  It has been recently recognized that the surface of sub-km asteroids in
contact with the space environment is not fine-grained regolith but consists of
centimeter to meter-scale rocks. Here we aim to understand how the rocky
morphology of minor bodies react to the well known space erosion agents on the
Moon. We deploy a neural network and map a total of ~130,000 fragmented
boulders scattered across the lunar surface and visually identify a dozen
different desintegration morphologies corresponding to different failure modes.
We find that several fragmented boulder morphologies are equivalent to
morphologies observed on asteroid Bennu, suggesting that these morphologies on
the Moon and on asteroids are likely not diagnostic of their formation
mechanism. Our findings suggest that the boulder fragmentation process is
characterized by an internal weakening period with limited morphological signs
of damage at rock scale until a sudden highly efficient impact shattering event
occurs. In addition, we identify new morphologies such as breccia boulders with
an advection-like erosion style. We publicly release the produced fractured
boulder catalog along with this paper.
