noun. The point at which an orbiting object is farthest away from the center of mass of the body it is orbiting.

noun. The point of a body's elliptical orbit about the system's centre of mass where the distance between the body and the centre of mass is at its maximum.

noun. (astronomy) the point in an orbit farthest from the body being orbited

"Aerobraking would both require an out-of-plane orbit to keep from running the gauntlet of the ring particles for millions of km every orbit and, once the apoapsis was lowered to the distance of the rings, leave the craft moving far slower than the orbital speed of the rings."

periapsis  

celestial point  

aphelion  apogee  apojove  apolune  aposelene