ヤルコフスキー効果
Each of these words was chosen to represent an aspect of this mission. For example, the S, for security means the security of Earth from hazardous NEO. Specifically it refers to better understanding the Yarkovsky effect, that changes the trajectory of the asteroid. Regolith Explorer means that the mission will study the texture, morphology, geochemistry, and spectral properties of the regolith of asteroid Bennu.