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This paper discusses the thermal modeling activities as a design and development tool for the Tracker Thermal Control System, the mechanically pumped, carbon dioxide thermal management system for the AMS-2 Silicon Tracker. Main modeling topics are: radiator sizing and condenser development, set-point control and pre-heating issues with respect to the spatial and temporal temperature gradient requirements of the Tracker.

Mechanically and capillary pumped two-phase heat transport systems are currently developed to meet the high power and long transport distance requirements of thermal management systems for future spacecraft. As two-phase flow and heat transfer in a low-gravity environment is expected to (considerably) differ from terrestrial behaviour, the technology of two-phase heat transport systems and their components has to be demonstrated in orbit. Therefore a Dutch-Belgian two-phase experiment (TPX) is being developed within the ESA In-Orbit Technology Demonstration Programme TDP1. TPX concerns a two-phase ammonia system in the (5ft3, gaseous nitrogen filled) Get Away Special canister G-557. The system is a downscaled capillary pumped two-phase loop. It includes downscaled versions of mechanically pumped two-phase loop components: multichannel condensers and vapour quality sensors (plus a controllable 3-way valve for control exercises). The Critical Design Review status of TPX is discussed.

As two-phase flow and heat transfer is expected to strongly depend on the gravity level, a Two-Phase eXperiment has been developed for ESA to demonstrate two-phase heat transport system technology in orbit. TPX, a reduced-scale capillary pumped two-phase ammonia loop with a flat and a cylindrical capillary evaporator and an actively controlled reservoir for loop temperature setpoint control, included downscaled components of mechanically pumped loops: multichannel condensers, vapour quality sensors, and a controllable 3-way valve for vapour quality control exercises. The presented detailed evaluation of the experiment results obtained during the TPX flight on STS60, clearly proves the viability of two-phase technology for space.

Mechanically and capillary pumped two-phase heat transport systems are currently developed to meet the high power and long transport distance requirements of thermal management systems for future spacecraft. Compared to existing single-phase systems, two-phase loops offer important advantages: reduced overall mass and pumping power consumption, virtually isothermal behaviour, adjustable working temperature, insensitivity to variations in heat load and sink temperature, and high flexibility with respect to the location of heat sources within the loop. As two-phase flow and heat transfer in low-gravity environment is expected to (considerably) differ from terrestrial behaviour, the technology of two-phase heat transport systems and their components is to be demonstrated in orbit. Therefore a Dutch-Belgian Two-Phase experiment has been developed within the ESA In-Orbit Technology Demonstration Programme.

Mechanically pumped two-phase heat transport systems are currently developed to meet the high power and long transport distance requirements of thermal management systems for future large spacecraft. Capillary pumped systems are being developed for applications with special requirements concerning microgravity disturbance level, temperature stability and controllability. As two-phase flow and heat transfer in a low-gravity environment is expected to differ from terrestrial behaviour, two-phase heat transport system technology has to be demonstrated in orbit. Therefore the Dutch-Belgian Two-Phase eXperiment TPX has been developed within the ESA In-Orbit Technology Demonstration Programme. TPX is a two-phase ammonia system, flown in the 5ft3 gaseous nitrogen filled Get Away Special canister G557, aboard STS-60.