This video provides an intuitive understanding of what rotation matrices are and how they are applied to reference frames. It covers the definition of a 3d rotation matrix, euler angles, quaternions, and their uses in spacecraft attitude control. It also covers the difference between active and passive rotations, where an active rotation rotates a physical vector, whereas a passive rotation rotates a reference frame.
Link to videos covering NASA's SPICE software:
• NASA SPICE Files (Ephemeris) | Orbita...
• Solar System Orbits with SPICE Files ...
Link to video introducing Earth groundtracks:
• Groundtracks Introduction | Orbital M...