Skylab Waste Management System Urine Separator, measuring 14˝ x 11˝ x 4˝, with a Hamilton Standard label on the side: "Urine Separator Assembly, MDAC Spec. 1B87234H, Stock No. 3810-0050, Serial No. 00316, Part No. SV722959-19, Cont No. NAS9-6555." The opposite side has tubes marked "Urine Inlet," "Gas Outlet," and "Urine Outlet," and protective covers over the brackets marked: "Remove Covers Before Thermal Test & Flight."
The Skylab urine collector consisted of a urine receiver and hose through which urine passed into a personal urine drawer. Each urine drawer contained a liquid/gas separator (centrifuge), urine bag, sample container, and refrigeration line to cool the separator. At the start of urination, the crewmember actuated the liquid/gas separator, creating a positive airflow at one foot per minute. The airflow separated the liquid fraction of the urine and transferred it into a collection bag inside the urine drawer. Urine was collected in the bag for 24-hour periods. A measured amount of lithium chloride was added to the pooling bag before flight to permit calculation of urine volumes based on lithium dilution. Crew members also used a gage to measure pooling bag thickness. Collected samples were placed in a freezer to return to Earth for scientific study.
