Created
November 13, 2012 10:28
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Earth-Moon orbit simulator
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from math import * | |
#All distance units are in m, velocity in m/s | |
#Enter initial simulation data here | |
initial_x = -6.38E6 | |
initial_y = 12E6 | |
initial_vx = 1.1E4 #-6.38E6,12E6,1.1E4,3.5E3 | |
initial_vy = 3.5E3 | |
M = 50 #satellite mass | |
end_time = 10000 #This is how many seconds you want the simulation to go. | |
#Data about Earth and the Moon goes here: | |
Earth = [0.0,0.0] | |
Moon = [385E6,0] | |
mE = 6.0E24 | |
mM = 7.0E22 | |
rE = 6.38E6 | |
rM = 1.738E6 | |
G = 6.67E-11 | |
Fburn = 3850 #F = 3850, start 43080, end 43180 | |
startBurn = 43080 | |
endBurn = 43180 | |
#Simulation data goes here | |
t = 0 | |
delta_t = 1 | |
crashed = False | |
data = [] | |
data.append([initial_x,initial_y,initial_vx,initial_vy,crashed]) | |
i = 0 | |
def isBurnTime(startBurn,endBurn): | |
if(t>=startBurn and t<=endBurn): | |
return 1 | |
else: | |
return 0 | |
while (t<end_time and crashed == False): | |
isBurning = isBurnTime(startBurn,endBurn) | |
dE = sqrt((data[i][0] - Earth[0])**2+(data[i][1] - Earth[1])**2) | |
dM = sqrt((data[i][0] - Moon[0])**2+(data[i][1] - Moon[1])**2) | |
Fe = G*M*mE*1./(dE**2) | |
Fm = G*M*mM*1./(dM**2) | |
speed = sqrt(data[i][2]**2+data[i][3]**2) | |
accel_x = 1./M*(-1*Fe*(data[i][0]-Earth[0])*1./dE -Fm*(data[i][0]-Moon[0])*1./dM - isBurning*Fburn*data[i][2]*1./speed) | |
accel_y = 1./M*(-1*Fe*(data[i][1]-Earth[1])*1./dE -Fm*(data[i][1]-Moon[1])*1./dM - isBurning*Fburn*data[i][3]*1./speed) | |
v_x = data[i][2]+accel_x*delta_t | |
v_y = data[i][3]+accel_y*delta_t | |
x = data[i][0]+ data[i][2]*delta_t+0.5*accel_x*delta_t**2 | |
y = data[i][1] + data[i][3]*delta_t + 0.5*accel_y*delta_t**2 | |
if(dE<rE or dM<rM): | |
crashed = True | |
print "Crash!" | |
data.append([x,y,v_x,v_y,crashed]) | |
i = i + 1 | |
t+=delta_t | |
print "Completed calculations." | |
outFile = open('output.txt','w') | |
time_int = 600 | |
count = 0 | |
for row in data: | |
count+=1 | |
if(count>=time_int): | |
count = 0 | |
new_x = row[0]*1./(1.0E6) | |
new_y = row[1]*1./(1.0E6) | |
output = str(new_x)+','+str(new_y)+'\n' | |
outFile.write(output) | |
outFile.close() | |
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