Earth & SkyGreek → English
Apoapsis
/ˌæpoʊˈæpsɪs/noun
The point in an orbit farthest from the body being orbited.
The Greek roots
ἀπό
apó
away from
ἁψίς
hapsís
arch, orbital turning point
Literally: “away from the arch-point”
The story of the word
Astronomers usually name the central body instead, so it is apogee round the earth, aphelion round the sun and apastron round another star. Apoapsis is the general term you need when the thing at the centre is Mars, or a comet nucleus, or unnamed. Orbital mechanics then hands you a rule that reads like a paradox: to raise your apoapsis on the far side, burn at the near side.
- How it travelled
- Ancient Greek → scientific coinage → English
- First recorded
- 20th century
Same family
apogeeaphelionperiapsisapsisapostle
In a sentence
The probe reaches apoapsis eight days after the burn and barely moves for a while.