The surface of the Moon is constantly exposed to the solar wind-a stream of charged particles from the Sun that can dislodge atoms from the lunar surface and contribute to its thin exosphere. However, a new study by Vienna University of Technology (TU Wien) and international collaborators reveals that earlier models greatly overestimated this sputtering effect.
The researchers attribute th by Robert Schreiber
Berlin, Germany (SPX) Jul 24, 2025
The surface of the Moon is constantly exposed to the solar wind-a stream of charged particles from the Sun that can dislodge atoms from the lunar surface and contribute to its thin exosphere. However, a new study by Vienna University of Technology (TU Wien) and international collaborators reveals that earlier models greatly overestimated this sputtering effect.
The researchers attribute the discrepancy to simplified assumptions about the Moon's surface. Past calculations assumed a smooth, dense surface, ignoring the rough, porous texture of actual lunar regolith. By combining precision experiments with advanced simulations, the team has now established more accurate sputtering rates.
TU Wien scientists used authentic lunar samples from NASA's Apollo 16 mission and a custom-built quartz crystal microbalance to measure minute mass losses during ion bombardment. Simultaneously, large-scale 3D simulations run on the Vienna Scientific Cluster incorporated real-world surface geometry and porosity into the modeling.
The findings show that solar wind-induced erosion is up to ten times lower than previously thought. The porous structure of lunar regolith causes many of the high-energy ions to dissipate their energy before ejecting atoms, sharply reducing the sputtering yield.
"Our study provides the first realistic, experimentally validated sputtering yields for actual lunar rock," said Prof. Friedrich Aumayr. "This helps explain why prior models overstated the solar wind's role and independently supports a recent isotope-based study suggesting that micrometeorites-not solar wind-are the primary drivers of the lunar exosphere."
The results hold important implications beyond lunar science. With NASA's Artemis program targeting renewed Moon exploration and ESA-JAXA's BepiColombo mission aiming to study Mercury's exosphere, understanding true surface erosion dynamics is critical for interpreting future observational data.
Research Report:Solar wind erosion of lunar regolith is suppressed by surface morphology and regolith properties
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