Jet Propulsion Laboratory (U.S.). International Sun-Earth Explorer Team.

Three Explorer-class spacecraft made up the International Sun-Earth Explorer mission, a mother/daughter/ pair (ISEE 1, ISEE 2) and a third craft sent into heliocentric orbit (ISEE 3). The mission was an international cooperative program between NASA and the European Space Agency to study the interaction of the solar wind with the Earth's magnetosphere.

ISEE 1 and 2 were launched together October 22, 1977. Later the heliocentric spacecraft ISEE 3, renamed International Cometary Explorer (ICE), was launched in August 1978. ISEE 1 and 2 followed similar highly elliptic Earth orbits with a small but variable separation between the two to separate spatial from temporal effects in the observations.

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