Over 100 participants from 18 countries – including NASA scientists and the agency’s NEOWISE mission – took part in the international exercise. Watching the skies for large asteroids that could pose a hazard to the Earth is a global endeavor. So, to test their operational readiness, the international planetary defense community will sometimes use a real asteroid’s close approach as a mock encounter with a “new” potentially hazardous asteroid. The lessons learned could limit, or even prevent, global devastation should the scenario play out for real in the future. To that end, more than 100 astronomers from around the world...