Hayabusa2 ground operation systems for asteroid proximity operation

Abstract

Hayabusa2 is a sample return mission to the C-type asteroid 162173 Ryugu. Hayabusa2 was launched by the Japan Aerospace Exploration Agency in December 2014 and will arrive at the asteroid vicinity in the summer of 2018. Hayabusa2 will explore Ryugu for 1.5 years and return to the Earth in winter 2020. The entire flight period of Hayabusa2 is divided into 4 phases; (i)EDVEGA (launch to Earth gravity assist), (ii) Transfer (Earth gravity assist to asteroid arrival), (iii) Asteroid Proximity, (iv) Return (asteroid to Earth reentry). Different operations are required in each phase. Especially in the asteroid proximity phase, there are many critical events such as low-altitude observation, touching down, rover deployment and crater forming. There are some difficult characteristics in performing these critical operations from ground; navigation and guidance in the submeter accuracy against the microgravity environment of Ryugu, 40 minutes round-trip light time due to the 3.6 billion kilometers distance between Hayabusa2 and the Earth. We have developed a ground operation system to clear the characteristics. This paper presents the ground operation systems overview for Asteroid Proximity Operation to realize high quality operation for mission success.