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This paper presents a novel method and system for an electric power alternating-current (AC)-to-direct-current (DC) converter employing composite technology. The term composite entails utilization of more than one type of conversion operating in parallel. In addition, background information for the prior art, based on conventional autotransformer rectifier units (ATRUs), and active converters are discussed. The major requirements of AC-to-DC converters from both functional and protection perspectives are provided. The concept of the new approach is defined. Comparative analysis between the new and old methods is documented. The performance features and technical details of the system parameters with respect to AC-to-DC converter system requirements are presented and discussed. Analysis, simulation results, and test data are included. Finally, the advantages of this technology, which nearly doubles power density compared to the state-of-the-art, are summarized and a conclusion included.

Since the 1960s, aerospace research and development (R&D) has been on a quest to eliminate oil lubrication systems from gas turbine engines. Beginning with small solar power dynamic “engines” for space applications, U.S. Government and industry have invested millions of dollars to mature this technology for incorporation into modern aircraft propulsion engines. This paper traces the evolution of oil-free rotor support systems that have actually been tested in advanced demonstrators, and the technology that enables this revolutionary engine configuration. However, this technology has yet to be fielded in aerospace products. The key factors of 45 years of Government and industry R&D and a vision to mature oil-free gas turbine engines are presented herein.

The first concept and early experiments of a mechanical counter pressure (MCP) spacesuit were published by Webb in the late 1960's. MCP provides an alternative approach to the conventional full pressure suit that bears some significant advantages, such as increased mobility, dexterity, and tactility. The presented ongoing research provides a thorough investigation of the physiological effect of mechanical counter pressure applied onto the human skin. In this study, we investigated local microcirculatory effects produced with negative and positive ambient pressure on the lower body as a preliminary study for a lower body garment. The data indicates that the positive pressure was less tolerable than negative pressure. Lower body negative and positive pressure cause various responses in skin blood flow due to not only blood shifts but also direct exposure to pressure differentials.

The cascaded distiller CD5 is a 5-stage, rotary vacuum distiller developed jointly by Honeywell International (USA) and Thermodistillation Co. (Kiev, Ukraine) for processing of human urine and other streams of waste water onboard a spacecraft during long-duration missions. Initial performance testing of the first model of the distiller CD5-1 was conducted at the Thermodistillation laboratory in Kiev in 1999. Results of testing demonstrated superior performance of the machine, but also indicated that performance could be improved. This paper reports on performance of the next generation of the distiller, CD5-2, which is an improved model of the cascaded distiller CD5-1.

Carbon dioxide removal is an essential part of any environmental control and life support system of an enclosed atmosphere. The current state of key technology is the existing International Space Station (ISS) Carbon Dioxide Removal Assembly (CDRA) used to selectively remove carbon dioxide from the cabin atmosphere. The CDRA is part of the ISS air revitalization system. This paper will present approaches to recover the carbon dioxide for down stream processing. A discussion of a closed-loop CDRA system that will selectively remove carbon dioxide from the cabin air supply and this product will be routed to a carbon dioxide reduction system, where the oxygen will be recovered. Using a CDRA system modified for closed loop operation, a case by case illustration of the sequential operation will be presented.