An Etymological Dictionary of Astronomy and Astrophysics
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The Keplerian orbit that a satellite would follow after a specific time t if all forces other than central inverse-square forces ceased to act from time t on. An osculating orbit is tangent to the real, perturbed, orbit and has the same velocity at the point of tangency.

→ osculating; → orbit.

An orbit whose overall shape is like a parabola; it is the limiting case between an elliptical orbit (eccentricity less than 1) and a hyperbolic orbit (eccentricity larger than 1). The speed necessary to form a parabolic orbit is known as the escape velocity.

→ parabolic; → orbit.

A spacecraft orbit that passes over, or close to, the geographic poles of the Earth or some other solar system object.

→ polar; → orbit.

A satellite that revolves around the Earth in an almost north-south orbit, passing close to both poles. The orbits are sun synchronous, allowing the satellite to cross the equator at the same local time each day. These satellites orbit at a height of 830-880 km and take about 100 minutes to complete a turn around the Earth.

→ polar; → orbit; → satellite.

Same as →prograde motion.

→ prograde motion; → orbit.

An orbit which is in → orbital resonance with another orbit.

→ resonance; → orbit.

An orbit with an inclination between 90° and 270° such as those of some comets and small asteroids orbiting the Sun.

→ retrograde; → orbit.

A → European Space Agency (ESA) mission with strong → National Aeronautics and Space Administration (NASA) participation aimed at studying the Sun up close and from high latitudes, launched on 10 February 2020. Solar Orbiter is equipped with 10 instruments and will provide the first images of the Sun's poles. It will make a close approach of the Sun every six months. Its distance from the Sun varies from within the orbit of → Mercury to close to the orbit of Earth. At closest approach, Solar Orbiter will be about approximately 42 million km from the Sun. Solar Orbiter will combine in situ measurements of the → solar wind around the spacecraft with remote sensing, looking at the Sun's features from afar, to connect the two together. The spacecraft has been tested to withstand temperatures up to 500 °C -- enduring thirteen times the amount of solar heating that satellites in Earth's orbit experience. Solar Orbiter will help us understand how our star creates and controls the → heliosphere, i.e. the giant bubble of → plasma that surrounds the whole → Solar System and influences the planets within it.

→ solar; → orbiter.

1) Astro.: A relationship between the orbital period of one body around another and its rotational period on its axis. The relationship results from tidal forces between the two bodies. For example, the rotation period of the Moon equals its revolution period around the Earth.
2) Quantum mechanics: The interaction between a particle's → spin angular momentum and its → orbital angular momentum.

→ spin; → orbit; → coupling.

An orbit in which the satellite revolves about the primary at the angular rate at which the primary rotates on its axis. From the primary, the satellite thus appears to be stationary over a point on the primary.

→ stationary; → orbit.

→ synchronous rotation.

→ synchronous; → orbit.

A shorter → horseshoe orbit confined to the → Lagrangian points L4 or L5.

→ tadpole; → orbit.