Orbiter Venting Elimination Strategy During Docked Operations to the International Space Station (ISS)

The NASA Orbiter was designed with the ability to store a limited amount of wastewater on board. Due to several factors including the storage capacity of the waste tank, the number of crew members onboard, and the length of a mission, the Orbiter must vent wastewater overboard at regular intervals. During a typical Orbiter mission to the International Space Station (ISS), the Orbiter must vent a significant amount of wastewater at least once during the docked timeframe. A future ISS program requirement that affects the Orbiter while docked, is elimination of wastewater venting, specifically urine, once the Japanese Experiment Module (JEM) is added to the orbiting facility. A working group was developed to address elimination of orbiter wastewater venting with members from both the Orbiter and ISS programs. Multiple options exist to meet this requirement. However, each option requires one or a combination of many sacrifices on the parts of the Mission Operations Directorate (MOD), the Astronaut Office (CB), the Manifest Working Group (MWG), the ISS Trash Working Group (TWG), the Russian Space Agency (RSC-E), the Orbiter Program, and the ISS Program. Each option was evaluated to determine which had the least impact on all affected parties. The ISS Program is still gathering information on the two best solutions, and debating which option will be chosen to collect the volume of wastewater above the Orbiter wastewater tank limit during the determined docked duration time frame. Negotiations, hardware costs including new hardware certification, and crew concerns are all critical factors in this decision. The recommended options for eliminating orbiter venting are defined in more detail within this paper, along with all other options considered in this trade study. Where available, pictures and schematics are used to describe the operation hardware and/or setup.