Search Results

Vapor Compression Distillation (VCD) technology for phase change recovery of potable water from wastewater has evolved as a technically mature approach for use aboard the Space Station. A program to parametrically test an advanced preprototype Vapor Compression Distillation Subsystem (VCDS) was completed by Life Systems for the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) during 1985. In parallel with parametric testing, a hardware improvement program was initiated to incorporate and verify certain key improvements into the advanced preprototype VCDS following initial parametric tests. Specific areas of improvements included long-life, self-lubricated bearings, a lightweight, highly-efficient compressor and a long-life magnetic drive. These improvements are now incorporated and verification testing started.

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.

Disinfection of water and wastewater was proven to be feasible using a Breadboard Electrochemical Ozone Generator (EOG). A static gas/liquid separator, containing a microporous, hydrophobic membrane, was tested with the Breadboard EOG, and was found to increase the concentration of the ozone (O3) dissolved in the water. Distilled water and selected wastewaters were disinfected, achieving dissolved O3 concentrations up to 3 mg/L. The hardware is capable of operating in 0-g and 1-g environments. An end-item Electrochemical Ozonator (EO), sized to disinfect 116 kg of potable water per day, was projected to weigh 1.2 kg and consume only 18.5 W.

Progressive development of Electrochemical Carbon Dioxide (CO2) Concentration (EDC) technology by Life Systems under the sponsorship of the National Aeronautics and Space Administration (NASA) has resulted in subsystem hardware and Control and Monitor Instrumentation (C/M I) that are ideally suited for application to the Space Station program. The development effort has simplified the mechanical assembly to where only seven Orbital Replacement Units (ORUs), including two integrated components, are required to perform the process function. This simplification results in subsystem weight, power and volume requirements that are less than those of competing technologies. Further, process simplification provides both superior reliability and enhanced maintainability. Control and Monitor Instrumentation development has focused on utilization of state-of-the art electronics and software features that enhance subsystem reliability through fault detection and isolation.

Vapor Compression Distillation technology has proved its readiness as a spacecraft wastewater processor as evidenced by selection of this technology for the Urine Processor Assembly aboard Space Station Freedom. In conjunction with Boeing Aerospace Company and the National Aeronautics and Space Administration, Life Systems' technical team has made significant advances in both flight hardware design and software operational aspects. The flight hardware design has focused on Orbital Replacement Unit (ORU) design, ORU rack packaging and ORU weight reduction. On orbit operational aspects of software include operating modes, process control loops, fault detection and fault isolation. These improvements are further indication that Vapor Compression Distillation will be the key to providing wastewater regeneration essential for long-term human survival in space.

Cooperation between Russia and the United States on manned spaceflight has led to unprecedented openness, resulting in the ability to now compare the characteristics of environmental control/life support hardware selected to generate oxygen (O2) by water electrolysis for space station applications. This comparison in this paper focuses on the characteristics that have the greatest effect on the cost of assembling and maintaining the hardware in space: launch weight, volume, power consumption, resupply requirements and maintenance labor.