Mercury observed in thermal infrared for the first time

Mercury observed in thermal infrared for the first time
by Robert Schreiber
Berlin, Germany (SPX) Dec 13, 2024

Mercury, the smallest and innermost planet in the solar system, continues to intrigue planetary researchers with its unique composition and structure, which differ significantly from Earth's Moon despite surface similarities. BepiColombo, a collaborative mission by the European Space Agency (ESA) and Japan Aerospace Exploration Agency (JAXA), aims to resolve these mysteries. Launched in 2018, the spacecraft is set to enter Mercury's orbit in November 2026.

On December 1, 2024, during its fifth flyby at an altitude of 37,630 kilometers, BepiColombo's MERTIS (Mercury Radiometer and Thermal Infrared Spectrometer) instrument captured unprecedented thermal infrared data from Mercury's surface. This marks the first time Mercury has been studied in wavelengths between 7 and 14 micrometers, enabling detailed analysis of the planet's thermal radiation. Temperatures measured during the flyby reached up to 420 degrees Celsius, providing critical insights into Mercury's mineralogy and surface properties.

Jorn Helbert of the DLR Institute of Planetary Research, Co-Principal Investigator for MERTIS, expressed enthusiasm for the milestone. "After about two decades of development, laboratory measurements, and mission preparation, the first data from the space probe is now available. It is simply fantastic!"

Harald Hiesinger, a planetary geologist at the University of Munster leading the MERTIS team, emphasized the importance of this data. "We are seeing Mercury in a completely new light thanks to MERTIS. We are breaking new ground and will be much better able to understand the composition, mineralogy, and temperatures on Mercury."

MERTIS, developed by DLR with contributions from German industry, is a lightweight and efficient instrument weighing just three kilograms. Project manager Gisbert Peter highlighted its reliability and the significance of the data collected, noting, "After a six-year cruise to Mercury, the instrument is operating very reliably and delivering impressive measurements."

This latest flyby also allowed MERTIS to observe notable geological features such as the Caloris impact basin and the Basho impact crater. MERTIS data confirmed the unique characteristics of Basho, which exhibits strikingly bright and dark materials. These observations pave the way for future analyses that will deepen understanding of Mercury's surface composition.

BepiColombo's complex journey to Mercury involves close cooperation between European and Japanese teams. The mission's components include the Mercury Transfer Module (MTM) for propulsion, the Mercury Planetary Orbiter (MPO) for scientific investigations, and the Mercury Magnetospheric Orbiter (MMO) contributed by JAXA.

While MERTIS has already provided groundbreaking data from its flybys, the instrument's full capabilities will be realized once BepiColombo enters Mercury's orbit. At that stage, the instrument will deliver data with resolutions as high as 500 meters, further illuminating the planet's geology and thermal environment.

The BepiColombo mission exemplifies international collaboration, with contributions from multiple European institutions and the United States. German involvement, spearheaded by DLR and supported by federal funding, played a pivotal role in the mission's development.