This discretionary time proposal results from our previous projects
ABAUDRY.PROP_OD1 and ABAUDRY.CORE_OD2.  We request 'exceptional' observing
time on the ISO-LWS spectrometer in the direction of Orion-KL. In this
source we wish to detect the same three IR lines of OD as in
ABAUDRY.PROP_OD1 and ABAUDRY.CORE_OD2 .  The OD radical, although predicted
to be abundant by various chemical scenarios, has never been observed in
space but will give important clues to D fractionation.  The selected OD
lines correspond to energy levels comparable to or lower than those
involved in detected HDO and OH lines.  From this, and because of the
relatively high temperatures of the hot cores we infer that OD will be
excited and will allow us to estimate its abundance relative to OH.