.. _scenarioAttitudePointing:

scenarioAttitudePointing
========================

Overview
--------

Demonstrates how to stabilize the attitude tumble without translational motion.
This script sets up a 6-DOF spacecraft, but without specifying any orbital motion.  Thus,
this scenario simulates the spacecraft translating in deep space.  The scenario is a simplified
version of :ref:`scenarioAttitudeFeedback` with the orbital setup removed.

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

    python3 scenarioAttitudePointing.py

As with :ref:`scenarioAttitudeFeedback`, when
the simulation completes 3 plots are shown for the MRP attitude history, the rate
tracking errors, as well as the control torque vector.

The simulation layout is shown in the following illustration.  A single simulation process is created
which contains both the spacecraft simulation modules, as well as the Flight Software (FSW) algorithm
modules.

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

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

::

    show_plots = True, useLargeTumble = False

Here a small initial tumble is simulated.  The
resulting attitude and control torque histories are shown below.  The spacecraft quickly
regains a stable orientation without tumbling past 180 degrees.

.. image:: /_images/Scenarios/scenarioAttitudePointing10.svg
   :align: center

.. image:: /_images/Scenarios/scenarioAttitudePointing20.svg
   :align: center

::

    show_plots = True, useLargeTumble = True

Note that, as expected,
the orientation error tumbles past 180 degrees before stabilizing to zero.  The control
torque effort is also much larger in this case.

.. image:: /_images/Scenarios/scenarioAttitudePointing11.svg
   :align: center

.. image:: /_images/Scenarios/scenarioAttitudePointing21.svg
   :align: center