For a few years now, ion propulsion technology's sci-fi mechanics have raised the standard for flying spacecraft, replacing fiery rocket tails as the new in-thing. Ion propulsion can be about 10 times faster than normal fuel and can continuously run for prolonged periods of time, gaining a wicked amount of speed along the way. One drawback, however, is it's typically employed with xenon thrusters. JAXA's Hayabusa2 mission used the classic xenon as a fuel. Xenon, a heavy noble gas, is exceptionally rare on Earth, pricey and difficult to maintain. That's why French aerospace company ThrustMe is pursuing a plan for...