WATER DETECTION IN AIR STREAM: The Liquid Carryover Detector (LCD) is a passive, un-powered sensor used to detect water droplets present in a flowing stream of air in a microgravity environment. It was designed to characterize the effectiveness of a gas/liquid separator component in NASA’s urine processor. The LCD employs advanced surface treatments and the wicking effect of capillary tubes to arrest water droplets present in the air stream. The capillary tubes then store the liquid where it can be quantified.