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.
The prototype, which was recently inspected by NASA chief Charles Bolden, sits in a vacuum chamber where it’s being tested at NASA’s Jet Propulsion Laboratory in Pasadena, California.
Also called a solar-electric ion propulsion engine or Hall effect thruster, it’s powered by an inert and odorless xenon gas. The engine works by combining high energy, negatively charged electrons together with neutral propellant atoms (the xenon gas) in a contained environment. Within all this excitement, mini-collisions produce a second electron — which creates the thrust.
Since the ions are generated in a region of high positive and the accelerator grid's potential is negative, the ions are attracted toward the accelerator grid and are focused out of the discharge chamber through the apertures, creating thousands of ion jets. The stream of all the ion jets together is called the ion beam. The thrust force is the force that exists between the upstream ions and the accelerator grid. The exhaust velocity of the ions in the beam is based on the voltage applied to the optics.
Ion engines will be fuel-efficient and more suited for space travel. And indeed, NASA plans to launch an ion-powered unmanned spacecraft to capture a small asteroid and re-locate it in the moon’s neighborhood. Afterwards, a spacewalking team will get to it via the Orion space capsule currently under development. NASA hopes to retrieve the asteroid in 2019 and explore it in 2021.
This is all in preparation of larger, more important missions, including a trip to Mars. In addition, ion engines could be used to power spacecraft capable of redirecting incoming asteroids.