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Technical Paper

Thermal Design of CryoSat, the first ESA Earth Explorer Opportunity Mission

CryoSat is the first satellite of ESA's Living Planet Programme realised in the framework of the Earth Explorer Opportunity Missions. CryoSat is a radar altimeter mission dedicated to determine trends in the ice masses of the Earth. The overall spacecraft configuration was driven by the budget constraints applicable for the opportunity mission, the high inclination orbit with drifting orbit plane and the stringent stability requirements for the radar altimeter antennas. Innovative thermal design solutions were needed for the following items: The instrument antennas have to comply with very stringent pointing stability requirements. The star trackers need to be mounted at a thermally adverse position and still have to be maintained on low temperature levels.
Technical Paper

New Developed Space Qualified ECLSS Products for the ISS

In the range of the Columbus Orbital Facility (COL) program, the European contribution to the International Space Station (ISS), DASA Dornier developed and qualified four new supporting devices for the Environmental Control and Live Support System (ECLSS) as listed below: 1. The Vacuum & Venting Pressure Sensor (VVPS). Based on the Pirani principle, it utilizes the pressure dependence of the gas thermal conductivity. 2. The Humidity Sensor (HS) provides information for the Thermal & Humidity Control System (THC). It works according to the dew point principle, guaranteeing a long stability over at least 10 years. 3. The Air Flow Sensor (AFS), working according to the hot wire anemometer principle, is dedicated to identify low air flow conditions. 4. The Waste Gas Line Shut-Off Valve (WLSOV), a DC motor driven ball type vacuum valve, was adapted to the space station requirements (e.g. noise and micro-g).
Technical Paper

Development of Automated Transfer Vehicle Cargo Carrier (ATVCC) ECLS Air Distribution System based on the MPLM and COLUMBUS Experience

In 1995 the European Space Agency did award a C/D Contract for the design & development of an ECLS Subsystem for the Multi Purpose Logistics Module (MPLM) to Astrium’s ECLS ‘Center of Competence’ that built the ECLSS for Spacelab already. Actually first MPLM modules were successfully flown to the ISS with the Astrium built ECLSS qualified as ‘excellent’ by the crew having asked permission to sleep in there. In parallel the design and development of an ECLS for Europe’s Columbus module did commence and is actually close to completion. In view of the above a broad set of qualified and even space proven ECLS equipment is now ‘on-hands’ to thoroughly compose respectively derive the ECLS subsystems of future applications e.g. HabModule, CRV and Space Hotel at a limited delta design and validation effort thus fitting into the tighter financial budgets of the manned space programs to come.
Technical Paper

Design for the NIRSpec Optical Assembly Cover

NIRSpec is a near-infra-red spectrometer and one of the four instruments onboard the James Webb Space Telescope (JWST). The JWST observatory will be placed at the second Lagrange point (L2). The instrument will be operated at about 30 Kelvin. Temperature stability and controlled heat rejection to dedicated JWST radiators are important issues of the NIRSpec thermal design. Besides thermal insulation, the NIRSpec Optical Assembly Cover also has to provide light tightness and stray light suppression to prevent unwanted light entering the instrument. Air tightness is needed to allow a controlled purge gas flow for contamination prevention while allowing proper air venting during launch. Because of mass constraints a cover employing two-foil Kapton blankets supported by aluminum posts and a wire tent was chosen. Failure tolerance and cleanliness are other important design drivers. This paper describes the design solutions established to fulfil the contrary requirements
Technical Paper

Cryo Component Test of Herschel EPLM

The Herschel satellite is a space based telescope designed for the investigation of sub millimeter radiation from astronomical objects. The cryogenic system is an essential part of the telescope’s Extended Payload Module (EPLM). The cryogenic system has to provide an environment of sufficiently low temperatures to assure the proper functioning of the scientific payload. Main component of the cryogenic system is the cryostat, a huge vacuum vessel (see: Figure 1) with various cryogenic components inside. In order to qualify the components of the cryogenic system, multiple tests such as leak tests, thermal cycle tests, pressure cycle tests and vibration tests are performed. In this paper the test program for two cryo components, the rupture disc and a safety valve is discussed. The testing philosophy is presented and selected results of tests at ambient and low temperatures are shown.