# Apsis-Apocenter (minimum speed)

Not Reviewed
Equation / Last modified by KurtHeckman on 2018/05/17 16:11
v_(ap) =
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ID
EmilyB.Apsis-Apocenter (minimum speed)
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6b1a7f36-580e-11e6-9770-bc764e2038f2

The Apsis-Apocenter Minimum Speed calculator computes the minimum speed in an orbit at apogee based on the semi-major axis (a), eccentricity (e), the mass of the primary body (M), and the Universal Gravitational Constant (G).

INSTRUCTION: Choose units and enter the following:

• (M) This is the mass of the primary body.
• (a) This is the semi-major axis of the orbit
• (e) This is the eccentricity of the the orbit

Maximum Orbital Speed(Vap): The calculator returns the velocity in meters per second.  However this can be automatically converted to compatible units via the pull-down menu. The apsides indicate the nearest
and furthest points of an
orbiting body around its host.
(1) farthest - apocenter
(2) nearest - pericenter
(3) focus - primary

#### The Math / Science

The Apsis-Apocenter is an extreme point in an object's orbit. For elliptical orbits about a larger body, there are two apsides. This is commonly known as the apogee. The apocenter is the point furthest away from the object being orbited.

v_(ap) = sqrt ( ((1-e)mu)/((1+e)a) )

where:

## References

Wikipedia (https://en.wikipedia.org/wiki/Apsis)