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Water reclamation from human urine will be the basis of the closed loop Water Recovery Management (WRM) system on Space Station Freedom (SSF). Pretreatment is necessary to collect and process urine, fix and prevent ammonia formation, inhibit microbial growth and prevent solids precipitation. Pretreatment must be accomplished immediately upon collection to prevent damage to urine collection and handling equipment. Currently, a chemical injection scheme is an integral part of the SSF Urinal design. The reagents used will be based on compatibility with Urinal and Urine Processor components, performance of necessary pretreatment functions, quality of reclaimed water, resupply costs and development risks. These factors are compared for various pretreatment methods currently under consideration for use on SSF.

Water reclamation will be the basis of the closed loop Water Recovery Management (WRM) system on Space Station Freedom (SSF). The life support loop is considered “closed” in the sense that water will not be resupplied to SSF, only food with sufficient water percentage to make-up for inefficiencies in recovery, will be resupplied every 90 days. Oxygen will be generated from water. Mass balance for water, atmosphere and solids pertaining to Environmental Control and Life Support Systems (ECLSS) on SSF has been modeled on a Lotus 123 spreadsheet. Pictoral and numerical representations of the mass balance is shown in Figures 1, 2 and 3 for Manned Tended Configuration (MTC), Permanently Manned Configuration (PMC) and Eight Man Capability Configuration (EMCC), respectively. Parameters are varied to analyze the sensitivity of the mass balance to different hardware combinations, crew configurations and metabolic rates.

Exhaustive testing and analysis of Vapor Compression Distillation technology has proven its overall readiness as a wastewater processor for the recovery of water in orbiting and interplanetary spacecraft. In conjunction with Boeing Aerospace and Electronics and the National Aeronautics and Space Administration, Life Systems' technical team has been focusing on verifying and improving performance characteristics, micro-gravity compatibility, reliability and maintainability aspects of the Vapor Compression Distillation design. Amassing thousands of hours of testing and recent breakthroughs in the area of peristaltic pump design, product water conductivity sensing and gas/liquid separation concepts have substantially increased the engineering and scientific database that has been accumulating over the past 29 years.

The Fluid Systems Servicer (FSS) is designed to drain, purge, fill, and recirculate fluids while performing on-orbit start-up, scheduled, and unscheduled maintenance for fluid lines on the International Space Station (ISS). The FSS will utilize space vacuum for purging operations, thus, providing essentially unpowered vacuum back-filling capability. There is also a fluids pump in the FSS which is used for draining and recirculating water. The recirculation mode fulfills an additional design requirement of removing gas bubbles by directing water through a static membrane separator. Several flex-lines and adapters which interface various ISS lines via self-sealing Quick Disconnects (QD), are part of the FSS assembly. The FSS has its own power cord enabling excellent transportability. This feature, as well as, the QD adapters, enables the FSS to be used anywhere on station for numerous servicing tasks.

The Fluid Systems Servicer (FSS) is designed to drain, purge, fill, and recirculate fluids while performing on-orbit start-up, scheduled and unscheduled maintenance for fluid lines leak check ports, and window assemblies on the International Space Station (ISS). The FSS will undergo extensive functional testing to verify that all design requirements have been met. The FSS will utilize space vacuum for purging operations on-orbit, thus providing vacuum back-filling capability with minimal power consumption. For ground testing, the application of space vacuum will be simulated. A full scale mock-up of the Space Station 20″ Window Assembly has been built for requirements verification. Two desiccator assembly Orbital Replacement Units (ORU)s will be tested to assure the FSS can perform window servicing requirements. The FSS gas/liquid separator fulfills an additional design requirement of removing gas bubbles from fluids with a static membrane separator.

Vapor Compression Distillation technology for phase change recovery of water from wastewater has evolved as a technically mature and energy efficient approach for meeting the National Aeronautics and Space Administration mission needs/goals for the near-term Space Station Freedom Program and future advanced missions such as a Lunar Base and Mars exploration. Water is essential not only for the survival of humans in space, but also for efficient and economical operation for various space stations. Life Systems, Inc., in conjunction with the National Aeronautics and Space Administration, has been developing the Vapor Compression Distillation Phase Change Concept. During the development of this technology over the past 17 years an extensive engineering and scientific database has been assembled.

Space Station Freedom (SSF) will be required to vent water during non-quiescent periods. During Man Tended Configuration (MTC), before the Environmental Control and Life Support System (ECLSS) water loop is closed, humidity condensate will be periodically vented. At Permanently Manned Configuration (PMC), water will be vented on contingency if there is excess water on SSF. The thrust due to venting must be minimized to be considered non-propulsive. Also, ice formation and clogging of the vent nozzle must be avoided. Many aspects of the Space Shuttle water vent design were utilized in development of the preliminary SSF water vent design presented in this paper. Design modifications which improved the shuttle vent as well as those necessary for SSF are discussed. The exterior vent location, direction and environment on SSF are unique compared to previous space water vent designs. From data collected in the vent tests and analyses, a finalized SSF water vent design will be developed.

Alkyl silane amphiphiles form robust Self-Assembled Monolayers (SAMs) on stable oxide surfaces. Substrate surfaces of Ge, Si, and Ti can be modified by coating them with ultra-thin long-chain alkyl silane monolayers which are found to be very stable1. Titanium is especially interesting as it is a light, corrosion-resistant metal used in aircraft, spacecraft, and medical devices. In this study, mixed monolayers, composed of very similar alkyl silanes, differing only in chain length by about 5 angstroms (Å), were formed on silicon wafer substrates. Although the desired and expected result was random mixing of the monomers in the SAM, island aggregates of the longer monomer were observed with Atomic Force Microscopy (AFM). Since self-assembly of silanes on oxide is believed to be attained through strong covalent Si-O bonding at the substrate surface, inter-molecular thermodynamic forces between like molecules, or incomplete mixing of monomers may give rise to island formation.

There is an assortment of hardware designed to work together to provide fluid servicing, seal leak checking and other plumbing-type services on the International Space Station (ISS). The Fluid Systems Servicer (FSS) is designed to drain, purge, fill, and recirculate fluids for on-orbit start-up, scheduled and unscheduled maintenance. The FSS will utilize space vacuum for purging operations on-orbit via the Vacuum Access Jumpers (VAJ), thus providing vacuum back-filling and static leak check capability with minimal power consumption. The FSS services Internal Thermal Control Systems (ITCS) and Environmental Control & Life Support (ECLS) System hardware in the pressurized elements of the ISS. The FSS gas/liquid separator fulfills an additional design requirement of removing entrained gas from fluids by means of a static membrane separator. The FSS and some ancillary equipment also perform Seal Leak Check (SLC), pressure removal and equalization, and window assembly maintenance on ISS.