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  2. Earth-centered inertial - Wikipedia

    en.wikipedia.org/wiki/Earth-centered_inertial

    Earth-centered inertial (ECI) coordinate frames have their origins at the center of mass of Earth and are fixed with respect to the stars. [1] " I" in "ECI" stands for inertial (i.e. "not accelerating "), in contrast to the "Earth-centered – Earth-fixed" ( ECEF ) frames, which remains fixed with respect to Earth's surface in its rotation ...

  3. Longitude of the ascending node - Wikipedia

    en.wikipedia.org/wiki/Longitude_of_the_ascending...

    The longitude of the ascending node (bright green) as a part of a diagram of orbital parameters.. The longitude of the ascending node, also known as the right ascension of the ascending node, is one of the orbital elements used to specify the orbit of an object in space.

  4. Orbital elements - Wikipedia

    en.wikipedia.org/wiki/Orbital_elements

    Keplerian elements can be obtained from orbital state vectors (a three-dimensional vector for the position and another for the velocity) by manual transformations or with computer software. [1] Other orbital parameters can be computed from the Keplerian elements such as the period, apoapsis, and periapsis. (When orbiting the Earth, the last two ...

  5. Orbital state vectors - Wikipedia

    en.wikipedia.org/wiki/Orbital_state_vectors

    Orbital position vector, orbital velocity vector, other orbital elements. In astrodynamics and celestial dynamics, the orbital state vectors (sometimes state vectors) of an orbit are Cartesian vectors of position and velocity that together with their time () uniquely determine the trajectory of the orbiting body in space.

  6. Earth-centered, Earth-fixed coordinate system - Wikipedia

    en.wikipedia.org/wiki/Earth-centered,_Earth...

    The Earth-centered, Earth-fixed coordinate system (acronym ECEF), also known as the geocentric coordinate system, is a cartesian spatial reference system that represents locations in the vicinity of the Earth (including its surface, interior, atmosphere, and surrounding outer space) as X, Y, and Z measurements from its center of mass.

  7. Kepler orbit - Wikipedia

    en.wikipedia.org/wiki/Kepler_orbit

    The following image illustrates a circle (grey), an ellipse (red), a parabola (green) and a hyperbola (blue) A diagram of the various forms of the Kepler Orbit and their eccentricities. Blue is a hyperbolic trajectory (e > 1). Green is a parabolic trajectory (e = 1). Red is an elliptical orbit (0 < e < 1). Grey is a circular orbit (e = 0).

  8. Ephemeris - Wikipedia

    en.wikipedia.org/wiki/Ephemeris

    In astronomy and celestial navigation, an ephemeris (/ ɪ ˈ f ɛ m ər ɪ s /; pl. ephemerides / ˌ ɛ f ə ˈ m ɛr ɪ ˌ d iː z /; from Latin ephemeris 'diary', from Ancient Greek ἐφημερίς (ephēmerís) 'diary, journal') [1] [2] [3] is a book with tables that gives the trajectory of naturally occurring astronomical objects and artificial satellites in the sky, i.e., the position ...

  9. Kepler's laws of planetary motion - Wikipedia

    en.wikipedia.org/wiki/Kepler's_laws_of_planetary...

    A diameter would cut the orbit into equal parts, but the plane through the Sun parallel to the equator of the Earth cuts the orbit into two parts with areas in a 186 to 179 ratio, so the eccentricity of the orbit of the Earth is approximately