Prospects for Mercury Observations with the BepiColombo Laser Altimeter (BELA): Implications for Estimating Surface Roughness from Laser Altimetry
Abstract
Surface reflectance and roughness are key to understanding Mercury's geologic evolution. The BepiColombo Laser Altimeter (BELA) will measure these properties alongside topography, but predicting its performance requires realistic modeling of laser return pulse shapes, unlike a simplified Gaussian approximation in earlier models. We develop a comprehensive return-pulse simulation framework for BELA that includes non-Gaussian transmitted pulses, analog filtering in the receiver chain, and pulse-shape modification by footprint-scale topography. Using high-resolution lunar digital terrain models and synthesized fractal topography as Mercury analogs, we develop calibration and correction methods and estimate measurement errors expected in future BELA observations. Range errors average 1.5 m or less below 1000 km altitude, and energy errors are small enough to distinguish dark deposits, regolith, and exposed ice below 900 km. Pulse width proves unreliable as a roughness proxy under realistic conditions; we instead constrain roughness from digitized pulse shapes, underscoring the value of time-resolved data for future planetary altimeters.
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BibTeX
@misc{nishiyama2026prospects,
title = {{Prospects for Mercury Observations with the BepiColombo Laser Altimeter (BELA): Implications for Estimating Surface Roughness from Laser Altimetry}},
author = {Gaku Nishiyama and Alexander Stark and Christian Hüttig and Kai Wickhusen and Christian Althaus and Thomas Behnke and Ernst Hauber and Klaus Gwinner and Konrad Willner and Noriyuki Namiki and Frederic Schmidt and Jean Barron and Hugo Lancery and Azar Arghavanian and Hauke Hussmann},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.20365},
eprint = {2609.20365},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.20365},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Prospects for Mercury Observations with the BepiColombo Laser Altimeter (BELA): Implications for Estimating Surface Roughness from Laser Altimetry
AU - Gaku Nishiyama
AU - Alexander Stark
AU - Christian Hüttig
AU - Kai Wickhusen
AU - Christian Althaus
AU - Thomas Behnke
AU - Ernst Hauber
AU - Klaus Gwinner
AU - Konrad Willner
AU - Noriyuki Namiki
AU - Frederic Schmidt
AU - Jean Barron
AU - Hugo Lancery
AU - Azar Arghavanian
AU - Hauke Hussmann
PY - 2026
DA - 2026/09/17
PB - arXiv
DO - 10.48550/arxiv.2609.20365
UR - https://arxiv.org/abs/2609.20365
AB - Surface reflectance and roughness are key to understanding Mercury's geologic evolution. The BepiColombo Laser Altimeter (BELA) will measure these properties alongside topography, but predicting its performance requires realistic modeling of laser return pulse shapes, unlike a simplified Gaussian approximation in earlier models. We develop a comprehensive return-pulse simulation framework for BELA that includes non-Gaussian transmitted pulses, analog filtering in the receiver chain, and pulse-shape modification by footprint-scale topography. Using high-resolution lunar digital terrain models and synthesized fractal topography as Mercury analogs, we develop calibration and correction methods and estimate measurement errors expected in future BELA observations. Range errors average 1.5 m or less below 1000 km altitude, and energy errors are small enough to distinguish dark deposits, regolith, and exposed ice below 900 km. Pulse width proves unreliable as a roughness proxy under realistic conditions; we instead constrain roughness from digitized pulse shapes, underscoring the value of time-resolved data for future planetary altimeters.
ER -