In 2019, NASA will send out a robotic probe to retrieve an asteroid. And it’ll be this little piece of futuristic engineering that helps it get the job done. Later, we go to Mars.
It’s called a xenon-ion propulsion engine, and instead of using rocket fuel, it harnesses magnetic fields to create thrust. If you take a look at the image above, you can see a tiny blue jet of the thruster. The stunning blue glow comes from photons released by the ions as they lose energy upon leaving the engine.