The Explorer-class heliocentric spacecraft, International Sun-Earth Explorer 3, was part of the mother/daughter/heliocentric mission (ISEE 1, 2, and 3). The purposes of the mission were: (1) to investigate solar-terrestrial relationships at the outermost boundaries of the Earth's magnetosphere; (2) 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's magnetosphere; (3) to investigate motions of and mechanisms operating in the plasma sheets; and, (4) to continue the investigation of cosmic rays and solar flare emissions in the interplanetary region near 1 AU. The three spacecraft carried a number of complementary instruments for making measurements of plasmas, energetic particles, waves, and fields. The mission thus extended the investigations of previous IMP spacecraft. The launch of three coordinated spacecraft in this mission permitted the separation of spatial and temporal effects.
Termination of operations of ICE/ISEE3 was authorized May 5, 1997.