SAWAI SHUJIRO

In this chapter, the development procedure and the operation of Hayabusa2 bipropellant chemical propulsion system are described in detail. Lessons learned from the original Hayabusa (sample return mission from the asteroid Itokawa) and Akatsuki (Venus climate orbiter mission) are described, and the countermeasures incorporated into the design of Hayabusa2 chemical propulsion system are detailed. On-orbit data is used to assess the impulse provided by each thruster. In particular, the cause of thrust variability under pulsed operation is investigated, and approaches to ensure stable and reliable thruster operation are proposed. Furthermore, the relation between thrust duration and generated impulse is modeled to enable reliable reproduction of the required ΔV.