Orbital velocity simply means the gravitationally bound system of the orbital velocity or speed of the bodies or objects like the moon, planets, artificial satellites and spacecraft or star at which the speed of its orbit around the barycenter or when the object is much less massive than the largest body in the system. Two things depend on the speed in this latter case which is may be relative to the surface of that larger body or relative to its center of mass. This particular term can be used to refer to either the mean orbital speed that is the average speed over the entire orbit or to it’s instantaneous the peed at a particular point on its orbit. When a system approximates a two-body system only that time orbital speed at a given point at the orbit can be computed from its distance e to the central body and the objects specific orbital energy which is also known as total energy.

## What are the radial trajectories?

This is assumed that the system is a two-body system and the objects which are also known as orbiting objects that have negligible mass as compared to the larger or center objects. Specific orbital energy or total energy equal to kinetic energy minus potential energy and the sign of the results may be as zero, positive or negative and these signs tell more about the type of orbits such as if the total energy is positive the orbit is unbound or open and also follows hyperbola with larger bodies. Of the total energy is zero that the orbit is a parabola with focus at other body and lastly if the total energy is negative then the orbit is bound or closed and the motion will be eclipsed with focus at the other body.

## Why transverse orbital speed and mean orbital speed?

Because of the law of conversion the angular momentum the transverse orbital speed is inversely proportional to the distance to the center body. It mentions if the body moves around its orbit during a fixed amount of time the line from the barycenter to the body sweeps a constant area of the orbital plane because of which parts of its orbit the body traces during that particular period of time. Whereas mean orbital speed can be concluded from orbits with small eccentricity in which the length of the orbit is close to that of a circular one. The gravitational two-body problem happens when one of the body is not of the considerably less mass.