BFR

from visual import *
a = vector(0.0,0.0,0.0)
v = vector(0.0,0.0,0.0)
s = vector(0.0,0.0,0.0)
g = -9.8
L1 = 106#length of total rocket
L2 = 48#length of rocket after thruster detatches
m1 = 85000#Mass of rocket
m2 = 1100000#mass of rocket and propellent
r = 4.5 #radius of rocket
A =2*pi*r*L1+2*pi*r**2
cD = .75#NASA.gov drag coefficient
Ft = vector(0.0,0.0,0.0)#Force of the thrusters
Fg = vector(0.0,0.0,0.0)#Force of gravity
Fd = vector(0.0,0.0,0.0)#Force of drag
G = 6.67e-11#gravitational constant
M = 6e24#mass of the Earth
t = 0.0
dt = 5.0
BFR = cylinder(radius = r,height = L1, color=color.cyan)


while s.y<2000000.0:#Low Earth orbit is 2000km and the BFR goes that high to avoid the atmosphere
    rate = (10000)
    lm = (m2+m1)/(t+dt)
    p = (0.289*e**(1.73-.000157*mag(s)))#equation for the change in the density of the air.
    Ft = vector(0.0,52700000.0,0.0)
    Fg = vector(0.0,(m2+m1*g),0.0)
    Fd = vector(0.0,.5*A*cD*p*mag(v)**2,0.0)
    Fnet = Ft-(Fd+(Fg))
    a = Fnet/(lm)
    v = v + a * dt
    s = s + v * dt
    BFR.pos = s
    t = t + dt
    print 't=',t
#I have chosen to have the BFR fly from Sydney to Singapore.
#So if the rocket shoots relatively straight up, it will have to fly about 6300km.
#Though since we're in Low Earth Orbit we can get rid of drag due to the lack of atmosphere.
#Half way through the thruster will detach from our rocket, leaving us with L2.

while s.x<6000000.0:
    rate = (10000)
    Ft = vector(52700000.0,0.0,0.0)
    Fg = vector(0.0,(m1+m2)*g,0.0)
    Fnet = Ft-Fg
    a = Fnet/(m1+m2)
    v = v + a * dt
    s = s + v * dt
    BFR.pos = s
    t = t + dt
    print 't=',t
while s.y>0.0:#Makes sure our rocket runs until it touches down.
    rate = (10000)
    lm = (m2+m1)/(t+dt)
    p = (0.289*e**(1.73-.000157*mag(s)))#equation for the change in the density of the air.
    Ft = vector(0.0,-52700000.0,0.0)
    Fg = vector(0.0,(m2+m1*g),0.0)
    Fd = vector(0.0,.5*A*cD*p*mag(v)**2,0.0)
    Fnet = Fg+(Ft)
    a = Fnet/(lm)
    v = v + a * dt
    s = s + v * dt
    BFR.pos = s
    t = t + dt
    print 't=',t
##The total time of our travel is just over 30 minutes which lines up with what SpaceX claims their time would be.