  Asteroids are frequently colliding with small projectiles. Although each
individual small collision is not very important, their cumulative effect can
substantially change topography and also the overall shape of an asteroid. We
run simulations of random collisions onto a single target asteroid represented
by triaxial ellipsoid. We investigated asteroids of several hundred meters to
about 18 km in diameter for which we assumed all material excavated by the
collision to escape the asteroid. The cumulative effect of these collisions is
an increasing elongation of the asteroid figure. However, the estimated
timescale of this process is much longer than the collisional lifetime of
asteroids. Therefore, we conclude that small collisions are probably not
responsible for the overall shape of small asteroids.
