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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.

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.

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.

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.

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.