An Opportunity for Astrophysics from the Outer Solar System

The outer solar system is a unique, quiet vantage point from which to observe the universe around us. Astrophysical measurements from beyond 5 AU can enable several niche astrophysical science cases that are too difficult to perform from platforms near Earth, including building a detailed understanding of the cosmic extragalactic background throughout the electromagnetic spectrum, measurements of the properties of dust and ice in the outer solar system, searches for moons and other small, faint structures around exoplanets, determinations of the mass of planets far from their parent stars using gravitational microlensing, rapid follow-up of gravitational wave transient events, and fundamental physics. A future mission to the ISM offers a unique opportunity to impact all of these science cases in a profound way not available from platforms closer to Earth. Further, performing astrophysical measurements during a cruise phase of such a mission offers an opportunity to provide both high-impact science during the long quiescent periods en route to the ISM, as well as to maintain technical expertise over generations of scientists and engineers. In this talk, I will outline some of the science impacts such a mission could have, and discuss some options for realizing instruments and measurements that would be of interest in the next decade and beyond.