  From orbit, the visibility of Titan's surface is limited to a handful of
narrow spectral windows in the near-infrared (near-IR), primarily from the
absorption of methane gas. This has limited the ability to identify specific
compounds on the surface -- to date Titan's bulk surface composition remains
unknown. Further, understanding of the surface composition would provide
insight into geologic processes, photochemical production and evolution, and
the biological potential of Titan's surface. One approach to obtain wider
spectral coverage with which to study Titan's surface is by decreasing the
integrated column of absorbers (primarily methane) and scatterers between the
observer and the surface. This is only possible if future missions operate at
lower altitudes in Titan's atmosphere. Herein, we use a radiative transfer
model to measure in detail the absorption through Titan's atmosphere from
different mission altitudes, and consider the impacts this would have for
interpreting reflectance measurements of Titan's surface. Over our modeled
spectral range of 0.4 - 10 micron, we find that increases in the width of the
transmission windows as large as 317% can be obtained for missions performing
remote observations at the surface. However, any appreciable widening of the
windows requires onboard illumination. Further, we make note of possible
surface compounds that are not currently observable from orbit, but could be
identified using the wider windows at low altitudes. These range from simple
nitriles such as cyanoacetylene, to building blocks of amino acids such as
urea. Finally, we discuss the implications that the identifications of these
compounds would have for Titan science.
