from tudatpy.kernel.simulation import environment_setup
from tudatpy.kernel.simulation import propagation_setup
# Define simulation time and step size
simulation_start_epoch = 0.0
simulation_end_epoch = constants.JULIAN_DAY
fixed_step_size = 100.0
# Load spice kernels.
spice_interface.load_standard_kernels()
# Create body objects
bodies_to_create = ["Sun"]
body_settings = environment_setup.get_default_body_settings(
bodies_to_create, simulation_start_epoch, simulation_end_epoch,
fixed_step_size)
bodies = environment_setup.create_bodies(body_settings)
# Create vehicle object
bodies["Apollo"] = environment_setup.Body()
# Set mass of vehicle
bodies["Apollo"].set_constant_body_mass(2000.0)
global_frame_origin = "SSB"
global_frame_orientation = "ECLIPJ2000"
environment_setup.set_global_frame_body_ephemerides(bodies,
global_frame_origin,
global_frame_orientation)
###########################################################################
# Set simulation start epoch
simulation_start_epoch = 0.0 # s
# Load spice kernels
spice_interface.load_standard_kernels()
# Define settings for celestial bodies
bodies_to_create = ['Moon']
# Define coordinate system
global_frame_origin = 'Moon'
global_frame_orientation = 'ECLIPJ2000'
# Create body settings
# N.B.: all the bodies added after this function is called will automatically
# be placed in the same reference frame, which is the same for the full
# system of bodies
body_settings = environment_setup.get_default_body_settings(
bodies_to_create, global_frame_origin, global_frame_orientation)
# Create bodies
bodies = environment_setup.create_system_of_bodies(body_settings)
###########################################################################
# CREATE VEHICLE ##########################################################
###########################################################################
# Create vehicle object and add it to the existing system of bodies
bodies.create_empty_body('Vehicle')
# Set mass of vehicle
bodies.get_body('Vehicle').set_constant_mass(vehicle_mass)
###########################################################################
# CREATE ACCELERATIONS ####################################################
###########################################################################
# Set vehicle thrust magnitude.
thrust_magnitude = 25.0
# Set vehicle specific impulse.
specific_impulse = 5.0E3
################################################################################
# SETUP ENVIRONMENT ############################################################
################################################################################
# Define bodies in simulation.
bodies_to_create = ["Sun", "Earth", "Moon"]
# Create bodies in simulation.
body_settings = environment_setup.get_default_body_settings(bodies_to_create)
body_system = environment_setup.create_bodies(body_settings)
environment_setup.set_global_frame_body_ephemerides(body_system, "SSB",
"ECLIPJ2000")
################################################################################
# SETUP ENVIRONMENT : CREATE VEHICLE ###########################################
################################################################################
body_system["Vehicle"] = environment_setup.Body()
body_system["Vehicle"].set_constant_body_mass(vehicle_mass)
################################################################################
# SETUP ENVIRONMENT : FINALIZE BODY CREATION ###################################
################################################################################
SC_NAMES = []
for i in range(0, number_RAAN):
SC_NAMES.append('CHESS' +
str(RAAN[i])) # creates the name of each spacecraft
# Simulation Setup
spice_interface.load_standard_kernels()
simulation_start_epoch = 631108800.0
simulation_end_epoch = 631126800.0
# Bodies
bodies_to_create = ["Earth", "Sun"]
body_settings = environment_setup.get_default_body_settings(
bodies_to_create, simulation_start_epoch, simulation_end_epoch, "Earth",
"J2000")
bodies = environment_setup.create_system_of_bodies(body_settings)
reference_area_radiation = 0.1159
radiation_pressure_coefficient = 1.2
occulting_bodies = ["Earth"]
radiation_pressure_settings = environment_setup.radiation_pressure.cannonball(
"Sun", reference_area_radiation, radiation_pressure_coefficient,
occulting_bodies)
central_bodies = []
bodies_to_propagate = SC_NAMES
def create_simulation_bodies(
itokawa_radius: float
) -> tudatpy.kernel.simulation.environment_setup.SystemOfBodies:
"""
It creates all the body settings and body objects required by the simulation.
Parameters
----------
itokawa_radius : float
Radius of Itokawa, assuming a spherical shape.
Returns
-------
tudatpy.kernel.simulation.environment_setup.SystemOfBodies
System of bodies to be used in the simulation.
"""
### CELESTIAL BODIES ###
# Define Itokawa body frame name
itokawa_body_frame_name = "Itokawa_Frame"
# Create default body settings for selected celestial bodies
bodies_to_create = ["Sun", "Earth", "Jupiter", "Saturn", "Mars"]
# Create default body settings for bodies_to_create, with "Earth"/"J2000" as
# global frame origin and orientation. This environment will only be valid
# in the indicated time range [simulation_start_epoch --- simulation_end_epoch]
body_settings = environment_setup.get_default_body_settings(
bodies_to_create, "SSB", "ECLIPJ2000")
# Add Itokawa body
body_settings.add_empty_settings("Itokawa")
# Gravity field definition
itokawa_gravity_field_settings = get_itokawa_gravity_field_settings(
itokawa_body_frame_name, itokawa_radius)
# Adds Itokawa settings
# Gravity field
body_settings.get(
"Itokawa").gravity_field_settings = itokawa_gravity_field_settings
# Rotational model
body_settings.get(
"Itokawa").rotation_model_settings = get_itokawa_rotation_settings(
itokawa_body_frame_name)
# Ephemeris
body_settings.get(
"Itokawa").ephemeris_settings = get_itokawa_ephemeris_settings(
itokawa_gravity_field_settings.gravitational_parameter)
# Shape (spherical)
body_settings.get("Itokawa").shape_settings = get_itokawa_shape_settings(
itokawa_radius)
# Create system of selected bodies
bodies = environment_setup.create_system_of_bodies(body_settings)
### VEHICLE BODY ###
# Create vehicle object
bodies.create_empty_body("Spacecraft")
bodies.get_body("Spacecraft").set_constant_mass(400.0)
# Create radiation pressure settings, and add to vehicle
reference_area_radiation = 4.0
radiation_pressure_coefficient = 1.2
radiation_pressure_settings = environment_setup.radiation_pressure.cannonball(
"Sun", reference_area_radiation, radiation_pressure_coefficient)
environment_setup.add_radiation_pressure_interface(
bodies, "Spacecraft", radiation_pressure_settings)
return bodies
