The International Sun-Earth Explorer, or ISEE, program was an international cooperative program between NASA and ESA designed to study the interaction of the solar wind with Earth’s magnetic system, the magnetosphere. The three ISEE spacecraft measured energetic particles, electric and magnetic fields, and plasma parameters.
ISEE 3 orbited the L1 Lagrange point, a stable gravitational point between the sun and Earth, about a million miles away from Earth. There, ISEE 3 continuously monitored the changing space environment, shedding light on how energy is transferred between the solar wind and Earth’s magnetosphere. In 1982, ISEE 3 began a new mission as the International Cometary Explorer, or ICE. ICE made direct measurements of interaction between the solar wind and the ionized tail of Comet Giacobini-Zinner. ICE also coordinated observations with the Ulysses mission to study coronal mass ejections and cosmic rays.