# circular velocity

Circular velocity is the horizontal velocity of an object required
to keep it in a circular orbit at a given
altitude about a planet or other gravitating mass.
It is given by √[*G*(*M* + *m*)/*R*], where *G* is the gravitational constant, *M* is the mass of the central body, *m* is the mass of the orbiting
body (which can be ignored, for example, in the case of an orbiting spacecraft),
and *R* is the distance separating the orbiter from the center of the
gravitating body.