Science Fair Project Encyclopedia
Specific relative angular momentum
In astrodynamics specific relative angular momentum (
) of orbiting body (
) relative to central body (
) is the relative angular momentum of per unit mass. Specific relative angular momentum plays a pivotal role in definition of orbit equations.
Specific relative angular momentum ()is defined as cross product of position vector and velocity vector of :
where:
is orbital position vector of orbiting body relative to central body,
is orbital velocity vector of orbiting body relative to central body.
Under standard assumptions for a orbiting body in a trajectory around central body at any given time the vector is perpendicular to the osculating orbital plane defined by orbital position and velocity vectors.
The magnitude of is denoted as 
:
For an elliptical orbit, it is twice the area per unit time swept out, hence twice the area of the ellipse divided by the orbital period, hence 
, which is 
.
The units of are km2s-1.
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details