Trojan Lander Experiments In The Solar Powered Sail Mission

Abstract

A landing experiment on a Jupiter Trojan asteroid is under study in the Solar Powered Sail (SPS) mission. The SPS is based on the advanced hybrid propulsion system using the large area thin film solar array as the space yacht (inherited from IKAROS mission) and the ion engine (inherited from Hayabusa and Hayabusa2 missions), enabling the spacecraft to visit outer solar system without using a radioactive thermoelectric generator (RTG). After more than 10 years cruise to a Trojan asteroid, the spacecraft will observe the asteroid globally from the home position to characterize it. Then a 100 kg class lander will be deployed to land on the surface. The lander has about 20 kg mission instruments. When it is landed, it looks around the surroundings with panoramic imagers to characterize the geologic context and under the body with a monitor camera whether it is properly landed and ready for sampling the surface materials. If not, the lander will relocate by hopping. The surface and subsurface materials are sampled and investigated with visible and infrared microscopes to characterize the physical properties and mineral composition of them. Part of those samples are heated so that volatiles are evaporated to conduct high resolution mass spectroscopy. Isotopic ratios of nitrogen, hydrogen, and oxygen are key information to solve the origin and evolution of the asteroid, and also the solar system, because it is essential question whether the Jupiter Trojans originated around the outer asteroid belt, or from the outer solar system region. We will present the current design of surface landing experiments and the strawman payloads.