# Copyright: Public domain. # Filename: STABLE_ORBIT.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 <info@sandroid.org>. # Website: www.ibiblio.org/apollo. # Pages: 723-730 # Mod history: 2009-05-19 RSB Adapted from the corresponding # Colossus249 file (there being no corresponding # Luminary131 source-code file), using page # images from Luminary 1A. # 2009-06-07 RSB Eliminated an extraneous instruction. # 2011-01-06 JL Fixed pseudo-label indentation. # # 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 2021112-061 # 16:27 JULY 14, 1969
# Page 723 # STABLE ORBIT RENDEZVOUS PROGRAMS (P38 AND P78) # # MOD NO -1 LOG SECTION - STABLE ORBIT - P38-P39 # MOD BY RUDNICKI.S DATE 25JAN68 # # FUNCTIONAL DESCRIPTION # # P38 AND P78 CALCULATE THE REQUIRED DELTA V AND OTHER INITIAL # CONDITIONS REQUIRED BY THE AGC TO (1) PUT THE ACTIVE VEHICLE # ON A TRANSFER TRAJECTORY THAT INTERCEPTS THE PASSIVE VEHICLE # ORBIT A GIVEN DISTANCE, DELTA R, EITHER AHEAD OF OR BEHIND THE # PASSIVE VEHICLE AND (2) ACTUALLY PLACE THE ACTIVE VEHICLE IN THE # PASSIVE VEHICLE ORBIT WITH A DELTA R SEPARATION BETWEEN THE TWO # VEHICLES # # CALLING SEQUENCE # # ASTRONAUT REQUEST THRU DSKY # # V37E38E IF THIS VEHICLE IS ACTIVE VEHICLE # V37E78E IF OTHER VEHICLE IS ACTIVE VEHICLE # # INPUT # # (1) SOI MANEUVER # # (A) TIG TIME OF SOI MANEUVER # (B) CENTANG ORBITAL CENTRAL ANGLE OF THE PASSIVE VEHICLE # DURING THE TRANSFER FROM TIG TO TIME OF INTERCEPT # (C) DELTAR THE DESIRED SEPARATION OF THE TWO VEHICLES # SPECIFIED AS A DISTANCE ALONG THE PASSIVE VEHICLE # ORBIT # (D) OPTION EQUALS 1 FOR SOI # # (2) SOR MANEUVER # # (A) TIG TIME OF SOR MANEUVER # (B) CENTANG AN OPTIONAL RESPECIFICATION OF 1 (B) ABOVE # (C) OPTION EQUALS 2 FOR SOR # (D) DELTTIME THE TIME REQUIRED TO TRAVERSE DELTA R WHEN # TRAVELING AT A VELOCITY EQUAL TO THE HORIZONTAL # VELOCITY OF THE PASSIVE VEHICLE - SAVED FROM # SOI PHASE # (E) TINT TIME OF INTERCEPT (SOI) - SAVED FROM SOI PHASE # # OUTPUT # # (1) TRKMKCNT NUMBER OF MARKS # (2) TTOGO TIME TO GO # (3) +MGA MIDDLE GIMBAL ANGLE # Page 724 # (4) DSPTEM1 TIME OF INTERCEPT OF PASSIVE VEHICLE ORBIT # (FOR SOI ONLY) # (5) POSTTPI PERIGEE ALTITUDE OF ACTIVE VEHICLE ORBIT AFTER # THE SOI (SOR) MANEUVER # (6) DELVTPI MAGNITUDE OF DELTA V AT SOI (SOR) TIME # (7) DELVTPF MAGNITUDE OF DELTA V AT INTERCEPT TIME # (8) DELVLVC DELTA VELOCITY AT SOI (AND SOR) - LOCAL VERTICAL # COORDINATES # # SUBROUTINE USED # # AVFLAGA # AVFLAGP # VNDSPLY # BANKCALL # GOFLASHR # GOTOPOOH # BLANKET # ENDOFJOB # PREC/TT # SELECTMU # INTRPVP # MAINRTNE
BANK04 SETLOC STBLEORB BANK
EBANK= SUBEXIT COUNT* $$/P3879
P38 TC BANKCALL CADR AVFLAGA # THIS VEHICLE ACTIVE TC +3
P78 TC BANKCALL CADR AVFLAGP # OTHER VEHICLE ACTIVE TC BANKCALL CADR P20FLGON # SET UPDATFLG, TRACKFLG CAF DECTWO TS NN CAF V06N33SR # DISPLAY TIG TC VNDSPLY CAF V06N55SR # DISPLAY CENTANG
TCR BANKCALL CADR GOFLASHR TCF GOTOPOOH # TERMINATE TCF +5# PROCEED TCF -5# RECYCLE CAF THREE # IMMEDIATE RETURN - BLANK R1, R2
TCR BLANKET # Page 725 TCF ENDOFJOB CAF FIVE TS OPTION1 CAF ONE TS OPTION2 # OPTION CODE IS SET TO 1 CAF V04N06SR # DISPLAY OPTION CODE - 1 = SOI, 2 = SOR
TCR BANKCALL CADR GOFLASHR TCF GOTOPOOH # TERMINATE TCF +5# PROCEED TCF -5# RECYCLE CAF BIT3 # IMMEDIATE RETURN - BLANK R3
TCR BLANKET TCF ENDOFJOB TC INTPRET SLOAD SR1
OPTION2
BHIZ DLOAD
OPTN1
TINT STORE TINTSOI # STORE FOR SOR PHASE
CLRGO
OPTNSW # OPTNSW: ON = SOI, OFF = SOR
JUNCTN1
OPTN1 SET CLEAR # SOI
OPTNSW
UPDATFLG CALL
PREC/TT
DAD SET
TIG
UPDATFLG STORE TINT # TI = TIG + TF EXIT CAF V06N57SR # DISPLAY DELTA R
TCR BANKCALL CADR GOFLASHR TCF GOTOPOOH # TERMINATE TCF +5# PROCEED TCF -5# RECYCLE CAF SIX # IMMEDIATE RETURN - BLANK R2, R3
TCR BLANKET TCF ENDOFJOB
+5EXTEND DCA TINT DXCH DSPTEM1 # FOR DISPLAY CAF V06N34SR # DISPLAY TIME OF INTERCEPT TC VNDSPLY TC INTPRET
JUNCTN1 CLEAR CALL # Page 726
P39/79SW
SELECTMU # SELECT MU, CLEAR FINALFLG, GO TO VN1645
RECYCLE CALL
PREC/TT
BOFF DLOAD
OPTNSW
OPTN2
TINT
STCALL TDEC1 # PRECISION UPDATE PASSIVE VEHICLE TO
INTRPVP # INTERCEPT TIME
VLOAD UNIT
RATT # RP/(RP)
PDVL VXV
VATT
ABVAL NORM # (VP X RP/(RP))
X1
PDDL DDV
DELTAR
SL* # DELTA R / (VP X RP/RP) 0 -7,1
STCALL DELTTIME # DELTA T = (RP) DELTA R / (VP X RP)
JUNCTN2
OPTN2 DLOAD DAD
TINTSOI
T STORE TINT # TI = TI + TF
JUNCTN2 DLOAD DSU
TINT
DELTTIME STORE TARGTIME # TT = TI - DELTA T
MAINRTNE STCALL TDEC1 # PRECISION UPDATE PASSIVE VEHICLE TO
INTRPVP # TARGET TIME DLOAD
TIG STORE INTIME
SSP VLOAD
SUBEXIT
TEST3979 # Page 727
RATT CALL
S3435.25
TEST3979 BOFF BON
P39/79SW
MAINRTN1
FINALFLG
P39P79
SET
UPDATFLG
P39P79 EXIT TC DSPLY81 # FOR P39 AND P79
MAINRTN1 VLOAD ABVAL
DELVEET3 STOVL DELVTPI # DELTA V
VPASS4
VSU ABVAL
VTPRIME STOVL DELVTPF # DELTA V (FINAL) = V'T - VT
RACT3
PDVL CALL
VIPRIME
PERIAPO1 # GET PERIGEE ALTITUDE CALL
SHIFTR1 STORE POSTTPI
BON SET
FINALFLG
DSPLY58
UPDATFLG
DSPLY58 EXIT CAF V06N58SR # DISPLAY HP, DELTA V, DELTA V (FINAL) TC VNDSPLY
DSPLY81 CAF V06N81SR # DISPLAY DELTA V (LV) TC VNDSPLY TC INTPRET
CLEAR VLOAD
XDELVFLG
DELVEET3
STCALL DELVSIN
VN1645 # DISPLAY TRKMKCNT, TTOGO, +MGA
BON GOTO
P39/79SW
P39/P79B
RECYCLE
# STABLE ORBIT MIDCOURSE PROGRAM (P39 AND P79) # # MOD NO -1 LOG SECTION - STABLE ORBIT - P38-P39 # MOD BY RUDNICKI.S DATE 25JAN68 # # Page 728 # FUNCTIONAL DESCRIPTION # # P39 AND P79 CALCULATE THE REQUIRED DELTA V AND OTHER INITIAL # CONDITIONS REQUIRED BY THE AGC TO MAKE A MIDCOURSE CORRECTION # MANEUVER AFTER COMPLETING THE SOI MANEUVER BUT BEFORE MAKING # THE SOR MANEUVER. # # CALLING SEQUENCE # # ASTRONAUT REQUEST THRU DSKY # # V37E39E IF THIS VEHICLE IS ACTIVE VEHICLE # V37E79E IF OTHER VEHICLE IS ACTIVE VEHICLE # # INPUT # # (1) TPASS4 TIME OF INTERCEPT - SAVED FROM P38/P78 # (2) TARGTIME TIME THAT PASSIVE VEHICLE IS AT INTERCEPT POINT - # SAVED FROM P38/P78 # # OUTPUT # # (1) TRKMKCNT NUMBER OF MARKS. # (2) TTOGO TIME TO GO # (3) +MGA MIDDLE GIMBAL ANGLE # (4) DELVLVC DELTA VELOCITY AT MID - LOCAL VERTICAL COORDINATES # # SUBROUTINES USED # # AVFLAGA # AVFLAGP # LOADTIME # SELECTMU # PRECSET # S34/35.1 # MAINRTNE
P39 TC BANKCALL CADR AVFLAGA # THIS VEHICLE ACTIVE EXTEND DCA ATIGINC TC P39/P79A
P79 TC BANKCALL CADR AVFLAGP # OTHER VEHICLE ACTIVE EXTEND DCA PTIGINC
P39/P79A DXCH KT # TIME TO PREPARE FOR BURN TC BANKCALL CADR P20FLGON # SET UPDATFLG, TRACKFLG TC INTPRET # Page 729
SET CALL
P39/79SW
SELECTMU # SELECT MU, CLEAR FINALFLG, GO TO VN1645
P39/P79B RTB DAD
LOADTIME
KT STORE TIG # TIG = T (PRESENT) + PREPARATION TIME
STCALL TDEC1 # PRECISION UPDATE ACTIVE AND PASSIVE
PRECSET # VEHICLES TO TIG CALL
S34/35.1# GET UNIT NORMAL DLOAD GOTO
TARGTIME
MAINRTNE # CALCULATE DELTA V AND DELTA V (LV)
PREC/TT STQ DLOAD
RTRN
TIG
STCALL TDEC1 # PRECISION UPDATE ACTIVE AND PASSIVE
PRECSET # VEHICLES TO TIG
VLOAD VSR*
RPASS3 0,2 STODL RVEC
CENTANG PUSH COS STODL CSTH
SIN SET
RVSW STOVL SNTH
VPASS3
VSR* 0,2
STCALL VVEC # GET TRANSFER TIME BASED ON CENTANG OF
TIMETHET # PASSIVE VEHICLE CALL
S34/35.1# GET UNIT NORMAL DLOAD GOTO
T
RTRN
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