Researchers from the Australian National University have created a prototype thruster that could offer a new form of propulsion for spacecraft. The thruster is called the Helicon Double Layer Thruster (HDLT), and it works by passing hydrogen atoms through a magnetic field to create a beam of plasma. Like an ion engine, it's electrically powered and very efficient - solar arrays could provide the energy to power the thruster. Other agencies, including NASA, are working on plasma thrusters, but this is the first to be proven to work with hydrogen.