The Tsiolkovsky Rocket Equation, foundational to astronautics, mathematically describes the motion of vehicles that follow the basic principle of a rocket: a device that can apply acceleration to itself by expelling part of its mass with high speed, thereby moving due to the conservation of momentum. It highlights the relationship between the velocity of the rocket, the effective exhaust velocity of the expelled mass, and the mass ratio of the rocket before and after the expulsion of mass.