IEEE Spectrum reports that a NASA engineer has come up with a new way to fling satellites through space on mere grams of fuel, tens of times as efficiently as today’s best space probe thrusters. Instead of using deuterium and tritium as the fuel stocks, the new motor extracts energy from boron fuel. Using boron, an “aneutronic” fuel, yields several advantages over conventional nuclear fusion. The idea is a long way from becoming a practical device, however.