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A condensing heat exchanger and filter assembly (CHXFA) has been developed by SECAN / AlliedSignal under a contract from Daimler-Chrysler Aerospace, Dornier, as a part of a European Space Agency program. The CHXFA is part of the Environmental Control and Life Support System (ECLSS) of the Columbus Orbital Facility (COF), the European Laboratory Module of the International Space Station (ISS). The CHXFA contains a filter to remove particulates from the air stream, and a differential pressure sensor to monitor pressure drop across the filter. Parallel condensing heat exchanger cores reduce the air temperature and absolute humidity level. Efficient air-water separation is achieved by a combination of a hydrophilic coating on the heat exchanger air flow passages and a water removal section. A thermal control valve regulates the temperature of the outlet air. A sensor to detect liquid carryover in the air stream is located downstream of the CHXFA.

Advances in carbon dioxide removal technology for spacecraft air revitalization promise to reduce the size and power consumption of carbon dioxide removal systems on future space missions. AlliedSignal has developed a Functionalized Carbon Molecular Sieve (FCMS) that can simultaneously remove carbon dioxide and water vapor. A thermally-coupled pressure-swing adsorption system has been designed using FCMS as the sorbent to provide regenerative carbon dioxide removal. The low regeneration temperature of FCMS results in lower power consumption than is required for conventional adsorbents, which typically desorb carbon dioxide at higher temperatures. The thermally-coupled pressure-swing system was tested, and results were compared to the Space Station Carbon Dioxide Removal Assembly (CDRA) as a reference design. The comparison indicated that a thermally-coupled pressure-swing system with FCMS offers significant savings in mass, volume and power consumption.

An evaporative heat sink has been designed and built by AlliedSignal for NASA's Johnson Space Center. The unit is a demonstrator of a primary heat exchanger for NASA's prototype Crew Return Vehicle (CRV), designated the X-38. The primary heat exchanger is responsible for rejecting the heat produced by both the flight crew and the avionics. Spacecraft evaporative heat sinks utilize space vacuum as a resource to control the vapor pressure of a liquid. For the X-38, water has been chosen as the heat transport fluid. A portion of this coolant flow is bled off for use as the evaporant. At sufficiently low pressures, the water can be made to boil at temperatures approaching its freezing point. Heat transferred to liquid water in this state will cause the liquid to evaporate, thus creating a heat sink for the spacecraft's coolant loop. The CRV mission requires the heat exchanger to be compact and low in mass.

Space environmental control systems must control cabin temperature and humidity. This can be achieved by transferring the heat load to a circulating coolant, condensing the humidity, and separating the condensate from the air stream. In addition, environmental control systems may be required to remove particulate matter from the air stream. An assembly comprised of a filter, a condensing heat exchanger, a thermal control valve, and a liquid carryover sensor, is used to achieve all these requirements. A condensing heat exchanger and filter assembly (CHXFA) is being developed and manufactured by SECAN/AlliedSignal under a contract from Dornier Daimler-Benz as part of a European Space Agency program. The CHXFA is part of the environmental control system of the Columbus Orbital Facility (COF), the European laboratory module of the International Space Station (ISS).