The situation that asteroid hunters both train for and dread is the discovery of a large space rock on a collision course with planet Earth. Recently we got a chance to practice on a small harmless space rock named 2020 XK1 that eventually zipped past us. About once a month a small space rock like 2020 XK1 enters the Earth's atmosphere, creates a super fireball meteor, bursts into a cloud of fragments at 135,000 feet, and rains fragments of itself onto the ground for meteorite hunters to discover.