Halley's Comet Exploration in Japan : Japan's First Interplanetary Flight

摘要

Since the first Japanese successful satellite "OHSUMI" launched in 1970, Japan's science made efforts in sending scientific satellites to orbit around earth almost every year. Launch vehicles for the satellites were Mu-series which evolved step by step in response to the demand of space science of the days. When Halley's comet was found to come back toward the sun after 76 years in 1985-86, ISAS (Institute of Space and Astronautical Science) began to prepare Japan's first interplanetary spacecraft to observe the Comet taking the opportunity. Japan had to solve four problems to achieve the task: a new launch vehicle, new type spacecraft, a big antenna, and new software for interplanetary flight. The problems were overcome at last, and two Halley's comet explorers, SAKIGAKE and SUISEI, were launched from Uchinoura launch site using M-3SII rocket newly developed, and the tracking operation was successfully done with 64 meter antenna newly constructed at Usuda. These two Halley's comet missions marked the epoch in pushing Japan's space science onto international stage, and, at the same time, initialized Japan's solar system exploration. This paper reviews the process from the proposal to the end of missions when four space agencies gathered at Vatican Palace to make reports to the Pope in 1986.