sentences:  When the sampler horn attached to "Hayabusa2" underside touched the surface, a projectile (5-gram tantalum bullet) was fired at 300 m/s into the surface.The resulting ejecta particles were collected by a catcher at the top of the horn, which the ejecta reached under their own momentum under microgravity conditions.The sub-surface sample collection required an impactor to excavate a crater to eventually obtain material deeper from the sub-surface, which has not been subjected to space weathering.