In some ways, the last place you’d want to put the James Webb Space Telescope is, well, in space. If you owned a $10 billion car, you wouldn’t leave it out in a hail storm, and while there’s no hail in space, there are plenty of micrometeoroids—high speed debris no bigger than a dust grain but moving so fast they can pack a true destructive wallop. Every day, millions of such fragments rain down on Earth, but they incinerate in the atmosphere long before they reach the ground. The Webb, parked in a spot in space 1.6 million km (1...