Physlib.ClassicalMechanics.OrbitalMechanics.VisViva

Given a gravitational system characterized by the gravitational constant $G$ and a central mass $M$, and a configuration with an orbital radius $r$, this function defines the orbital speed $v$ required to maintain a circular orbit, satisfying the relation $v = \sqrt{\frac{GM}{r}}$.

Consider a gravitational system with gravitational constant $G$ and central mass $M$, and an orbiting body at a distance $r$ from the center. If $r > 0$, $G > 0$, and $M > 0$, then the square of the circular orbital speed $v$ satisfies the equation $$v^2 = \frac{GM}{r}$$ where $v$ is the speed required to maintain a circular orbit at radius $r$.