Not Even Halfway There: New Horizons' Future Exploration of the Heliosphere, the Outer Solar System, and Beyond

This article gives an overview of New Horizons' past, present, and future exploration of the heliosphere, including descriptions of the planned future investigations by the plasma and particle instruments Solar Wind Around Pluto (SWAP) and Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI). These investigations include the evolution of the solar wind, pickup ions, energetic particles, and galactic cosmic rays in the outer heliosphere, as well as the propagation of the solar disturbances throughout the heliosphere. The article also presents the observation plans for the ultraviolet spectrograph Alice, which consist of all-sky imaging in search for signatures of the hydrogen wall and interstellar clouds beyond the heliopause and also measurements of the hydrogen column density between New Horizons and other spacecraft in the inner solar system. In addition, it discusses the past measurements of circumsolar dust by the Venetia Burney Student Dust Counter (VBSDC) and the search for interstellar dust grains. Lastly, it presents an overview of the planned observations by the Long Range Reconnaissance Imager (LORRI), including of distant Kuiper Belt objects and the cosmic optical background.