scenarioAttitudeGG
Overview
Illustrates how to add a Module: GravityGradientEffector to a 6U cube-sat spacecraft while a Hill-frame pointing control solution is active. This script expands on scenarioAttitudeGuidance sets up a 6-DOF spacecraft which is orbiting the Earth. More illustrations on using the gravity gradient torque effector can be found in the modules _UnitTest folder.
The script is found in the folder basilisk/examples and executed by using:
python3 scenarioAttitudeGG.py
The simulation layout is shown in the following illustration. The Module: GravityGradientEffector is added to the spacecraft to create a position depended external torque. This
Illustration of Simulation Results
In this simulation the reference frame is not aligned with the Hill frame, but rather it has a fixed angular offset along the 2nd body axis. As the Body frame inertia tensor is diagonal, this reference orientation represents a non-equilibrium gravity gradient torque orientation. Thie simulation results are shown in the following figures:
Where in scenarioAttitudeGuidance the attitude error asymptotically converged to zero, with the gravity gradient torque the closed loop dynamics is now only Lagrange stable or bounded.