  Spin off events and impacts can eject boulders from an asteroid surface and
rubble pile asteroids can accumulate from debris following a collision between
large asteroids. These processes produce a population of gravitational bound
objects in orbit that can impact an asteroid surface at low velocity and with a
distribution of impact angles. We present laboratory experiments of low
velocity spherical projectiles into a fine granular medium, sand. We delineate
velocity and impact angles giving ricochets, those giving projectiles that
roll-out from the impact crater and those that stop within their impact crater.
With high speed camera images and fluorescent markers on the projectiles we
track spin and projectile trajectories during impact. We find that the
projectile only reaches a rolling without slipping condition well after the
marble has reached peak penetration depth. The required friction coefficient
during the penetration phase of impact is 4-5 times lower than that of the sand
suggesting that the sand is fluidized near the projectile surface during
penetration. We find that the critical grazing impact critical angle dividing
ricochets from roll-outs, increases with increasing impact velocity. The
critical angles for ricochet and for roll-out as a function of velocity can be
matched by an empirical model during the rebound phase that balances a lift
force against gravity. We estimate constraints on projectile radius, velocity
and impact angle that would allow projectiles on asteroids to ricochet or roll
away from impact, finally coming to rest distant from their initial impact
sites.
