A joint NASA–ESA series of probes to study the Earth's magnetosphere and the Sun's effect on it. The ISEE-1 and ISEE-2 spacecraft were both launched in 1977 October into orbits that carried them together into the magnetosphere. The instruments on board included magnetometers and particle detectors. ISEE-3 was launched in 1978 August into an orbit completely outside the magnetosphere to measure the solar wind flow independent of any influence from the Earth. ISEE-3 was later sent to intercept Comet Giacobini–Zinner, and was renamed the International Cometary Explorer (ICE).
Subjects: Astronomy and Astrophysics — Earth Sciences and Geography.