# orbital velocity

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## orbital velocity

The velocity of a satellite or other orbiting body at any given point in its orbit. It is also the velocity required by a satellite to enter an orbit around a body. The orbital velocity, v, is given by the expression
v = √[gR 2(2/r – 1/a )]
where R is the radius of the orbited body, r is the distance from the center of mass of the system (i.e. from the approximate center of the primary), a is the semimajor axis of the orbit, and g is the standard acceleration of gravity. For a circular orbit, r = a and the circular velocity is given by
v = √(gR 2/r )

To escape from an orbit a must tend to infinity and the escape velocity is then given by

v e = √(2gR 2/r )

The orbital period for an elliptical orbit is given by

P = 2πa 3/2/√gR 2

## orbital velocity

[′ȯr·bəd·əl və′läs·əd·ē]
(astronomy)
The instantaneous velocity at which an earth satellite or other orbiting body travels around the origin of its central force field.
References in periodicals archive ?
Also, since F9 aims to get to orbital velocity, its velocity at approximately 9000 kmph is thrice as high during separation as the SN's 3000 kmph.
numerically evaluated the orbital velocity, particularly its horizontal components, including the effect of nonlinearity and current;
If the effects of the HM and the horizontal component of orbital velocity are both ignored, (18) and (19) are further simplified as
It is not sufficiently powerful to reach orbital velocity on its own so has to be launched by a rocket.
Orbital velocity keeps space objects from being pulled in by gravity from a larger body such as the Sun.
Highlights include file footage of Sergei Korolev, designer of the R-7 rocket that launched Sputnik, and a lucid illustration of Isaac Newton's concept of orbital velocity.
The second and third stages separated successfully and the missile reached orbital velocity, but the attempt failed because the third-stage booster malfunctioned.
Post-flight review of telemetry has verified that the Falcon 1 began to spin during the second stage, that being the only obstacle preventing it from reaching full orbital velocity.
The cargo is transferred from one orbit to the other using the orbital velocity of the system.
It doesn't actually go into orbit and it can't put anything else into orbit, because it can't achieve orbital velocity.
When the bottom orbital velocity is less than the magnitude of the steady current then the flow direction does not reverse and the mean current profile is advected back and forth.
To get from a standing start to orbit, the NASP will need at least three different engine systems, including turbojets to allow the plane to fly at low speeds; an as-yet-theoretical ramjet/scramjet combination, which will take the plane from supersonic to hypersonic speeds; and rockets to accelerate the plane to and from orbital velocity.

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