VN/SQRT(MU) LEFT BY TFF/CONIC
055245,000367: # RMAG1 E:(-29) M:(-27) PRESENT RADIUS, M LEFT BY TFFCONIC
055246,000368: # C(MPAC) E:(-29) M:(-27) RTERM, TERMINAL RADIUS LENGTH, M LEFT BY USER
055247,000369:
055248,000370: # THE FOLLOWING ARE STORED IN THE PUSH LIST AREA.
055249,000371: # TFF/RTMU E:(17) M:(14) 1/SQRT(MU) LEFT BY TFFCONIC.
055250,000372: # NRMAG E: (-29+NR) M RMAG, NORMALIZED LEFT BY TFFCONIC
055251,000373: # M: (-27+NR)
055252,000374: # X1 -NR, NORM COUNT LEFT BY TFFCONIC
055253,000375: # TFFNP E: (-38+2NR) M LCP, SEMI LATUS RECTUM, WEIGHT NR LEFT BY TFFCONIC
055254,000376: # M: (-36+2NR)
055255,000377: # TFFALFA E: (26-NR) 1/M ALFA, WEIGHT NR LEFT BY TFFCONIC
055256,000378: # M: (24-NR)
055257,000379: # TFFRTALF E:(10+NA) SQRT(ALFA), NORMALIZED LEFT BY TFFCONIC
055258,000380: # M:(9+NA)
055259,000381: # X2 -NA, NORM COUNT LEFT BY TFFCONIC
055260,000382: # TFF1/ALF E: (-22-2NA) SIGNED SEMIMAJ AXIS, WEIGHTED BY NA LEFT BY TFFCONIC
055261,000383: # M: (-20-2NA)
055262,000384:
055263,000385: # DEBRIS: QPRET, PDL+0 ... PDL+3
055264,000386: # RTERM E:(-29) M:(-27) RTERM, TERMINAL RADIUS LENGTH
055265,000387: # RAPO E:(-29) M:(-27) PDL 16D (=NRTERM)
055266,000388: # RPER E:(-29) M:(-27) PDL 14D (=TFFQ1)
055267,000389:
055268,000390: 27,3162 77614 CALCTPER SETGO # ENTER WITH RPER IN MPAC
055269,000391: 27,3163 03436 TFFSW
055270,000392: 27,3164 57167 +3
055271,000393: 27,3165 77614 CALCTFF CLEAR # ENTER WITH RTERM IN MPAC
055272,000394: 27,3166 03676 TFFSW
055273,000395: 27,3167 00023 +3 STORE RTERM # E: (-29) M: (-27)
055274,000396: 27,3170 77657 SL*
055275,000397: 27,3171 20201 0,1 # X1=-NR
055276,000398: 27,3172 00021 STORE NRTERM # RTERM E: (-29+NR) M: (-27+NR)
055277,000399: 27,3173 44205 DMP BDSU
055278,000400: 27,3174 00033 TFFALFA # ALFA E: (26-NR) M: (24-NR)
055279,000401: 27,3175 15174 TFF1/4
055280,000402: 27,3176 41206 PUSH DMP # (2-ALFA RTERM) (-3) TO PDL+0
055281,000403: 27,3177 00021 NRTERM # E: (-29+NR) M: (-27+NR)
055282,000404: 27,3200 53725 PDDL SR* # RTERM(2-ALFA RTERM) TO PDL+2
055283,000405: # E: (-32+NR) M: (-30+NR)
055284,000406: 27,3201 00035 TFFNP # LC P E:(-38+2NR) M:(-36+2NR)
055285,000407: 27,3202 20573 0 -6,1 # X1 = -NR
055286,000408: 27,3203 43276 DCOMP DAD # DUE TO SHIFTS, KEEP PRECISION FOR SQRT
055287,000409: # RTERM(2-ALFA RTERM) FROM PDL +2
055288,000410: # E: (-32+NR) M: (-30+NR)
055289,000411: 27,3204 77657 SR* # LEAVE E: (-32) M: (-30)
055290,000412: 27,3205 20601 0,1 # X1 = -NR
055291,000413: 27,3206 71214 BOFF DLOAD # CHECK TFF /TPER SWITCH
055292,000414: 27,3207 03756 TFFSW
055293,000415: 27,3210 57212 +2 # IF TFF, CONTINUE
055294,000416: 27,3211 15204 TFFZEROS # IF TPER, SET Q2 = 0
055295,000417: 27,3212 75440 +2 BMN SQRT # E: (-16) M: (-15)
055296,000418:
055297,000419: 27,3213 57345 MAXTFF1 # NO FREE FALL CONIC TO RTERM FROM HERE
055298,000420: # RESET PDL, SET TFF=POSMAX, AND EXIT.
055299,000421:
055300,000422: 27,3214 41076 DCOMP BOVB # RT IS ON INBOUND SIDE. ASSURE OVFIND=0
055301,000423: 27,3215 57450 TCDANZIG # ANY PORT IN A STORM.
055302,000424: 27,3216 24045 STOVL TFFTEM # Q2 E: (-16) M: (-15)
055303,000425: 27,3217 02226 VONE' # VN/SQRT(MU) E: (10) M: (9)
055304,000426: 27,3220 52441 DOT SL3
055305,000427: 27,3221 02210 RONE # SAVED RN. E: (-29) M: (-27)
055306,000428: 27,3222 00017 STORE TFFQ1 # Q1, SAVE FOR GONEPAST TEST.
055307,000429: # E: (-16) M: (-15)
055308,000430: 27,3223 44240 BMN BDSU
055309,000431: 27,3224 57245 INBOUND # USE ALTERNATE Z
055310,000432: 27,3225 00045 TFFTEM # Q2 E: (-16) M: (-15)
055311,000433:
055312,000434: # OUTBOUND Z CALC CONTINUES HERE
055313,000435:
055314,000436: 27,3226 14043 STODL TFFX # NUM=Q2-Q1 E: (-16) M: (-15)
055315,000437: 27,3227 00033 TFFALFA # ALFA E: (26-NR) M: (24-NR)
055316,000438: 27,3230 44205 DMP BDSU
055317,000439: 27,3231 00041 NRMAG # RMAG E: (-29+NR) M: (-27+NR)
055318,000440: # (2-RTERM ALFA) (-3) FROM PDL+0
055319,000441: 27,3232 51406 SAVEDEN PUSH ABS # DEN TO PDL+0 E: (-3) OR (-16)
055320,000442: # M: (-3) OR (-15)
055321,000443: 27,3233 40015 DAD BOV # INDETERMINANCY TEST
055322,000444: 27,3234 17456 LIM(-22) # =1.0-B(-22)
055323,000445: 27,3235 57256 TFFXTEST # GO IF DEN >/= B(-22)
055324,000446: 27,3236 65345 DLOAD PDDL # SET DEN=0 OTHERWISE
055325,000447: 27,3237 15204 TFFZEROS
055326,000448: # XCH ZERO WITH PDL+0
055327,000449: 27,3240 57545 DLOAD DCOMP
055328,000450: 27,3241 00033 TFFALFA # ALFA E: (26-NR) M: (24-NR)
055329,000451: 27,3242 71240 BMN DLOAD # FOR TPER: Z INDET AT DELE/2=0 AND 90.
055330,000452: 27,3243 57352 TFFEL1 # ASSUME 90, AND LEAVE 0 IN PDL: 1/Z=D/N
055331,000453:
055332,000454: # Z INDET. AT PERIGEE FOR PARAB OR HYPERB.
055333,000455: 27,3244 77616 DUMPTFF1 RVQ # RETURN TFF =0
055334,000456:
055335,000457: # INBOUND Z CALC CONTINUES HERE
055336,000458: 27,3245 77745 INBOUND DLOAD # RESET PDL+0
055337,000459: 27,3246 45345 DLOAD DSU # ALTERNATE Z CALC
055338,000460: 27,3247 00023 RTERM # E: (-29) M: (-27)
055339,000461: 27,3250 00015 RMAG1 # E: (-29) M: (-27)
055340,000462: 27,3251 14043 STODL TFFX # NUM=RTERM-RN E: (-29) M: (-27)
055341,000463: 27,3252 00045 TFFTEM # Q2 E: (-16) M: (-15)
055342,000464: 27,3253 52015 DAD GOTO
055343,000465: 27,3254 00017 TFFQ1 # Q1 E: (-16) M:(-15)
055344,000466: 27,3255 57232 SAVEDEN # DEN = Q2+Q1 E: (-16) M: (-15)
055345,000467:
055346,000468: 27,3256 65215 TFFXTEST DAD PDDL # (ABS(DEN) TO PDL+2)) E: (-3) OR (-16)
055347,000469: # M: (-3) OR (-15)
055348,000470: 27,3257 17460 DP(-22) # RESTORE ABS(DEN) TO MPAC
055349,000471: 27,3260 00043 TFFX # NUM E:(-16) OR (-29) M:(-15) OR (-27)
055350,000472: 27,3261 53605 DMP SR*
055351,000473: 27,3262 00031 TFFRTALF # SQRT(ALFA) E: (10+NA) M: (9+NA)
055352,000474: 27,3263 57201 0 -3,2 # X2=-NA
055353,000475: 27,3264 77671 DDV # C(MPAC) =NUM SQRT(ALFA) E:(-3) OR (-16)
055354,000476: # M:(-3) OR (-15)
055355,000477: # ABS(DEN) FROM PDL+2 E:(-3) OR (-16)
055356,000478: # M:(-3) OR (-15)
055357,000479: 27,3265 40145 DLOAD BOV # (THE DLOAD IS SHARED WITH TFFELL)
055358,000480: 27,3266 00043 TFFX # NUM E: (-16) OR (-29) M:(-15) OR (-27)
055359,000481: 27,3267 57350 TFFELL # USE EQN FOR DELE GEQ 90, LEQ -90
055360,000482:
055361,000483: # OTHERWISE, CONTINUE FOR GENERAL CONIC FOR TFF EQN
055362,000484:
055363,000485: 27,3270 45471 DDV STADR
055364,000486: # DEN FROM PDL+0 E: (-3) OR (-16)
055365,000487: # M: (-3) OR (-15)
055366,000488: 27,3271 77732 STORE TFFTEM # Z SAVE FOR SIGN OF SDELF.
055367,000489: # E: (-13) M: (-12)
055368,000490: 27,3272 63406 PUSH DSQ # Z TO PDL+0
055369,000491: 27,3273 41206 PUSH DMP # Z SQ TO PDL+2 E: (-26) M: (-24)
055370,000492: 27,3274 00035 TFFNP # LC P E: (-38+2NR) M: (-36+2NR)
055371,000493: 27,3275 75261 SL SIGN
055372,000494: 27,3276 20206 5
055373,000495: 27,3277 00045 TFFTEM # AFFIX SIGN FOR SDELF (ENTRY DISPLAY)
055374,000496: 27,3300 14045 STODL TFFTEM # P ZSQ E: (-59+2NR) M: (-55+2NR)
055375,000497: # (ARG IS USED IN TFF/TRIG)
055376,000498: # ZSQ FROM PDL+2 E: (-26) M: (-24)
055377,000499: 27,3301 41206 PUSH DMP # RESTORE PUSH LOC
055378,000500: 27,3302 00033 TFFALFA # ALFA E: (26-NR) M: (24-NR)
055379,000501: 27,3303 77657 SL*
055380,000502: 27,3304 20201 0,1 # X1=-NR
055381,000503: 27,3305 00043 STORE TFFX # X
055382,000504: 27,3306 41234 RTB DMP
055383,000505: 27,3307 57432 T(X) # POLY
055384,000506: # ZSQ FROM PDL+2 E: (-26) M: (-24)
055385,000507: 27,3310 44302 SR2 BDSU # 2 ZSQ T(X) E: (-29) M: (-27)
055386,000508: 27,3311 00023 RTERM # RTERM E: (-29) M: (-27)
055387,000509: 27,3312 41215 DAD DMP
055388,000510: 27,3313 00015 RMAG1 # E: (-29) M: (-27)
055389,000511: # Z FROM PDL+0 E: (-13) M: (-12)
055390,000512: 27,3314 51042 SR3 BPL # TFF SQRT(MU) E: (-45) M: (-42)
055391,000513: 27,3315 57336 ENDTFF # (NO PUSH UP)
055392,000514: 27,3316 75206 PUSH SIGN # TFF SQRT(MU) TO PDL+0
055393,000515: 27,3317 00017 TFFQ1 # Q1 FOR GONEPAST TEST
055394,000516: 27,3320 71244 BPL DLOAD # GONE PAST ?
055395,000517: 27,3321 57342 NEGTFF # YES. TFF < 0.
055396,000518: 27,3322 00027 TFF1/ALF # 1/ALFA E: (-22-2NA) M: (-20-2NA)
055397,000519: 27,3323 51076 DCOMP BPL # ALFA > 0 ?
055398,000520: 27,3324 57342 NEGTFF # NO. TFF IS NEGATIVE.
055399,000521:
055400,000522: # CORRECT FOR ORBITAL PERIOD.
055401,000523:
055402,000524: 27,3325 77676 DCOMP # YES. CORRECT FOR ORB PERIOD.
055403,000525: 27,3326 56205 DMP DDV
055404,000526: 27,3327 17454 PI/16 # 2 PI (-5)
055405,000527: 27,3330 00031 TFFRTALF # SQRT(ALFA) E: (10+NA) M: (9+NA)
055406,000528: 27,3331 53657 SL* SL*
055407,000529: 27,3332 57602 0 -4,2 # X2=-NA
055408,000530: 27,3333 57602 0 -4,2
055409,000531: 27,3334 43257 SL* DAD
055410,000532: 27,3335 57576 0,2
055411,000533: # TFF SQRT(MU) FROM PDL+0 E:(-45) M:(-42)
055412,000534: 27,3336 40005 ENDTFF DMP BOV # TFF SQRT(MU) IN MPAC E:(-45) M:(-42)
055413,000535: 27,3337 00037 TFF/RTMU # E: (17) M: (14)
055414,000536: 27,3340 57346 MAXTFF # SET POSMAX IF OVFL.
055415,000537:
055416,000538: 27,3341 77616 DUMPTFF2 RVQ # RETURN TFF (-28) CS IN MPAC.
055417,000539:
055418,000540: 27,3342 77745 NEGTFF DLOAD
055419,000541: # TFF SQRT(MU) FROM PDL+0, NEGATIVE.
055420,000542: 27,3343 77650 GOTO
055421,000543: 27,3344 57336 ENDTFF
055422,000544:
055423,000545: 27,3345 77745 MAXTFF1 DLOAD # RESET PDL
055424,000546: 27,3346 43545 MAXTFF DLOAD RVQ
055425,000547: 27,3347 15212 NEARONE
055426,000548:
055427,000549: # TIME OF FLIGHT ELLIPSE WHEN DEL (ECCENTRIC ANOM) GEQ 90 AND LEQ -90.
055428,000550:
055429,000551: # NUM FROM TFFX. E: (-16) OR (-29)
055430,000552: # M: (-15) OR (-27)
055431,000553: 27,3350 77712 TFFELL SL2 # NUM E:(-14) OR (-27) M:(-13) OR (-25)
055432,000554: 27,3351 41465 BDDV PUSH # TEMP SAVE D/N IN PDL+0
055433,000555: # DEN FROM PDL+0 E:(-3)/( 16) M:(-3)/(-15)
055434,000556: # N/D TO PDL+0 E: (11) M: (10)
055435,000557: 27,3352 45345 TFFEL1 DLOAD DSU # (ENTER WITH D/N=0 IN PDL+0)
055436,000558: 27,3353 00045 TFFTEM # Q2 E: (-16) M: (-15)
055437,000559: 27,3354 00017 TFFQ1 # Q1 E: (-16) M: (-15)
055438,000560: 27,3355 14013 STODL TFFDELQ # Q2-Q1 E: (-16) M: (-15)
055439,000561: # D/N FROM PDL+0
055440,000562: 27,3356 77626 STADR
055441,000563: 27,3357 77732 STORE TFFTEM # D/N E: (11) M: (10)
055442,000564: 27,3360 53605 DMP SL*
055443,000565: 27,3361 00027 TFF1/ALF # 1/ALFA E: (-22-2NA) M: (-20-2NA)
055444,000566: 27,3362 57576 0,2 # 1/ALFA Z E: (-11-NA) M: (-10-NA)
055445,000567: 27,3363 41206 PUSH DMP # TO PDL+0
055446,000568: 27,3364 00045 TFFTEM # 1/Z E: (11) M: (10)
055447,000569: 27,3365 41057 SL* BOVB
055448,000570: 27,3366 57576 0,2 # X2= -NA
055449,000571: 27,3367 45742 SIGNMPAC # IN CASE X= 1.0, CONTINUE
055450,000572: 27,3370 00043 STORE TFFX # X=1/ALFA ZSQ
055451,000573: 27,3371 41234 RTB DMP
055452,000574: 27,3372 57432 T(X) # POLY
055453,000575: 27,3373 00043 TFFX
055454,000576: 27,3374 45242 SR3 DSU
055455,000577: 27,3375 17462 DP2(-3)
055456,000578: 27,3376 41405 DMP PUSH # 2(X T(X)-1) /Z ALFA E: (-15-NA)
055457,000579: # M: (-14-NA)
055458,000580: # 1/ALFA Z FROM PDL+0 E: (-11-NA)
055459,000581: # M: (-10-NA)
055460,000582: 27,3377 41345 DLOAD DMP # GET SIGN FOR SDELF
055461,000583: 27,3400 00045 TFFTEM # 1/Z E: (11) M: (10)
055462,000584: 27,3401 00015 RMAG1 # E: (-29) M: (-27)
055463,000585: 27,3402 43312 SL2 DAD
055464,000586: 27,3403 00017 TFFQ1 # Q1 E: (-16) M: (-15)
055465,000587: 27,3404 14045 STODL TFFTEM # (Q1+R 1/Z) =SGN OF SDELF E:(-16) M:(-15
055466,000588: 27,3405 00035 TFFNP # LC P E: (-38+2NR) M: (-36+2NR)
055467,000589: 27,3406 53605 DMP SL* # CALC FOR ARG FOR TFF/TRIG.
055468,000590: 27,3407 00027 TFF1/ALF # 1/ALFA E:(-22-2NA) M:(-20-2NA)
055469,000591: 27,3410 57575 1,2 # X2=-NA
055470,000592: 27,3411 53765 SIGN SL*
055471,000593: 27,3412 00045 TFFTEM # AFFIX SIGN FOR SDELF
055472,000594: 27,3413 57576 0,2
055473,000595: 27,3414 14045 STODL TFFTEM # P/ALFA E:(-59+2NR) M:(-55+2NR)
055474,000596: # (ARG FOR USE IN TFF/TRIG)
055475,000597: 27,3415 00027 TFF1/ALF # 1/ALFA E:(-22-2NA) M:(-20-2NA)
055476,000598: 27,3416 41366 SQRT DMP
055477,000599: 27,3417 17454 PI/16 # PI (-4)
055478,000600: 27,3420 77615 DAD
055479,000601: # 2(XT(X)-1)/Z ALFA FROM PDL E:(-15-NA)
055480,000602: # M:(-14-NA)
055481,000603: 27,3421 45257 SL* DSU
055482,000604: 27,3422 57577 0 -1,2
055483,000605: 27,3423 00013 TFFDELQ # Q2-Q1 E: (-16) M: (-15)
055484,000606: 27,3424 53605 DMP SL*
055485,000607: 27,3425 00027 TFF1/ALF # 1/ALFA E:(-22-2NA) M:(-20-2NA)
055486,000608: 27,3426 57601 0 -3,2
055487,000609: 27,3427 52057 SL* GOTO
055488,000610: 27,3430 57602 0 -4,2
055489,000611: 27,3431 57336 ENDTFF # TFF SQRT(MU) IN MPAC E:(-45) M:(-42)
055490,000612:
055491,000613:
055492,000614: # PROGRAM NAME: T(X) DATE: 01.17.67
055493,000615: # MOD NO: 0 LOG SECTION: TIME OF FREE FALL
055494,000616: # MOD BY: RR BAIRNSFATHER
055495,000617:
055496,000618: # FUNCTIONAL DESCRIPTION: THE POLYNOMIAL T(X) IS USED BY TIME OF FLIGHT SUBROUTINES CALCTFF AND
055497,000619: # CALCTPER TO APPROXIMATE THE SERIES
055498,000620: # 2 3
055499,000621: # 1/3 -X/5 +X /7 -X /9 ...
055500,000622:
055501,000623: # WHERE X = ALFA Z Z IF ALFA Z Z LEQ 1
055502,000624: # X = 1/(ALFA Z Z) IF ALFA Z Z G 1
055503,000625:
055504,000626: # ALSO X IS NEG FOR HYPERBOLIC ORBITS
055505,000627: # X = 0 FOR PARABOLIC ORBITS
055506,000628: # X IS POSITIVE FOR ELLIPTIC ORBITS
055507,000629: # FOR FLIGHT 278, THE POLYNOMIAL T(X) IS FITTED OVER THE RANGE (0,+1) AND HAS A MAXIMUM
055508,000630: # DEVIATION FROM THE SERIES OF 2 E-5 (T(X) IS A CHEBYCHEV TYPE FIT AND WAS OBTAINED USING
055509,000631: # MAC PROGRAM AUTCURFIT294RRB AND IS VALID TO THE SAME TOLERANCE OVER THE RANGE (-.08,+1). )
055510,000632:
055511,000633: # CALLING SEQUENCE: RTB
055512,000634: # T(X)
055513,000635: # C(MPAC) = X
055514,000636:
055515,000637: # SUBROUTINES CALLED: NONE
055516,000638:
055517,000639: # NORMAL EXIT MODE: TC DANZIG
055518,000640:
055519,000641: # ALARMS: NONE
055520,000642:
055521,000643: # OUTPUT: C(MPAC) = T(X)
055522,000644:
055523,000645: # ERASABLE INITIALIZATION REQUIRED:
055524,000646: # C(MPAC) = X
055525,000647:
055526,000648: # DEBRIS: NONE
055527,000649:
055528,000650: 27,3432 07171 T(X) TC POLY
055529,000651: 27,3433 00004 DEC 4 B-14 # N-1
055530,000652: 27,3434 12525 12525 2DEC 3.333333333 E-1
055531,000653: 27,3436 71463 57703 2DEC* -1.999819135 E-1*
055532,000654: 27,3440 04423 17645 2DEC* 1.418148467 E-1*
055533,000655: 27,3442 74604 43667 2DEC* -1.01310997 E-1*
055534,000656: 27,3444 01626 37256 2DEC* 5.609004986 E-2*
055535,000657: 27,3446 77404 52071 2DEC* -1.536156925 E-2*
055536,000658:
055537,000659: 27,3450 06030 ENDT(X) TC DANZIG
055538,000660:
055539,000661: 27,3451 27,3450 TCDANZIG = ENDT(X)
055540,000662:
055541,000663: # TFF CONSTANTS
055542,000664:
055543,000665: 27,2000 SETLOC TOF-FF1
055544,000666: 27,2000 BANK
055545,000667:
055546,000668: 27,3451 COUNT* $$/TFF
055547,000669: # NOTE _ NOTE _ ADJUSTED MUE FOR NEAR EARTH TRAJ.
055548,000670:
055549,000671:
055550,000672: # MUE = 3.990815471 E10 M CUBE/CS SQ
055551,000673: # RTMUE = 1.997702549 E5 B-18* MODIFIED EARTH MU
055552,000674:
055553,000675: 27,3451 24775 30424 1/RTMU 2DEC* .5005750271 E-5 B17* # MODIFIED EARTH MU
055554,000676:
055555,000677: # NOTE _ NOTE _ ADJUSTED MUE FOR NEAR EARTH TRAJ.
055556,000678: # MUM = 4.902778 E8 M CUBE/CS SQ
055557,000679: # RTMUM 2DEC* 2.21422176 E4 B-18*
055558,000680: 27,3453 06220 37553 PI/16 2DEC 3.141592653 B-4
055559,000681: 27,3455 37777 37700 LIM(-22) 2OCT 3777737700 # 1.0 -B(-22)
055560,000682: 27,3457 00000 00100 DP(-22) 2OCT 0000000100 # B(-22)
055561,000683: 27,3461 04000 00000 DP2(-3) 2DEC 1 B-3
055562,000684: 27,3463 02000 00000 DP2(-4) 2DEC 1 B-4 # 1/16
055563,000685:
055564,000686: # RPAD1 2DEC 6373338 B-29 M (-29) = 20 909 901.57 FT
055565,000687: 27,3465 22,3373 RPAD1 = RPAD
055566,000688: 27,3465 26,3211 NEARONE EQUALS DPPOSMAX
055567,000689: 27,3465 26,3203 TFFZEROS EQUALS HI6ZEROS
055568,000690: 27,3465 26,3173 TFF1/4 EQUALS HIDP1/4
End of include-file TIME_OF_FREE_FALL.agc. Parent file is MAIN.agc