NASA thinks it can get people to Mars a little faster, said Tereza Pultarova at Space. A group of researchers at the University of Michigan, working with NASA, have developed a new ion-based thruster that could propel humans to the Red Planet "at much greater speeds than chemical-propulsion rockets can." The X3 thruster uses electricity, "usually generated by solar panels, to expel plasma — a gas-like cloud of charged particles — out a nozzle" to generate thrust. (Courtesy image) This technique helps rockets go faster: The maximum velocity that can be achieved by a chemical rocket is about 5 kilometers per second, whereas the X3 could get a craft up to 40 kilometers per second — while also using less propellant.