The European Space Agency (ESA) and Japan Aerospace Exploration Agency (JAXA) joint mission, BepiColombo, has revealed new insights into the surface of Mercury. On December 1, 2024, the spacecraft flew past the planet for the fifth time, becoming the first to observe it in mid-infrared light. The images captured by the German-led Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS) show variations in temperature and composition across the cratered surface.
Mercury is the least-explored rocky planet in the Solar System, with BepiColombo being the third mission to visit it. The spacecraft will enter orbit around Mercury in 2026, marking a significant milestone in its eight-year journey. During its flyby, MERTIS captured images of the Caloris Basin and a large volcanic plain in the northern hemisphere, shedding light on the planet’s mysterious surface.
The instrument’s unique ability to image Mercury in mid-infrared wavelengths has provided new information on the composition and temperature of the surface. The brightness of the surface depends on temperature, surface roughness, and mineral composition, with MERTIS sensitive to a specific range of infrared light. This data is crucial for interpreting how different minerals glow in mid-infrared light, which varies with temperature.
The BepiColombo team has been testing various materials and mineral mixtures in the lab, heating them to different temperatures to measure their glow in mid-infrared wavelengths. The findings will help understand why Mercury’s surface appears dark and poor in iron, a crucial element for the planet’s formation.
In preparation for its arrival at Mercury in 2026, MERTIS has undergone clever reprogramming of its software, allowing it to generate data during flybys without the instrument’s ‘planet port’ blocked. This innovation has proven successful during previous missions, enabling the team to test and calibrate the data produced by MERTIS.
The BepiColombo mission is a significant step forward in understanding Mercury’s surface and its composition. With both orbiters set to start science operations in early 2027, the spacecraft will gather valuable data for years to come, providing insights into this enigmatic planet.
Source: https://www.esa.int/Science_Exploration/Space_Science/BepiColombo/BepiColombo_reveals_Mercury_in_a_new_light