International Cometary Explorer

ICE (for International Cometary Explorer) was a second mission of the third ISEE (International Sun-Earth Explorer) spacecraft, ISEE-3. After completion of its primary mission, the spacecraft was sent into solar orbit for flybys of two comets. A complicated route including lunar flybys was used to achieve this using the fuel left over from its primary-mission L1 deployment and stationkeeping. It successfully flew by Comet Giacobini-Zinner in 1985 (the first comet flyby) and Comet Halley in 1986. The spacecraft remains in a solar orbit. The ICE mission was terminated in 1997, but the spacecraft was contacted in 1999, 2008, and 2014, exploring the possibility of using it further, but 2014 attempts to use its propellant failed.

ISEE-3 was launched in 1978 and placed at the Earth-Sun L1 Lagrangian point, the first spacecraft to be deployed at a Lagrangian point. ISEE-3 was an element in a research effort regarding Earth's space weather, including the Sun's influence and was placed so it could monitor the approaching solar wind. Instrumentation was for particle analysis and magnetometery with an X-ray instrument that could also monitor gamma-ray bursts. This primary mission was concluded in 1981. Instruments:

• Solar Wind Plasma Experiment.
• Vector Helium Magnetometer.
• Low Energy Cosmic Ray Experiment.
• Medium Energy Cosmic Ray Experiment.
• High Energy Cosmic Ray Experiment.
• Plasma Wave Instrument.
• Low Energy Proton Experiment, aka Energetic Particle Anisotropy Spectrometer (EPAS).
• Cosmic Ray Electrons and Nuclei.
• X-rays and Electrons Instrument.
• Radio Mapping Experiment.
• Plasma Composition Experiment.
• Heavy Isotope Spectrometer Telescope.
• Ground Based Solar Studies Experiment.