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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.

The XMM-NEWTON satellite is the ESA X-ray spaceborne observatory covering the soft X-ray portion of the electromagnetic spectrum. XMM-NEWTON has been put in orbit on December, 10th 1999 by an Ariane 5 single launch. The spacecraft has a conventional thermal design that takes full advantage of the stable environment provided by its high altitude/long period orbit and by the limited variation of solar attitude angles in order to provide a stable platform for the telescope system. The precise geometry and alignment of the telescope system impose strict temperature requirements so that not only temperature gradients have to be kept small but also, and more importantly, time-variations of the gradients have to be minimised. In the paper, the thermal behaviour of the spacecraft as verified by its thermal test programme is compared with the early in-orbit temperature measurements.

The XMM (X-ray Multi-Mirror) spacecraft is a space-borne observatory for soft X-ray astronomy. It is developed and built under an ESA contract by an industrial consortium led by Dornier Satellitensysteme GmbH. Due to the large dimensions of the whole spacecraft measuring more than 10 m in height and more than 4 m in diameter, it is split into an upper and a lower module for integration and testing. These modules were separately vacuum tested in the Large Space Simulator at ESTEC, allowing for different spacecraft attitudes with reference to the solar simulator beam. This paper reports on the thermal vacuum test of the XMM lower module (LM), which was conducted in January 1999. The successful completion of this test was a further decisive cornerstone in passing the XMM flight acceptance review in late 1999.

Thermal protection systems (TPS) for hypersonic transport vehicles are described and evaluated. During the flight through the atmosphere moderate to high aerodynamic heating rates with corresponding high surface temperatures are generated. Therefore, a reliable light- weight but effective TPS is required, that limits the heat transfer into the central fuselage with the liquid hydrogen tank and that prevents the penetration of the temperature peak during stage separation to the load carrying structure. The heat transfer modes in the insulation are solid conduction, gas conduction, gas convection and radiation. Thermal protection systems based on different phenomena to reduce the heat transfer, like vacuum shingles, inert gas filled shingles, microporous insulations and multiwall structures, are described. It is demonstrated that microporous and multiwall insulations are efficient, light weight and reliable TPSs for future hypersonic transportation systems.