Design of the MERTIS Pointing Unit for BEPI COLOMBO mission

Design of the MERTIS Pointing Unit for BEPI COLOMBO mission
Mirosław Rataj, Robert Pietrzak, Piotr Wawer, Piotr Orleański
Centrum Badań Kosmicznych PAN,

Abstract
The Mercury Radiometer and Thermal Imaging Spectrometer (MERTIS) of the BEPI COLOMBO mission is dedicated to global mineralogical mapping and measurements of Mercury’s surface temperatures in the spectral range of 7-14 μm.
MERTIS Pointing Unit (MPOI) is a mechanism situated in front of MERTIS/BEPI COLOMBO spectrometer to orient the optical entrance of the instrument to 4 different targets sequentially.
MPOI should fulfill very demanding requirements of pointing accuracy and repeatability in whole operating temperature range from –30°C to +70°C. In this paper MPOI’s design and principles of operation are presented. Bepi Colombo started on 20 October 2018 from European’s space port in Kourou. MERTIS instrument has successfully passed tests on orbit during commissioning phase.