For its crazy 2020 asteroid capture mission and other projects, NASA is developing next-gen "Hall effect thrusters" to corral an asteroid and put it into the moon's orbit. At the same time, the European Space Agency (ESA) is trying to improve its own Hall thrusters to power future missions. If you're wondering what the heck they are, Hall effect motors are a type of ion thruster that produce a tiny 0.7 pounds of force, or the weight of 54 US quarters, according to NASA. However, they're much more efficient than standard rockets, and if run long enough, can power a spaceship to speeds as high as 112,000 mph. So how do they actually work?