periapsis

Definitions

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. The minimum distance between the two bodies in such a system.

Equivalents

Examples

“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).”

“We don't always want⟳ to burn near periapsis. Suppose⟳ we want⟳ to change⟳ the height at periapsis. The most efficient place⟳ to change⟳ the radius of periapsis is at apoapsis. Consider⟳ applying #92;Deltav at some other point⟳ in the orbit. In this case both periapsis and apoapsis will change⟳. If we apply⟳ the #92;Deltav tangentially at apoapsis, all of the #92;Deltav will go into changing periapsis, and vice versa.”

“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.”

CEFR level