Planetary: Multiple, unique studies of distant KBO populations not yet well   studied by New Horizons; unique, high-phase studies of several Kuiper belt    dwarf planets; large-phase angle studies of the ice giants Uranus and Neptune with direct application to exo-ice giants as well as themselves; and otherwiseunobtainable measurements of in situ Kuiper belt dust density as a function ofheliocentric distance.                                                                                                                                      Heliophysics: New outer heliosphere measurements not performed by Voyager     or Pioneer of particle populations and processes that ultimately shape the    various heliospheric boundaries; observations of dust and hydrogen gas in     the outer solar system; and important collaborative synergies with other      heliophysics missions ranging from the inner solar system to the ISM in       the most widely spaced Heliophysics System Observatory to date.                                                                                             Astrophysics: Potentially paradigm-shifting astrophysical studies of the      cosmic optical and ultraviolet backgrounds with unprecedented sensitivity     owing to New Horizon's position beyond the zodiacal light; and unique UV      observations of the local interstellar medium.