Space dust kills satellites like tiny atom bombs

HOW is a speck of dust like an atom bomb? It sounds like a child’s riddle. But the answer may explain the fate of many satellites that have failed prematurely in orbit over the years. For the riddle to work, the speck must be travelling at 70km a second, or thereabouts. If it is, the riddle’s solution is that both can generate an electromagnetic pulse capable of knocking out unprotected electronic equipment.

That, at least, is the hypothesis now being investigated by Sigrid Close of Stanford University. Dr Close came up with it in 2010, when she was shooting small particles at various types of spacecraft material placed inside a vacuum chamber at the Max Planck Institute in Heidelberg, Germany. These experiments suggested that when a micrometeoroid, to give such dust its technical name, collides with a satellite, it will not just do a small amount of mechanical damage. If travelling fast enough, it will also create a shock wave that vaporises part of the spacecraft’s metallic skin.