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.

The purposes of the missions were to investigate solar-terrestrial relationships at the outermost boundaries of the Earth's magnetosphere and to examine in detail the structure of the solar wind near the Earth and the shock wave that forms the interface between the solar wind and Earth magnetosphere.

ICE's primary scientific objective was to study the interaction between the solar wind and a cometary atmosphere. It flew through the plasma tail of Comet Giacobini-Zinner on September 11, 1985, and was upstream in the solar wind from Comet Halley when several other spacecraft flew close to it. ICE remained in a heliospheric orbit at approximately 1 AU after a total of fifteen propulsive maneuvers, four of which were planned. Five lunar flybys were needed to carry out the transfer from the halo orbit to an escaped trajectory from the earth-moon system. As of May 1995 it operated at a low duty cycle, with some support provided by the Ulysses Project for data analysis.

From the description of International Sun-Earth Explorer Collection, 1978-1982. (Jet Propulsion Laboratory Library and Archives). WorldCat record id: 733100770