OPENS-0: an outer planet exploration mission providing opportunities for multi-site observations of diffuse background light

We are planning a new concept OPENS (Outer Planet Exploration by Novel Small Spacecraft) program that will explore the outer planet region with a series of small spacecraft in a shorter development time and at a lower cost than legacy spacecraft. OPENS-0, which was selected as a JAXA Eco & Fast Class candidate, is a technology demonstration mission to Saturn. During its cruise phase, OPENS-0 will provide astronomical science opportunities, including observations of the ZL, EBL, and other diffuse background light, using onboard multipurpose cameras. This paper presents an overview of the OPENS-0's instruments and scientific objectives, as well as an introduction to the OPENS program.