madâr-e Kepleri (#)
Fr.: orbit keplérienne
The orbit of a spherical object of a finite mass around another spherical object, also of finite mass, governed by their mutual → gravitational forces only.
Fr.: orbite de Lissajous
A quasi-periodic path resembling a → Lissajous figure around the L1 or L2 → Lagrangian points of a two-body system. Lissajous orbits, resulting from a combination of planar and vertical components, are used by certain space telescopes (such as → WMAP, → Planck Satellite, and → Herschel Satellite) that are required to be in a stable position relative to the Earth and Sun while making long-term observations.
lunar orbit node
gereh-e madâri-ye mâh
Fr.: nœud de l'orbite lunaire
Same as → lunar node.
lunar sidereal orbital period
dowre-ye madâri-ye axtari-ye mâng
Fr.: période orbitale sidérale de la Lune
Same as → sidereal month.
minimum orbit intersection distance (MOID)
durâ-ye kamine-ye andarsekanj-e madâr
Fr.: distance minimale d'intersection d'une orbite
The minimum distance between the paths of two orbiting objects around a → primary. Such distance between an object and Earth is called Earth MOID.
The path followed by a body moving in a gravitational field. For bodies moving under the influence of a centrally directed force, without significant perturbation, the shape of the orbit must be one of the conic section family of curves (circle, ellipse, parabola, or hyperbola).
L. orbita "wheel track, course, circuit."
Madâr, from Ar.
Fr.: déclin d'orbite
A gradual change in the orbit of a spacecraft caused by aerodynamic drag of a planet's outer atmosphere and other forces.
1) madâri; 2) madârâl
Fr.: 1) orbital; 2) orbitale
1) Of or relating to an orbit.
orbital angular momentum
jonbâk-e zâviyeyi-ye madâri
Fr.: moment cinétique orbital, ~ angulaire ~
1) Mechanics: The → angular momentum
associated with the motion of a particle about an origin, equal to the cross product
of the position vector (r) with the linear momentum (p = mv):
L = r x p. Although r and p are constantly changing
direction, L is a constant in the absence of any external force on the system.
Also known as orbital momentum.
Fr.: axe orbital
Fr.: débris spatial
Objects in orbit around Earth created by humans, that no longer serve any useful purpose. They consist of everything from entire spent rocket stages and defunct satellites to explosion fragments, paint flakes, dust, and slag from solid rocket motors, and other small particles. Also called space junk and space waste.
elektron-e madâri (#)
Fr.: électron orbital
An electron contained within an atom which may be thought of as orbiting around the nucleus, in a manner analogous to the orbit of a planet around the Sun.
Fr.: élément orbital
Any of the six parameters needed to specify the → orbit of an object around a → primary body (such as a planet around the Sun or a satellite around the Earth) and give its position at any instant. Two of them define the size and the form of the orbit: → semi-major axis (a) and → eccentricity (e). Three angular values determine the orbit position in space: the → inclination (i) of the object's → orbital plane to the reference plane (such as the → ecliptic), the → longitude of ascending node (Ω), and the → argument of periapsis (ω). And finally the sixth element is the → time of periapsis passage which allows calculating the body's position along the orbit at any instant.
Fr.: énergie orbitale
Fr.: inclinaison orbitale
An → orbital element that defines the angle between the orbital plane of a solar system body (planet, comet, asteroid) and the plane of the ecliptic. The orbital inclination of the Earth's orbit is 0°; those of Mercury, Venus, and Mars are 7.01°, 3.39°, and 1.85° respectively.
Fr.: mainoeuvre orbitale
The moving of a spacecraft between two different orbits resulting from a change in its velocity (acceleration). Generally, manoeuvres are caused by → thrust from the spacecraft's motors.
Fr.: mainoeuvre orbitale
Fr.: migration orbitale
Theoretical prediction according to which a → giant planet, formed in the outer regions of a → protoplanetary disk, could migrate inward by losing → energy and → angular momentum as the result of → gravitational interactions with the remnants of the disk. This orbital migration could explain the presence of giant gaseous Jupiter-like planets (→ hot Jupiters) very close to their host stars.
Fr.: nœud orbital
One of the two points of intersection of the orbit of a secondary body with the plane of reference through the primary.
Fr.: paramètre orbital