The SMOS satellite is a polar-orbit sun-synchronous Earth observation ESA mission, whose science objectives are to:
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globally monitor surface soil moisture over land surfaces,
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globally monitor surface salinity over the oceans, characterise ice and snow covered surfaces
The SMOS satellite is composed of the Proteus platform and the Payload module/MIRAS instrument.
This paper is dedicated to the thermal design and testing of SMOS payload module (PLM).
The PLM thermal design is passive, maximizes the use of proven materials and processes and is supported by heaters.
The major drivers for the design are the limitation in heater power allocation and the stringent temperature requirements.
The verification of the PLM thermal design is based on a Thermal Balance (TB) testing of a Structural Thermal Model (STM), followed by a TB/TV test on the ProtoFlight Model (PFM). A Thermal Vacuum (TV) test has also been performed for the complete spacecraft.
The PLM test objectives, the test phases and the requirements for the test environment lead to a unique test setup with an MGSE designed to deploy the payload inside the facility and to test it at different orientations relative to the Sun.