A system on a chip concept for the Mercury Thermal Imaging Spectrometer MERTIS

A very advanced Mercury Thermal Infrared Spectrometer (MERTIS) was proposed by the German Aerospace Center (DLR) fulfilling the extreme resource restrictions of the ESA deep space mission BepiColombo to the inner planet Mercury. The design drivers for the MERTIS instruments are the limited mass and the harsh radiation environment. Derived from these main constrains are power-, volume- and thermal restrictions. This paper presents some key technologies applied to keep the BepiColombo mission limits. It will touch the extreme light weight and compact optic design but focuses on the system on a chip application of the MERTIS instrument digital electronics and its influence to the system structure and reliability concept. It will further show some techniques making the operation of the MERTIS instrument more robust in this radiation exposed environment. One example is the integration of a digital thermal controller for a thermo electrical cooler with less than 10 mK accuracy. It is synthesized into the MERTIS system on a chip instrument controller based on a field programmable gate array (FPGA).