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After the launch to the International Space Station with The Space Shuttle flight STS 118 13A.1 on August 9th 2007 and the accommodation in the US lab Destiny, the air quality monitor ANITA (Analyzing Interferometer for Ambient Air) has been successfully put into operation. ANITA is a technology demonstrator flight experiment being able to continuously monitor with high time resolution the air conditions within the crewed cabins of the ISS (International Space Station). The system has its origin in a long term ESA (European Space Agency) technology development program. The ANITA mission itself is an ESA-NASA cooperative project. ESA is responsible for the provision of the HW (Hardware), the data acquisition and data evaluation. NASA's responsibilities are launch, accommodation in the US Lab Destiny, operation and data download.

After 11 months of successful operation onboard the ISS US laboratory Destiny, the air quality monitors ANITA (Analyzing Interferometer for Ambient Air) was brought back to Earth on STS126 (ULF2). ANITA is a technology demonstrator flight experiment for continuous air quality monitoring inside the crewed cabin of the ISS with low detection limits and high time resolution. For the first time, the dynamics of the detected trace gas concentrations could be directly resolved by ANITA and correlated to gas events in the cabin. The system is the result of a long term ESA technology development programme initiated more than seventeen years ago. The ANITA mission was a cooperative project between ESA and NASA. ESA's responsibilities were the provision of the H/W, the data acquisition and the data evaluation. NASA was responsible for the launch, accommodation and operation onboard ISS, data download and the transportation of ANITA back to the Earth.

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.

Based on the thermal requirements of future large European platforms such as the Columbus Space Station, several developments in the field of two-phase flow systems were initiated over the last few years in Europe. This paper will give a general overview of the objectives, development status and test results of an ESA-funded ‘Two-phase heat transport system’ study and of two studies sponsored by the German Ministry of Research and Technology on two-phase heat transport. The ESA two-phase loop system resulting from the concept trade-off is driven by an electrically powered liquid pump and is provided with a capillary cold plate and an evaporative heat exchanger mounted in parallel. Under certain conditions, a simplified version of this type of system is able to work in a capillary-pumped mode. The system is designed for a heat load of 10-20 KW, a length of 20 m, a working temperature around 20°C and R114 as working fluid.

A cryogenic liquid trap heat pipe diode with methane as working fluid has been studied experimentally. The test set-up consists of a vacuum chamber to accomodate the instrumented diode, power sources for the different heaters attached to the diode, a nitrogen-vapor cooling system and a data acquisition unit. The experimental program included measurements of the maximum forward mode performance vs. operating temperature, measurements of the maximum forward mode performance vs. working fluid fill charge and investigations of the transient shut-down behaviour of the diode.

As it is not possible to directly use commercial liquid flow meters in spacecraft fluid loops, a study was carried out for the European Space Agency to adapt commercial flow meter assemblies for space applications. The various activities (described in detail) eventually led to the selection of two commercial units, which were redesigned/adapted to be used in spacecraft single-phase (water) and two-phase (ammonia) thermal control loops. These flow meter assemblies were tested according to an agreed test programme, that included performance and calibration tests in a test bench (developed during the study), vibration testing and EMC/EMI testing. The results are discussed in order to assess to what extent the study objectives were met. Recommendations for future work are given also.