Although this satellite is located deep in Jupiter's gravitation well, there
are less than 20 surface features that could be impact craters. This fact,
combined with a
strong infrared spectral signature indicating the surface is covered with a
fractured glacier field, has raised the expectation that signatures due to
ongoing resurfacing processes can be detected. Spatially resolved ultraviolet
observations should provide additional constraints for a model of these
processes. FOS spectra of the trailing hemisphere of Europa were obtained on
July 17, 1993. These data spanned 222-329 nm with 0.209 nm resolution and a
signal-to-noise ratio ranging from 3.4 to 37 (far surpassing IUE observations).
The albedo showed a marked discontinuity near 280 nm. Noll et al. (1994)
question that this feature is due to sulfur-ion-irradiated ice and suggest it
is absorption of solid SO
on water ice. Based on the lack of detection of
the OH A-X (0,0) band at 3090 
, they set an upper limit on the column
abundance of OH at 2
10
cm
. This rate will constrain
escape rates of H
O and OH molecules that could be produced in Europa's
resurfacing processes.