.. _scenarioHaloOrbit:

scenarioHaloOrbit
=================

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 ``xmera/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