from math import pi, exp
from vector import Vector
from simulation import AerobreakingSimulation
from body import ShapedBody
from universal_constants import MARS_RADIUS, MARS_RADIUS2
from universal_functions import mars_orbital_velocity
from forces import f_gravity
from plots import mars_xys
import pylab
RADIUS_0 = 100000 + MARS_RADIUS # [m]
POSITION_0 = Vector(RADIUS_0, 0, 0) # [m]
VELOCITY_0 = Vector(0, mars_orbital_velocity(RADIUS_0), 0) # [m]
MASS_MODULE = 25000 # [kg]
MASS_PROBE = 17 # [kg]
MARS_H_REF = 11000.0 # [m]
MARS_DENSITY_0 = 0.02 # [?]
variation = 1 # [%]
MARS_DENSITY_HIGH = MARS_DENSITY_0 * (100 + variation) / 100
MARS_DENSITY_LOW = MARS_DENSITY_0 * (100 - variation) / 100
for MARS_DENSITY in (MARS_DENSITY_LOW, MARS_DENSITY_0, MARS_DENSITY_HIGH):
def d(r):
return MARS_DENSITY * exp(-(r - MARS_RADIUS) / MARS_H_REF)
def f_drag(b):
return - b.direction * d(b.radius) * b.area * b.c_drag * b.speed2 / 2
from universal_constants import MARS_RADIUS, MARS_RADIUS2
from universal_functions import mars_orbital_velocity
# Constants
DURATION = 1000
dt = 1
def free_flight(body, t, dt, condition=lambda b: b.radius2 < MARS_RADIUS2):
simulation = Simulation(body, f_drag + f_gravity)
simulation.run(t, dt=dt, condition=condition)
return simulation
for altitude in (100000, 200000, 300000, 400000):
POSITION_0 = Vector(MARS_RADIUS + altitude, 0)
VELOCITY_0 = mars_orbital_velocity(MARS_RADIUS + altitude) * Vector(0, 1)
body = ShapedBody(POSITION_0,
VELOCITY_0,
mass=20000.0,
area=pi * 2.5 ** 2,
c_drag=0.3,
r_nose=1.5)
p = free_flight(body, t=DURATION, dt=dt)
vr = (p.rs[-1] - p.rs[0]) / p.duration
print("For altitude: " + str(altitude) + " m")
print("Delta radius: " + str(p.rs[-1] - p.rs[0]) + " m")
print("Radial speed: " + str(vr) + " m/s")
