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In gravitationally bound systems, the orbital speed of an astronomical body or object (e.g. planet, moon, artificial satellite, spacecraft, or star) is the speed at which it orbits around either the barycenter (the combined center of mass) or, if one body is much more massive than the other bodies of the system combined, its speed relative to the center of mass of the most massive body.
is the orbital velocity of the orbiting body, is radius of the circle is angular speed, measured in radians per unit time. The formula is dimensionless, describing a ratio true for all units of measure applied uniformly across the formula.
A wide variety of sources [5] [6] [7] define LEO in terms of altitude.The altitude of an object in an elliptic orbit can vary significantly along the orbit. Even for circular orbits, the altitude above ground can vary by as much as 30 km (19 mi) (especially for polar orbits) due to the oblateness of Earth's spheroid figure and local topography.
Geosynchronous (and geostationary) orbits have a semi-major axis of 42,164 km (26,199 mi). [10] This works out to an altitude of 35,786 km (22,236 mi). Both complete one full orbit of Earth per sidereal day (relative to the stars, not the Sun). High Earth orbit: geocentric orbits above the altitude of geosynchronous orbit (35,786 km or 22,236 mi).
Geocentric orbit with apogee above 35,786 km and low perigee (about 1,000 km) that result in long dwell times near apogee. Molniya orbit A highly elliptical orbit with inclination of 63.4° and orbital period of ½ of a sidereal day (roughly 12 hours). Such a satellite spends most of its time over a designated area of the Earth. Tundra orbit
Using the local velocity and radius given in the last example, one finds = km s −1 kpc −1 and = km s −1 kpc −1. This is close to the actual measured Oort constants and tells us that the constant-speed model is the closest of these three to reality in the solar neighborhood.
Its orbital characteristics are ... is a 1,000 km-wide basin of frozen ... This gives Pluto an escape velocity of 4,363.2 km per hour / 2,711.167 miles per hour (as ...
Radial parabolic trajectory, a non-periodic orbit where the relative speed of the two objects is always equal to the escape velocity. There are two cases: the bodies move away from each other or towards each other. Radial hyperbolic trajectory: a non-periodic orbit where the relative speed of the two objects always exceeds the escape velocity ...