Elliptic Orbit - Velocity

Velocity

Under standard assumptions the orbital speed of a body traveling along elliptic orbit can be computed from the Vis-viva equation as:

where:

• is the standard gravitational parameter,
• is the distance between the orbiting bodies.
• is the length of the semi-major axis.

The velocity equation for a hyperbolic trajectory has either +, or it is the same with the convention that in that case a is negative.