.. _scenarioOrbitManeuver:

scenarioOrbitManeuver
=====================

.. raw:: html

    <iframe width="560" height="315" src="https://www.youtube.com/embed/hkeL50pq0L0" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

Overview
--------

This script sets up a 3-DOF spacecraft which is orbiting Earth.  The purpose
is to illustrate how to start and stop the Xmera simulation to apply
some :math:`\Delta v`'s for simple orbit maneuvers.  Read :ref:`scenarioBasicOrbit`
to learn how to setup an orbit simulation.

The script is found in the folder ``xmera/examples`` and executed by using::

      python3 scenarioOrbitManeuver.py

The simulation layout is shown in the following illustration.  A single simulation process is created
which contains the spacecraft object.  The BSK simulation is run for a fixed period.  After stopping, the
states are changed and the simulation is resumed.

.. image:: /_images/static/test_scenarioOrbitManeuver.svg
   :align: center

When the simulation completes 2 plots are shown for each case.  One plot always shows
the inertial position vector components, while the second plot either shows a plot
of the radius time history (Hohmann maneuver), or the
inclination angle time history plot (Inclination change maneuver).

Illustration of Simulation Results
----------------------------------

The following images illustrate the expected simulation run returns for a range of script configurations.

::

    show_plots = True, maneuverCase = 0

In this case a classical Hohmann transfer is being
simulated to go from LEO to reach and stay at GEO. The math behind such maneuvers can be found
in textbooks such as `Analytical Mechanics of Space Systems <http://arc.aiaa.org/doi/book/10.2514/4.102400>`__.

.. image:: /_images/Scenarios/scenarioOrbitManeuver10.svg
   :align: center

.. image:: /_images/Scenarios/scenarioOrbitManeuver20.svg
   :align: center

::

    show_plots = True, maneuverCase = 1

In this case a classical plane change is being
simulated to go rotate the orbit plane first 8 degrees, then another 4 degrees after
orbiting 90 degrees. The math behind such maneuvers can be found
in textbooks such as `Analytical Mechanics of Space Systems
<http://arc.aiaa.org/doi/book/10.2514/4.102400>`__.

.. image:: /_images/Scenarios/scenarioOrbitManeuver11.svg
   :align: center

.. image:: /_images/Scenarios/scenarioOrbitManeuver21.svg
   :align: center