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Didymos, a 2,650-foot-wide asteroid, has an atypical cosmic companion— a 535 foot-wide satellite named Didymoon (10). These new two celestial bodies are not making a dangerous rendezvous with Earth, but they do provide an interesting opportunity for an apocalyptic dress rehearsal.

NASA and ESA’s Double Asteroid Redirection Test (DART) will head to Didymos, to knock Didymoon off course. Along with its six picture-snapping Italian Space Agency cubesats, the mission will also send a follow-up ESA spacecraft named Hera to definitively answer if we can manipulate the trajectory of Earth-bound asteroids.

But to pull this off, the DART mission is going to need some serious horsepower to get it to the Didymos system, which lies 6.8 million miles from Earth. Fortunately, NASA’s Evolutionary Xenon Thruster—Commercial ion engine, or NEXT-C for short, will get it there.

NEXT-C, which is made up of a thruster and a power-processing unit, was designed by researchers at NASA’s Glenn Research Center and by Aerojet Rocketdyne in Redmond, Washington.

“Serving as the primary propulsion source for DART, NEXT-C will establish a precedent for future use of electric propulsion to enable ambitious future science missions,” CEO and President of Aerojet Rocketdyne Eileen Drake said in a 2018 statement.“Electric propulsion reduces overall mission cost without sacrificing reliability or mission success.”

Unlike your typical rocket, ion drives like those in NEXT-C and NASA’s NSTAR, which powered DAWN and Deep Space 1, use solar power to accelerate a propellant. First, solar panels capture light energy and convert it to electricity which provides a positive charge to the first of two grids. This zap sends the propellant—in the case of NEXT-C, that’s xenon ions—to the second, negatively charged accelerator grid and then out of the engines as thrust.

NEXT-C is currently undergoing a series of environmental and performance tests, Universe Today reports. The thruster, which generates up to 6.9 kW of thrust power and 236 mN thrust, has already undergone the required spaceflight tests, including thermal vacuum and vibration.

DART is scheduled to launch in July, 2021

Excerpted from https://www.popularmechanics.com/space/a31944498/nasa-dart-mission-engine/