Shields for Icarus Part1: The Impact Hazard

Space is really, really BIG and immense speeds are necessary for space vehicles to cross the gulfs between the stars within a reasonable time-frame. At such high speeds (in the case of “Icarus” somewhere between 30,000 to 60,000 km/s) a collision with a sand-grain massing just a milligram would release 450 megajoules of kinetic energy, which is equivalent to about 100 kilograms of TNT. Such a collision hazard seems insuperable if we focus on the kinetic energy of sand grains, but just how many are out there? More specifically just how many collisions does a space-vehicle need protection from during a typical mission? (more…)