Listing 4 

Save a copy of your working Apollo11.bas (Listing 2). Call
it, say, Apoleorb.bas.   NOW EXTEND Apollo11.bas AS BELOW.
Line 16 - becomes  -    apogee = 547460
Two pairs of lines - 'IF colour = 1 THEN' and 'END IF' can
be deleted (near line 21 and in CASE 2), but do retain the
included lines.
We don't want lines 53 - 55 after Sector 3, so put inside
an  IF....END IF,    as follows -
 IF Sector < 4 THEN
  tp = t - 29000              'x axis position to plot....
  PSET (tp, 7500 + E * 500), 4     '...total energy and...
  PSET (tp, w * 4000 - 38000), 2              '...velocity
 END IF 
   'CASE 3 NOW NEEDS TO BE MODIFIED TO SET UP FOR CASE 4.
  CASE 3:        'COASTING AFTER TLI BURN
   IF t MOD 60 = 0 THEN      'each minute, print on screen
    LOCATE 24:PRINT hr;"h"; min;"m,   "; w; 'NOTE last ";"
    PRINT "km / sec        "; de; " km radius":
    IF tm = 190 THEN              'end Sector 3 at 190 min
     CALL Tidyup    'rearrangement of Apollo configuration
     Sector = 4: ti = 5       'now 5 second time intervals
     xm50 = 250000: ym50 = -188000: olddm = dm
       'NOW CHANGE to earth/ moon region WINDOW
     WINDOW (-10000, 12000)-(390000, -288000): CLS
     LINE (-10000, 12000)-(390000, -288000), 15, B
     FOR yc = -180000 TO -120000 STEP 20000 'energy -units
             LINE (0, yc)-(9000, yc), 4: NEXT
     FOR yc = -180000 TO -120000 STEP 2000 'energy -tenths
             LINE (0, yc)-(4000, yc), 4: NEXT: COLOR 4
     FOR n = -2 TO 0: LOCATE 14 - n * 2, 5: PRINT n: NEXT
     LOCATE 20, 6: PRINT "ENERGY": COLOR 15
     FOR yc = -270000 TO -190000 STEP 20000
                         LINE (0, yc)-(4000, yc), 15: NEXT
     LOCATE 25, 5: PRINT "ALTITUDE"
     LOCATE 21, 6: PRINT "500": LOCATE 29, 6: PRINT "100";
    END IF
   END IF
         ' NOW add CASE 4, CASE 5, CASE 6 and CASE 7
  CASE 4:   'TRIP TO MOON
   IF tm MOD 60 = 0 AND min = 0 THEN 'each hour, mark time
    LOCATE 1, 5: PRINT hr; "hrs,"; dm; "kms from moon.";
    PRINT " Velocity"; w; "km/sec"
    IF hr < 70 THEN LINE (x, y)-STEP(0, 3000), 15
    IF hr MOD 10 = 0 THEN                  'every 10 hours
     LINE (x, y)-STEP(0, 8000), 15        'mark time scale
     LOCATE (-y + 3000) / 10000, x / 5000: PRINT hr
     IF hr = 70 THEN            'draw enlarged (50 X) moon
      CIRCLE (xm50, ym50), Mrad * 50, 2 'and illuminate it
      xt = Mrad * 50 * COS(.1): yt = Mrad * 50 * SIN(.1)
      LINE (xm50 - xt, ym50 - yt)-(xm50 + xt, ym50 + yt),2
      PAINT (xm50, ym50 - 2000), 2, 2
     END IF   'hr = 70
    END IF    'each 10 hours
   END IF     'each hour
   IF hr > 73 THEN
    IF t MOD 60=0 THEN PSET(xm50+(x-xm)*50,ym50+(y-ym)*50)
    PSET ((tm-4380)*300, (dm-Mrad)*200 -290000),15    'alt
    PSET ((tm -4380) *300, (E -6) * 20000), 4 'plot energy
    IF olddm - dm < 1.6 THEN      'rate < 1.6 km in 5 secs
     COLOR 4: LOCATE 2, 5         'time for first LOI burn
     PRINT "(a)Start LOI 1,"; INT(dm - Mrad); "km alt.";
     ti = 1                    'change to 1 sec. intervals
     SI = 310: th = 9318: thr = th * .0098: ff = th / SI
     m = 43750: Sector = 5: loi1 = 1: te = t + 340
     LINE (xm50, ym50)-STEP((x -xm) * 50, (y -ym) * 50), 4
     LINE -STEP(10000, 0), 4: LOCATE 24, 73: PRINT "(a)"
    END IF      'approach rate < 1.6/5
    olddm = dm          'remember old dm for rate checking
   END IF       'hr > 73
  CASE 5:   'INTO MOON ORBIT
   h = dm - Mrad                                 'altitude
   IF t MOD 60 = 0 THEN ......
   ..PSET (xm50 + (x - xm) * 50, ym50 + (y - ym) * 50), 15
   PSET ((tm -4380) * 300, (E -6) * 20000), 4 'plot energy
   PSET ((tm - 4380) * 300, h * 200 -290000), 15 'altitude
   IF loi1 = 1 THEN                'LOI 1 burn in progress
    LINE (xm50, ym50)-STEP((x - xm) * 50, (y - ym) * 50),4
    acc =thr/(m-ff/2): m =m -ff 'thrust accel. & fuel burn
    ang=ATN((ym-y)/(x -xm)) 'angle, moon surface to y axis
    atx=acc*SIN(ang): aty=acc*COS(ang)  'accel. components
    IF t = te THEN                      'end of LOI 1 burn
     LINE -STEP(10000, 0), 4: loi1 = 2: atx = 0: aty = 0
     LOCATE 27, 69: PRINT "(b)": LOCATE 2, 40
     PRINT"(b)Burn 340 sec using";INT(340 * ff); "kg fuel"
    END IF    't = te
   END IF     'loi1 = 1
   IF loi1 = 2 THEN               'coasting out to apolune
    IF dm < olddm - .06 THEN              'if past apolune
     LINE (xm50, ym50)-STEP((x-xm) *50, (y - ym) * 50), 15
     LINE -STEP(10000, 0), 4: LOCATE 14, 37: COLOR 15
     loi1 = 3: PRINT "(c)"; CINT(h); "km": LOCATE 3, 5
     PRINT "(c)Apolune ="; INT(dm); ", alt. ="; CINT(h)
    END IF    'past apolune
   END IF     'loi1 = 2
   IF loi1 = 3 THEN               'coasting in to perilune
    IF dm - olddm > .05 THEN                'past perilune
     COLOR 12: LOCATE 3, 40
     PRINT "(d)Perilune ="; CINT(dm); ", alt. ="; INT(h)
     LINE (xm50, ym50)-STEP((x-xm) *50, (y - ym) * 50), 12
     LINE -STEP(10000,0),12: LOCATE 25,71: PRINT "(d)&(e)"
     Sector = 6: ' DO: LOOP WHILE INKEY$ = ""
     LOCATE 4,5:PRINT"(d)Start LOI 2,"; INT(h); "km alt.";
     loi2 = 1: te = t + 31: adj = -.15
    END IF     'past perilune
   END IF      'loi1 = 3
   olddm = dm                             'remember old dm 
  CASE 6:   'CIRCULARISING MOON ORBIT
   IF t MOD 60=0 THEN PSET(xm50+(x-xm)*50,ym50+(y-ym) *50)
   h = dm - Mrad                                 'altitude
   PSET ((tm - 4380) * 300, (E - 6) *20000),4 'plot energy
   PSET ((tm - 4380) * 300, h * 200 - 290000),15 'altitude
   IF loi2 = 1 THEN                 'LOI 2 burn continuing
    acc =thr/(m-ff/2): m=m - ff 'thrust accel. & fuel burn
    ang=ATN((ym-y)/(x-xm))+adj'angle, moon surf. to y axis
    atx=acc*SIN(ang): aty=acc* COS(ang) 'accel. components
    LINE(xm50,ym50)-STEP((x-xm)*50,(y-ym)* 50), 12 'radial
    IF t > te THEN                    'LOI 2 burn finished
     LINE-STEP(10000,0),12:m=m+ff:loi2=2: atx = 0: aty = 0
     t1=t+1800:t2=t+3600:t3=t+5400:t4=t+7200: LOCATE 4, 40
   PRINT "(e)Burn 31 secs, using"; INT(31 * ff); "kg fuel"
     COLOR 15
    END IF   't > te
   END IF    'loi2 = 1
   IF loi2 = 2 THEN        'coasting around circular orbit
    IF t = t1 OR t = t2 OR t = t3 OR t = t4 THEN
     IF t = t1 THEN LOCATE 28, 46
     IF t = t2 THEN LOCATE 15, 43
     IF t = t3 THEN LOCATE 13, 67
     IF t = t4 THEN LOCATE 26, 71
     LINE (xm50,ym50)-STEP((x-xm) * 50, (y - ym) * 50), 15
     LINE -STEP(20000, 0): PRINT INT(h); "km"
     IF t = t4 THEN Sector = 7
    END IF
   END IF 
  CASE 7:          'MORE MOON ORBITS AND DESCENT
   IF t = 370400 THEN       'start descent burn of 10 secs
    COLOR 15: LOCATE 10, 72: PRINT "(f)": LOCATE 5, 5
    PRINT "(f)13 orbits shown by cycloidal 'pigtail' before
           LEM leaves at ..."
    mlem = 14841: tl = 4455 * .72: thr = tl * .0098
    SIl = 310: ff = tl / SIl: doi = 1: te = t + 10
    'DO: LOOP WHILE INKEY$ = ""
   END IF
   IF doi = 1 THEN           'Descent Orbit Injection burn
    LINE (xm50,ym50)-STEP((x-xm)*50, (y-ym)*50),14 'radial
    acc =thr/(mlem-ff/2): mlem=mlem-ff 'accel. & fuel burn
    ang=ATN((ym-y)/(x- xm)) 'angle, moon surface to y axis
    atx=acc*SIN(ang): aty=acc* COS(ang) 'accel. components
    IF t = te THEN                  'end of LEM's DOI burn
     COLOR 14: LOCATE 17, 70: PRINT "(g)": LOCATE 6, 5
     PRINT "(g)DOI. 10 sec at 72% thrust," ;
     PRINT " 99 kg fuel, for perilune 16 km alt."
     doi = 2: atx = 0: aty = 0: tf = t + 3400
     'DO: LOOP WHILE INKEY$ = ""
    END IF
   END IF
   IF doi = 2 THEN           'LEM coasting to landing area
    PSET (xm50 + (x - xm) * 50, ym50 + (y - ym) * 50)', 14
    IF t = tf THEN    'finish with LEM 16 km above landing
     LINE -STEP(-10 00, 0)
     finish = 1: LOCATE 24, 31: PRINT "(h)": LOCATE 7, 5
     PRINT "(h)Landing Target. 30 deg. right of";
     COLOR 15: PRINT " centre of near face (j)."
     LOCATE 17, 32: PRINT "(j)"
   LINE(xm50,ym50)-STEP(-95000*COS(.35),95000*SIN(.35)),15
    END IF
   END IF
                 ' AND FINISH OFF WITH
  CASE ELSE
 END SELECT
LOOP UNTIL finish = 1: DO: LOOP WHILE INKEY$ = ""