Orbiter
An orbiter is a spacecraft that goes into orbit around a planet, moon or asteroid to study it for a long time.
An orbiter is a spacecraft that slows down on arrival and settles into orbit around its target, allowing long, detailed study. It can map the whole surface, measure gravity and watch changes over time.
Orbiting a small asteroid is tricky because its gravity is so weak. NASA's NEAR Shoemaker became the first spacecraft to orbit an asteroid when it reached Eros in February 2000. Dawn later orbited both Vesta, from 2011 to 2012, and the dwarf planet Ceres, from 2015 to 2018. OSIRIS-REx orbited Bennu at a distance of only about a kilometre, one of the closest orbits ever achieved around a planetary body.
Orbiters provide the context that samples and meteorites cannot. Their maps of minerals, craters and gravity show where a meteorite might have come from on its parent body, and how the body's surface and interior are built.
Related terms
Level: Explorer Ages 10 and up