What is apogee?
Also called: highest point of an orbit
Apogee is the point in an orbit where a spacecraft is furthest from Earth. Orbits are usually ovals rather than circles, so there is a far point and a near point.
A satellite in an oval orbit is not travelling at a steady speed. It slows as it climbs towards apogee and speeds up as it falls back towards the near point — for the same reason a ball thrown upwards is slowest at the top.
That makes apogee a useful place to fire an engine. A small push there changes the far side of the orbit efficiently, which is how spacecraft raise themselves into the orbit they actually want.
The word only applies to orbits around Earth. Around the Sun it is aphelion; around the Moon, apolune.
See it happen
Space & OrbitsFalling foreverSource: International Space Station