# ISC License
#
# Copyright (c) 2024, Autonomous Vehicle Systems Lab, University of Colorado at Boulder
#
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#
r"""
Overview
--------
This script sets up a 3-DOF spacecraft that is operating near-Halo orbit at L2 Earth-Moon Lagrange points. The purpose
is to illustrate how to set up the spacecraft's initial conditions to create a near-Halo orbit and convert the barycenter focused
non-dimensional ICs to earth-centered inertial frame components.
The script is found in the folder ``basilisk/examples`` and executed by using::
python3 scenarioHaloOrbit.py
For this simulation, the Earth is assumed stationary, and the Moon's trajectory is generated using SPICE. Refer to
:ref:`scenarioOrbitMultiBody` to learn how to create multiple gravity bodies and read a SPICE trajectory.
When the simulation completes, three plots are shown. The first plot shows the orbits of the Moon and spacecraft in
the Earth-centered inertial frame. The second and third plots show the motion of the spacecraft in a frame rotating
with the Moon. In the second plot, the y-axis represents the Moon's velocity direction, and in the third plot, the
y-axis represents the cross product of the Moon's position vector and velocity vector.
Illustration of Simulation Results
----------------------------------
The following images illustrate the simulation run results with the following settings:
::
showPlots = True
.. image:: /_images/Scenarios/scenarioHaloOrbitFig1.svg
:align: center
.. image:: /_images/Scenarios/scenarioHaloOrbitFig2.svg
:align: center
.. image:: /_images/Scenarios/scenarioHaloOrbitFig3.svg
:align: center
"""
#
# Basilisk Scenario Script and Integrated Test
#
# Purpose: This scenario illustrates the near-Halo orbit of a spacecraft.
# Author: Yumeka Nagano
# Creation Date: Feb. 12, 2024
#
import os
from datetime import datetime
import matplotlib.pyplot as plt
import numpy as np
from Basilisk import __path__
from Basilisk.simulation import spacecraft
from Basilisk.topLevelModules import pyswice
from Basilisk.utilities import (SimulationBaseClass, macros, orbitalMotion,
simIncludeGravBody, unitTestSupport, vizSupport)
from Basilisk.utilities.pyswice_spk_utilities import spkRead
bskPath = __path__[0]
fileName = os.path.basename(os.path.splitext(__file__)[0])
[docs]def run(showPlots=True):
"""
Args:
showPlots (bool): Determines if the script should display plots
"""
# Create simulation variable names
simTaskName = "dynTask"
simProcessName = "dynProcess"
# Create a sim module as an empty container
scSim = SimulationBaseClass.SimBaseClass()
scSim.SetProgressBar(True)
# Create the simulation process (dynamics)
dynProcess = scSim.CreateNewProcess(simProcessName)
# Add the dynamics task to the dynamics process and specify the integration update time
timestep = 300
simulationTimeStep = macros.sec2nano(timestep)
dynProcess.addTask(scSim.CreateNewTask(simTaskName, simulationTimeStep))
# Setup the spacecraft object
scObject = spacecraft.Spacecraft()
scObject.ModelTag = "HaloSat"
# Add spacecraft object to the simulation process
# Make this model a lower priority than the SPICE object task
scSim.AddModelToTask(simTaskName, scObject, 0)
# Setup gravity factory and gravity bodies
# Include bodies as a list of SPICE names
gravFactory = simIncludeGravBody.gravBodyFactory()
gravBodies = gravFactory.createBodies('moon', 'earth')
gravBodies['earth'].isCentralBody = True
# Add gravity bodies to the spacecraft dynamics
gravFactory.addBodiesTo(scObject)
# Create default SPICE module, specify start date/time.
timeInitString = "2022 August 31 15:00:00.0"
bsk_path = __path__[0]
spiceObject = gravFactory.createSpiceInterface(bsk_path + "/supportData/EphemerisData/", time=timeInitString,
epochInMsg=True)
spiceObject.zeroBase = 'earth'
# Add SPICE object to the simulation task list
scSim.AddModelToTask(simTaskName, spiceObject, 1)
# Import SPICE ephemeris data into the python environment
pyswice.furnsh_c(spiceObject.SPICEDataPath + 'de430.bsp') # solar system bodies
pyswice.furnsh_c(spiceObject.SPICEDataPath + 'naif0012.tls') # leap second file
pyswice.furnsh_c(spiceObject.SPICEDataPath + 'de-403-masses.tpc') # solar system masses
pyswice.furnsh_c(spiceObject.SPICEDataPath + 'pck00010.tpc') # generic Planetary Constants Kernel
# Set spacecraft ICs
# Get initial moon data
moonSpiceName = 'moon'
moonInitialState = 1000 * spkRead(moonSpiceName, timeInitString, 'J2000', 'earth')
moon_rN_init = moonInitialState[0:3]
moon_vN_init = moonInitialState[3:6]
moon = gravBodies['moon']
earth = gravBodies['earth']
oe = orbitalMotion.rv2elem(earth.mu, moon_rN_init, moon_vN_init)
moon_a = oe.a
# Direction Cosine Matrix (DCM) from earth centered inertial frame to earth-moon rotation frame
DCMInit = np.array([moon_rN_init/np.linalg.norm(moon_rN_init),moon_vN_init/np.linalg.norm(moon_vN_init),
np.cross(moon_rN_init, moon_vN_init) / np.linalg.norm(np.cross(moon_rN_init, moon_vN_init))])
# Set up non-dimensional parameters
T_ND = np.sqrt(moon_a ** 3 / (earth.mu + moon.mu)) # non-dimensional time for one second
mu_ND = moon.mu/(earth.mu + moon.mu) # non-dimensional mass
# Set up initial conditions for the spacecraft
x0 = 1.182212 * moon_a + moon_a * mu_ND
z0 = 0.049 * moon_a
dy0 = -0.167 * moon_a / T_ND
X0 = np.array([[x0], [0], [z0]])
dX0 = np.array([[0], [np.linalg.norm(moon_vN_init) + dy0], [0]])
rN = np.dot(np.transpose(DCMInit), X0)
vN = np.dot(np.transpose(DCMInit), dX0)
scObject.hub.r_CN_NInit = rN
scObject.hub.v_CN_NInit = vN
# Set simulation time
simulationTime = macros.day2nano(17.5)
# Setup data logging
numDataPoints = 1000
samplingTime = unitTestSupport.samplingTime(simulationTime, simulationTimeStep, numDataPoints)
# Setup spacecraft data recorder
scDataRec = scObject.scStateOutMsg.recorder(samplingTime)
MoonDataRec = spiceObject.planetStateOutMsgs[0].recorder(samplingTime)
scSim.AddModelToTask(simTaskName, scDataRec)
scSim.AddModelToTask(simTaskName, MoonDataRec)
viz = vizSupport.enableUnityVisualization(scSim, simTaskName, scObject,
# saveFile=__file__
)
# Initialize simulation
scSim.InitializeSimulation()
# Execute simulation
scSim.ConfigureStopTime(simulationTime)
scSim.ExecuteSimulation()
# Retrieve logged data
posData = scDataRec.r_BN_N
velData = scDataRec.v_BN_N
timeData = scDataRec.times()
moonPos = MoonDataRec.PositionVector
moonVel = MoonDataRec.VelocityVector
# Plot results
np.set_printoptions(precision=16)
plt.close("all")
figureList = {}
b = oe.a * np.sqrt(1 - oe.e * oe.e)
# First plot: Draw orbit in inertial frame
fig = plt.figure(1, figsize=np.array((1.0, b / oe.a)) * 4.75, dpi=100)
plt.axis(np.array([-oe.rApoap, oe.rPeriap, -b, b]) / 1000 * 1.25)
ax = fig.gca()
ax.ticklabel_format(style='scientific', scilimits=[-5, 3])
# Draw 'cartoon' Earth
ax.add_artist(plt.Circle((0, 0), 0.2e5, color='b'))
# Plot spacecraft orbit data
rDataSpacecraft = []
fDataSpacecraft = []
for ii in range(len(posData)):
oeDataSpacecraft = orbitalMotion.rv2elem(earth.mu, posData[ii], velData[ii])
rDataSpacecraft.append(oeDataSpacecraft.rmag)
fDataSpacecraft.append(oeDataSpacecraft.f + oeDataSpacecraft.omega - oe.omega)
plt.plot(rDataSpacecraft * np.cos(fDataSpacecraft) / 1000, rDataSpacecraft * np.sin(fDataSpacecraft) / 1000,
color='g', linewidth=3.0, label='Spacecraft')
# Plot moon orbit data
rDataMoon = []
fDataMoon = []
for ii in range(len(timeData)):
oeDataMoon = orbitalMotion.rv2elem(earth.mu, moonPos[ii], moonVel[ii])
rDataMoon.append(oeDataMoon.rmag)
fDataMoon.append(oeDataMoon.f + oeDataMoon.omega - oe.omega)
plt.plot(rDataMoon * np.cos(fDataMoon) / 1000, rDataMoon * np.sin(fDataMoon) / 1000, color='0.5',
linewidth=3.0, label='Moon')
plt.xlabel(r'$i_e$ Coord. [km]')
plt.ylabel(r'$i_p$ Coord. [km]')
plt.grid()
plt.legend()
pltName = fileName + "Fig1"
figureList[pltName] = plt.figure(1)
# Second plot: Draw orbit in frame rotating with the Moon (the center is L2 point)
# x axis is moon position vector direction and y axis is moon velocity vector direction
fig = plt.figure(2, figsize=np.array((1.0, b / oe.a)) * 4.75, dpi=100)
plt.axis(np.array([-1e5, 5e5, -3e5, 3e5]) * 1.25)
ax = fig.gca()
ax.ticklabel_format(style='scientific', scilimits=[-5, 3])
# Draw 'cartoon' Earth
ax.add_artist(plt.Circle((0, 0), 0.2e5, color='b'))
# Plot spacecraft orbit data
rSpacecraft = np.zeros((len(posData), 3))
for ii in range(len(posData)):
# Get Moon position and velocity
moon_rN = moonPos[ii]
moon_vN = moonVel[ii]
# Direction Cosine Matrix (DCM) from earth centered inertial frame to earth-moon rotation frame
rSpacecraftMag = np.linalg.norm(posData[ii])
rMoonMag = np.linalg.norm(moon_rN)
DCM = [moon_rN / rMoonMag, moon_vN / np.linalg.norm(moon_vN),
np.cross(moon_rN, moon_vN) / np.linalg.norm(np.cross(moon_rN, moon_vN))]
# Spacecraft position in rotating frame
rSpacecraft[ii,:] = np.dot(DCM, posData[ii])
plt.plot(rSpacecraft[:,0] / 1000, rSpacecraft[:,1] / 1000,
color='g', linewidth=3.0, label='Spacecraft')
plt.xlabel('Earth-Moon axis [km]')
plt.ylabel('Moon Velocity axis [km]')
plt.grid()
plt.legend()
pltName = fileName + "Fig2"
figureList[pltName] = plt.figure(2)
# Third plot: Draw orbit in frame rotating with the Moon (the center is L2 point)
# x axis is moon position vector direction and y axis is the cross product direction of the moon position vector and
# velocity vector
fig = plt.figure(3, figsize=np.array((1.0, b / oe.a)) * 4.75, dpi=100)
plt.axis(np.array([-1e5, 5e5, -3e5, 3e5]) * 1.25)
ax = fig.gca()
ax.ticklabel_format(style='scientific', scilimits=[-5, 3])
# Draw 'cartoon' Earth
ax.add_artist(plt.Circle((0, 0), 0.2e5, color='b'))
plt.plot(rSpacecraft[:, 0] / 1000, rSpacecraft[:, 2] / 1000,
color='g', linewidth=3.0, label='Spacecraft')
plt.xlabel('Earth-Moon axis [km]')
plt.ylabel('Earth-Moon perpendicular axis [km]')
plt.grid()
plt.legend()
pltName = fileName + "Fig3"
figureList[pltName] = plt.figure(3)
if showPlots:
plt.show()
plt.close("all")
# Unload spice libraries
gravFactory.unloadSpiceKernels()
pyswice.unload_c(spiceObject.SPICEDataPath + 'de430.bsp') # solar system bodies
pyswice.unload_c(spiceObject.SPICEDataPath + 'naif0012.tls') # leap second file
pyswice.unload_c(spiceObject.SPICEDataPath + 'de-403-masses.tpc') # solar system masses
pyswice.unload_c(spiceObject.SPICEDataPath + 'pck00010.tpc') # generic Planetary Constants Kernel
return figureList
if __name__ == "__main__":
run(
True # Show plots
)