  We present 0.8 to 2.4 micron spectral observations of uranian satellites,
obtained at IRTF/SpeX on 17 nights during 2001-2005. The spectra reveal for the
first time the presence of CO2 ice on the surfaces of Umbriel and Titania, by
means of 3 narrow absorption bands near 2 microns. Several additional, weaker
CO2 ice absorptions have also been detected. No CO2 absorption is seen in
Oberon spectra, and the strengths of the CO2 ice bands decline with
planetocentric distance from Ariel through Titania. We use the CO2 absorptions
to map the longitudinal distribution of CO2 ice on Ariel, Umbriel, and Titania,
showing that it is most abundant on their trailing hemispheres. We also examine
H2O ice absorptions in the spectra, finding deeper H2O bands on the leading
hemispheres of Ariel, Umbriel, and Titania, but the opposite pattern on Oberon.
Potential mechanisms to produce the observed longitudinal and planetocentric
distributions of the two ices are considered.
