periapsis

Etymology
.

Noun

 * 1)  The point of a body's (elliptical) orbit in a 2-body gravitational system such that the distance between the two bodies (measured from their respective centres of mass) is at its minimum.
 * 2) * 1983, Richard O. Fimmel, Laurence Colin, Eric Burgess, Pioneer Venus, NASA SP-461, page 109,
 * Figure 5-19. Sun-Venus-Orbiter geometry illustrates how the periapsis moves around the planet during the Venusian sidereal year to sample day and night hemispheres. Because the planet rotates in a retrograde direction, it takes more than one Venusian sidereal year for periapsis to move over all longitudes of the planet (as explained in text).
 * 1) * 2004, R. S. Saunders, et al., Mars Odyssey Mission, C. T. Russell (editor), 2001 Mars Odyssey, Kluwer Academic Publishers, page 34,
 * The main aerobraking phase began once the point of the spacecraft's periapsis had been lowered to within 110 km above the Martian surface.
 * 1) The minimum distance between the two bodies in such a system.
 * 1) The minimum distance between the two bodies in such a system.

Usage notes

 * In the case of some particular celestial bodies, specialized terms are used. See Related terms, below, for examples.

Translations

 * Dutch: perifocus, periapsis
 * Finnish:
 * French: ,
 * Greek:
 * Irish: pearaipsis
 * Portuguese: periapside

Etymology
(see 🇨🇬).

Noun

 * 1)  periapsis