DEVELOPMENT OF A SOLID STATE MULTIPLEXER DATA COLLECTION UNIT FOR THE ESTEC LARGE SPACE SIMULATOR

摘要

The testing division of the European Space research and Technology Center (ESTEC) upgraded its TEMPerature Data Acquisition System (TEMPDAS) of the Large Space Simulator (LSS). The LSS is a facility that provides close simulation of in-orbit environmental conditions for spacecraft and payloads testing. It is equipped with a Motion System (MS), which allows spin, rotation and attitude positioning of test objects. The presence of a Slip-Ring-Unit (SRU) located in the Spin-box makes it possible to transmit, amongst others, signal generated by thermocouples fixed on a rotating test object (e.g. the structural-thermal model of a spacecraft) to the local Data Handling System. The TEMPDAS consists of two Data Collection units (DCUs) placed inside the LSS and a serial redundant Data Handling Unit (DHU) located outside the LSS. DCU(s) and DHU communicate via the serial redundant bus MIL-1553-B. The inputs stage of the existing DCU is characterised by a multiplexer based on relays which have the capacity to acquire up to 432 thermocouple channels. In order to improve the reliability of the front end unit, a new equipment called the Solid State Multiplexer Data Collection Unit (SMDCU) has been developed. The SMDCU will be integrated in the LSS and shall operate at extreme temperatures under vacuum, as the LSS provides close simulation to in-orbit environmental conditions for the purpose of spacecraft testing.