The MErcury Radiometer and Thermal Infrared Imaging Spectrometer (MERTIS) is an instrument to study mineralogy and temperature distribution of Mercury surface in unprecedented quality. MERTIS was proposed in 2003 as payload of the Mercury Planetary Orbiter spacecraft of ESA-JAXA BepiColombo mission and will reach Mercury in 2026. MERTIS will map the whole surface at 500m resolution combining a push-broom IR grating spectrometer (TIS) with a radiometer (TIR) sharing the same optics, instrument electronics and in-flight calibration components for the whole wavelength range of 7-14μm (TIS) and 7-40μm (TIR). Currently we are developing and testing an ingestion, calibration and transformation pipeline for MERTIS data, from raw telemetry level data to calibrated product and high level derived product. Bepicolombo Science Ground Segment (BC-SGS or SGS) is embracing new technologies for the BepiColombo mission and follows the latest NASA/PDS format, the xml based PDS4. We adopt open source languages and well optimized libraries for the underlying processing. The data processing pipeline is fully containerized via Docker to be independent from transition between server/OSs/environment, drastically reducing the integration and testing time. Due to strict infrastructural constrains like spacecraft downlink bandwidth and onboard mass memory, the already complex observation scenario is subject to further optimizations. This complicates the reconstruction process for higher-level products like global maps of emissivity and thermal inertia.
The Planetary Spectroscopy Laboratory (PSL) of DLR in Berlin provides spectral measurements of primarily planetary analogues from the visible to the far-infrared range. PSL has supported the data analysis as well as the development and calibration of instruments for planetary missions from ESA, NASA and JAXA. For this purposes PSL provides reflection, transmission and emission spectroscopy of target materials. Currently PSL operates two identical Bruker Vertex 80V vacuum FTIR spectrometer, one spectrometer is equipped with aluminum mirrors optimized for the UV, visible and near-IR, the second features gold-coated mirrors for the near to far IR spectral range. External simulation chambers are attached to each of the instruments for emissivity measurements. The chamber at the near to far IR instruments allows emissivity measurements from 0.7-200 μm under vacuum for sample temperatures from 320K to above 900K, using an innovative induction system. The second chamber (purged with dry air and water cooled to ≤270K) allows emissivity measurements of samples with surface temperature from 290 to 420K. We measure bi-directional reflectance of samples, with variable incidence and emission angles between 13° and 85°. Samples are measured currently at room temperature and 170K, with a planned extension for temperatures below 100K. Bi-directional and hemispherical reflectance is measured under purging/vacuum conditions, covering the 0.2 to above 200 μm spectral range. Transmission of thin slabs, optical filters, optical windows, pellets, and others is measured in the complete spectral range from UV to FIR using a parallel beam configuration to avoid refraction.
TROTIS (TROjan asteroid Thermal Infrared multi-Spectral imager) is a high spatial-resolution thermal imaging system optimized for targets in the outer solar system with heritage from the Miniaturized Asteroid thermal infrared Imager and Radiometer (MAIR) for the AIDA mission as well as Bepi-Colombo mission's MErcury Radiometer and Thermal Infrared Spectrometer (MERTIS). TROTIS will provide unique science observations that will foster our understanding of Trojan asteroids. It will provide compositional information, thermal physical properties as well as help determine accurate shapes. In addition TROTIS can aid optical navigation, as it will be able to detect targets from any phase angle.
The MErcury Radiometer and Thermal infrared Imaging Spectrometer (MERTIS) is a highly integrated instrument to study mineralogy and temperature distribution of Mercury’s surface in unprecedented quality. MERTIS was proposed in 2003 as payload of the Mercury Planetary Orbiter spacecraft of the joint ESA-JAXA BepiColombo mission. With the planned launch on top of an Ariane 5 in October of 2018, the mission will soon start its 7 years journey to Mercury. On its way to Mercury, BepiColombo will have 2 flybys of Venus and one of the Earth-Moon system. MERTIS will obtain data during each of these flybys – for Venus the first mid-infrared spectral data since Venera 15 in 1983. After arrival at Mercury in 2025 MERTIS will globally map the surface composition with a resolution of 500m, and study surface temperature variations providing an insight into the thermo-physical properties of the surface. To achieve this, MERTIS combines a push-broom IR grating spectrometer (TIS) with a radiometer (TIR) sharing the same optics, instrument electronics and in-flight calibration components for the whole wavelength range of 7-14 μm (TIS) and 7-40 μm (TIR), respectively. Instrument operations in the challenging environment at Mercury with power and data constraints require a sophisticated mapping scheme for the TIS observations, which also has to account for the MERTIS calibration needs. Execution of this scheme creates challenges for the operation of the instruments, data processing, and the creation of map products. Extensive onground testing and rehearsals during the Venus and Earth flybys will ensure flawless performance at Mercury.