Submillimeter spectroscopy - water and oxygen: Where are these key species in the interstellar medium?

Water and oxygen are two of the key species necessary for life. Water vapor and molecular oxygen are predicted to be abundant gas phase species in dense regions of the interstellar medium where formation of new stars and planetary systems is taking place. But observations to date have revealed that the abundances of H₂O and O₂ are much lower than expected, and suggest that a surprisingly large amount of atomic oxygen (OI) is present in molecular clouds. Resolving the disagreement between theory and observations will require better spectroscopic observations from new satellite and airborne facilities which fortunately will become available in the next few years. In this talk I briefly review the observations to date, the issues for theoretical models, and suggest what future observations will help resolve this ldquooxygen problemrdquo.