In rarefied atmospheric environments, where continuum fluid dynamics breaks down, aerodynamic drag is governed by gas-surface momentum exchange, making surface structure and chemistry key design knobs. Using molecular dynamics simulations, we show that coating the α-Al2O3(0001) surface with graphene markedly reduces the tangential momentum accommodation coefficient (TMAC) of N2, shifting scattering toward more specular reflection and thereby lowering drag; we further benchmark this response against graphite. The reduction strengthens up to 900 K. While structural defects can increase TMAC via defect-induced corrugation and local atomic and electronic rearrangements, graphene retains its performance at experimentally relevant defect densities.
@article{arxiv.2602.00285,
title = {Defects, Corrugation and Temperature Govern Rarefied-Air Drag on Graphene Coatings},
author = {Samuel Cajahuaringa and Davide Bidoggia and Maria Peressi and Antimo Marrazzo},
journal= {arXiv preprint arXiv:2602.00285},
year = {2026}
}