森田 泰弘

イプシロンロケットは2013年9月14日に惑星分光観測衛星「ひさき」の打上げに成功し,目標とした軌道投入精度を達成し,新規に開発した誘導制御系の性能を遺憾なく発揮した.イプシロン開発では,惑星探査機「はやぶさ」を投入したM-Vロケットの誘導制御系の性能を継承しつつ新たな技術革新にチャレンジし,M-Vの機能,性能をさらに向上させた誘導制御系を実現した.最終段には信頼性の高い低コストなスラスタを用いた液体推進系の小型ポストブースタ(PBS)を開発し,新たに導入した誘導則とともに軌道投入精度を飛躍的に向上させた.フライトソフトにはM-Vで蓄積した各種シーケンスや姿勢マヌーバ機能をユーティリティ化して搭載し,科学衛星ユーザ等の多様な要望に容易に対応できる機能を実現し運用性を高めた.

The Epsilon rocket, formerly called Advanced Solid Rocket (ASR) launcher, proceeded to the full development phase in August 2010 and its launch site was officially declared to be the Uchinoura Space Center (USC), the home of Japanese solid propellant rocket. The primary purpose of Epsilon is to provide small satellites with a responsive launch that means a low cost, user-friendly and ultimately efficient launch system. The slogan is "Small, Cheap, Fast and Reliable". This outcome is also a result of the excellent endeavors of those who devoted themselves to the next generation solid propellant rocket. However, this is not the final destination. Now that the development was approved, the most important is what the next step should be beyond Epsilon. This paper deals with the significance of the development of Epsilon launch vehicle and how it contributes to the possible evolution of future space transportation systems.