Suisei
Suisei (PLANET-A)
Mission Descriptions
"Suisei" was launched in 1985 to observe Halley's Comet, which had returned to Earth after a 76-year absence. It conducted large-scale international cooperative observations with Japan's "Sakigake" and "Suisei", ESA's "Giotto", two Soviet "Vega" spacecraft, and the U.S. "ICE". In March 1986, they approached Halley's comet and obtained many results, including the rotation period of Halley's comet by ultraviolet imaging, measurement of changes in the water ejection rate, and how ions originating from Halley's comet were captured by the solar wind. These six Halley's comet explorers were called the "Halley Armada".