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Future large spacecraft such as the Space Station will have high power dissipations and long heat transport distances. The combination of these two requirements dictate the need for a new heat transport technology. NASA-JSC has developed the concept of a two phase thermal bus in which the working fluid is evaporated at the heat collection site and is condensed at the heat rejection site. This provides a nearly isothermal system at lower pumping powers than current single phase systems. Boeing has developed a two-phase thermal bus testbed using ammonia working fluid. This testbed uses a Sundstrand rotary fluid management device (RFMD) to provide fluid pumping and liquid-vapor phase management. Overall heat transport capacity is 25 kW. This internally funded testbed is being used for thermal bus heat exchanger characterization and critical component life tests in an ammonia environment. Currently, the testbed has been assembled, proof-pressure tested, leak tested, and checked out.

General plans for testing of a regenerative ECLS system in a Module Simulator at MSFC have been been discussed in a previous paper; preliminary test results are given in this paper and a companion by Mr. McAlister. Subsystems for this series of tests have been provided by Life Systems, Inc., AiResearch Manufacturing Co., Umpqua Research Company, Lockheed, and Hamilton Standard. Results of testing those subsystems provided by Hamilton Standard are covered in the other paper. Subsystems have been installed in the Module Simulator in accordance with the test plan. These include the 4-bed Molecular Sieve, the Static Feed Water Electrolysis Subsystem, and the Urine Pretreatment/Mixing Unit to be covered herein.

As the missions of the Space Station expand in the servicing and maintenance areas, the potential for long duration and repetitive EVA increases. This increased EVA potential motivates consideration of advanced EVA enclosure concepts. This paper discusses a concept for an EVA enclosure which combines features of the Extravehicular Mobility Unit (EMU) and the Manned Maneuvering Unit (MMU) and incorporates aspects of robotic technology. The pros and cons of using such a unit as well as design and development considerations are discussed.

Life sciences research in the Space Station era will provide an enhanced opportunity for studying gravitational biology. This will be made possible by extending the duration of research from a few days on the current space transportation system (STS) Spacelab to almost unlimited duration in a Space Station laboratory setting. Plants and animals will be used extensively in studying gravitational phenomena. In many instances animal models will be used to study human responses to prolonged space flight where invasive techniques are required. New hardware developments will be necessary to accommodate plant and animal species in a long-duration facility. This is especially true for the plant and animal confinement systems, centrifuge (artificial gravity) systems, and cleaning and washing facilities for cages and enclosures. This paper discusses these technology development items and the critical issues that need to be solved.

A program has been initiated to develop a single set of man/system integration standards, requirements, and guidelines to design hardware and systems with which the space missions crew will interact. This paper describes the background, key issues, and methodology to be used in developing these standards. Included in the methodology is data collection and requirements analysis as well as technical monitoring and review, which includes a government/industry technical advisory group. This paper also briefly describes work performed on the Space Station Human Productivity study.

A family of standardized avionics enclosures has designed, fabricated and tested. These enclosures accommodate Standard Avionics Module circuit cards which utilize aluminum base plates and are cooled by conduction to their mounting guiderails in the enclosure. The guiderails incorporate high performance module clamps and state-of-the-art brazed-fin heat exchangers for air cooling. The enclosures are designed to be cooled by air delivered from an aircraft environmental control system. Cooling effectiveness and enclosure thermal performance have been determined by laboratory tests. Typically, the enclosures provide 85°C (185°F) module edge temperatures while operating with 27°C (80°F) cooling air in a 71°C (160°F) ambient environment. With an operating pressure loss of 374 Pa (1.5 inches of water), their outlet cooling air temperature approaches 71°C (160°F). This results in cooling effectiveness of about 22.7 g/s (3 lb/min) of cooling air per kW.

A series of thermal analyses and tests have been conducted on several avionic enclosures, or “black boxes”, with the enclosure designs being representative of those covered under a new Air Force standard. As a part of this effort, the thermal characteristics of various state-of-the-art hardware elements were investigated, including their effect on overall enclosure thermal performance. Using this data, analyses and tests were then carried out on complete enclosures, with the results indicating that power levels up to 1 watt/in3 could be achieved without exceeding device junction temperature limits.

This paper details the development of standardized avionic enclosures for Naval aircraft, with particular emphasis on the package’s thermal design. The packaging system is unique in that it can accommodate modules of two different standardized sizes (ISEM-2A and 1/2 ATR), and modules having three different cooling modes -conduction cooled, flow-through cooled, and heat pipe cooled. The three module cooling modes, together with required package dissipation rates of 125 watts/MCU and pressure drops below 2.8 mm mercury create a great deal of complexity in the optimization of the thermal system. A computerized optimization program was therefore utilized to achieve specific designs, with results reported for various module mixes and heat exchanger designs.

The Boeing AMST prototype is a unique design aimed at meeting the goals set by the Air Force for the modernization of tactical airlift. The rationale for the major configuration decisions is reviewed in this paper. Meeting the production cost constraint, one of the most challenging goals, demanded a new design approach aimed at part commonality, in addition to a simplified structural arrangement. The possibility of a commercial derivative of the AMST is reviewed and a proposal made for the use of a small AMST fleet to demonstrate the market potential and the feasibility of short field commercial operation.