The Modular Infrared Molecules And Ices Sensor (MIRMIS): An Instrument Visiting A Long-Period Comet

The Comet Interceptor mission, selected in 2019, is an ESA’s first F-class mission. It will be the first to visit a (yet-undiscovered) long-period comet or interstellar object. These objects are expected to be “pristine” having not been exposed to the Sun in the inner Solar System. A long-period comet may therefore preserve some of the most primitive material from the early solar system’s history. The mission will launch 3 spacecraft (main spacecraft A and 2 probes: B1 and B2) to the L2 Earth-Sun Lagrange point in which it will wait for a suitable target. The MIRMIS spectrometer is one of the instruments on board of Comet Interceptor mission. It is a collaboration between University of Oxford (UK) and VTT (Finland) as well as scientists from the University of Helsinki, NASA’s Goddard Space Flight Centre, University of Lyon and Southwest Research Institute. The instrument will map the ice and mineral composition of the target nucleus, it will provide characterisation of the gas coma, as well as the distribution of the surface temperatures of the comet nucleus. The spectrometer is composed of 3 moduels covering the spectral range of 0.9 to 25 µm. The Near and Mid Infrared modules (NIR/MIR) will measure spectra in the 0.9 to 5 µm, providing information on volatile species, such as water, CO, CO2 and organics. The Thermal Infrared Imager (TIRI), built at University of Oxford, will map the temperature and composition of the nucleus in the range of 6 to 25 µm, providing key information on the surface and near sub-surface thermal physical properties (e.g. cold traps, boulders/powdered regolith). The AOGS 2024 conference will be an opportunity to present the latest with the design and development of MIRMIS.