  Determining the distribution and spectral signature of volatile ices and
organics exposed on icy body surfaces can provide crucial clues for deciphering
how the outer solar system formed and evolved. Over the past few decades,
ground- and space-based telescope observations have probed the compositions of
a wide range of icy objects with primordial and processed surfaces, revealing
the presence of numerous volatile ices and organic residues. Although these
telescope observations have advanced our understanding of icy bodies beyond
Saturn, the sensitivity and spatial resolution of collected datasets are
limited by the large heliocentric distances of these far-flung objects.
Furthermore, most observations have focused on the visible (VIS, 0.4 - 0.7
microns) and near-infrared (NIR, 0.7 - 2.5 microns), with fewer observations at
longer NIR wavelengths (2.5 - 5.0 microns) and in the far to near ultraviolet
(UV, 0.1 - 0.4 microns), which represents a critical wavelength region for
investigating modification of ices and organics by UV photolysis and charged
particle radiolysis. Thus, our understanding of icy bodies beyond Saturn is
limited by the capabilities of available facilities, and key questions
regarding their surface compositions remain to be explored. Next generation
space telescopes (NGSTs) with greater sensitivity and angular resolution in the
UV, VIS, and longer NIR are therefore needed to help unveil the surface
compositions of icy bodies residing at the fringes of our solar system.
