Development Results of Loop Heat Pipe for Flexibility and Heat Transport in the DESTINY+

The Deep Space Exploration Technology Demonstrator (DESTINY+) mission will conduct a flyby observation of the asteroid Phaethon, utilizing ion engine propulsion. On this route, DESTINY+ needs to operate even when its ion thrusters are exposed to direct sunlight. To maintain the ion thruster temperature within the allowable temperature, a loop heat pipe (LHP) is employed to transport heat from the ion thruster to the dedicated radiator for dissipation. As the ion thruster pivots to control thrust direction, the LHP must accommodate the resulting displacement in the heat transport lines. For this purpose, DESTINY+ LHP incorporates a flexible structure designed to repeatedly absorb significant displacements of approximately ±21 mm along the orbit for over 24,000 cycles in the section connecting the vapor and liquid lines. This paper details the specifications and development outcomes of an LHP engineered to meet these requirements.