Goals: International Sun-Earth Explorer-3 (ISEE-3) was to
investigate the solar wind and its interaction with Earth's
magnetic field, among other phenomena in interplanetary space.
It was later renamed International Cometary Explorer (ICE) and
used to study two comets during an extended mission.
Accomplishments: ISEE-3 conducted the first deep survey of
Earth's magnetic tail. Then, after a series of complex flybys of
the Moon, the spacecraft was renamed the International Cometary
Explorer (ICE) and became the first spacecraft to fly past a
comet (Giacobini-Zinner). Its observations supported the theory
that comets are "dirty snowballs." The following year, it joined
international exploration of Comet Halley by providing data on
the solar wind approaching the comet.