THE PROSPECT OF INTERSTELLAR OBJECT EXPLORATIONS FOR SEARCHING LIFE IN COSMOS
Since interstellar objects like 1I/`Oumuamua and 2I/Borisov originate from exoplanetary systems, evenif we do not visit the exoplanetary systems,yby, rendezvous, and sample return missions of interstellarobjects can provide clues to solve the mysteries of cosmic life phenomena such as the origin of exoplanetarysystems, galactic evolution, biosignatures (or even technosignatures), and panspermia. In this paper, wereview space missions for interstellar object exploration in the stage of mission design or concept studysuch as Project Lyra, Bridge, Comet Interceptors, and LightcraftTM. We also review space missions,OSIRIS-REx and NEA Scout, designed for Near Earth Asteroids(NEA) explorations, to investigate thecurrent state of basic technologies that can be extended to explore interstellar objects in a velocity of~ 6AU/year. One of the technologies that needs to be developed for interstellar object exploration is aspacecraft propulsion method such as solar sail, which can catch up with the fast speed of interstellarobjects. If this kind of propulsion becomes practical for space explorations, interstellar object explorationswill mark a new era and serve as a driving force to provide evidences of cosmic life.