Search Results

Methane-filled heat pipes have been developed and qualified for the SCIAMACHY thermal bus assembly. The heat pipes provide an efficient heat transfer in the temperature range 100-160 K. Extensive qualification testing has been performed. The thermal bus assembly is part of the Thermal Bus Unit (TBU) of the SCIAMACHY Radiant Cooler.

Flexible thermal links are necessary to couple thermally but flexibly instrument sensors to their heat sink. Three promising flexible thermal link design concepts are described and investigated, the braided solid conductor made of metallic foils, the spring-shaped axial grooved heat pipe and the carbon fibre thermal link. The design principles of those concepts are presented. Advantages, drawbacks and critical points are analyzed and typical performance data are reported. This work includes also results from mechanical and thermal tests performed on various flexible thermal link samples. The investigations reveal, that braided metallic conductors can cover the widest range of applications. However, for a certain range of applications, the spring-shaped heat pipe and the carbon fibre link are valid alternatives with significant improvement of the thermal conductance associated with lower mass and similar mechanical performance.

Herschel is an ESA scientific satellite with a cryogenic payload for astronomical infrared observations, to be launched in 2007. The thermal control system of the Herschel Extended Payload Module (EPLM) shall provide a 1.65 K heat sink for 3.5 years mission lifetime. The major parts of the EPLM are the Cryostat Vacuum Vessel (CVV), the Herschel Solar Array and Sunshade (HSS) and the 3.5 m Telescope. The CVV contains a 2367 ❘ superfluid Helium tank and the Optical Bench, which carries the three scientific instruments. The CVV also carries the Telescope and the Local Oscillator Unit (LOU) used for one scientific instrument. Furthermore, the CVV is equipped with external radiators and internal vapour-cooled shields. The EPLM is mounted on top of the Herschel Service Module (SVM). In addition, a thermal shield is arranged between SVM and CVV. This paper describes the EPLM thermal design and the main thermal analysis results for operation on ground and in orbit.