Characterize Mercury’s tens-of-meters-scale surface roughness

Characterize Mercury’s surface roughness at baselines of several tens of meters, which remains uncertain because existing Mercury digital terrain models lack sufficient spatial resolution.

Background

Existing Mercury digital terrain models restrict roughness calculations to baselines no shorter than approximately 65 m because their spatial resolution is limited. The paper therefore uses a high-resolution lunar digital terrain model and synthesized fractal topographies as analogs for Mercury in its laser-pulse simulations.

The authors find that these analog models span the roughness range observed in available Mercury terrain models, but explicitly note that roughness at baselines of several tens of meters is not yet known for Mercury. This unresolved characterization is relevant to BepiColombo Laser Altimeter observations, which may provide footprint-scale roughness information through digitized return-pulse shapes.

References

Although roughness at baselines of several tens of meters remains uncertain for Mercury, the range of roughness variations in the Apollo-17 DTM is likely comparable to those associated with specific geomorphological features on Mercury.

— Prospects for Mercury Observations with the BepiColombo Laser Altimeter (BELA): Implications for Estimating Surface Roughness from Laser Altimetry  (2609.20365 - Nishiyama et al., 17 Sep 2026) in Section 2.2, “Roughness Comparison among Analog DTMs”