NASA’s Asteroid Defense Mission Enters Next Phase

Artist's rendering of the Double Asteroid Redirection Test (DART) spacecraft. (Image courtesy of NASA.)

Sixty-six million years ago, the planet was radically transformed by the impact of an asteroid. Most megafauna on the Earth perished, plants stopped photosynthesizing and the sky was choked by dust. It was an apocalypse.

Since that time, no other impact events of the same caliber have occurred on Earth, but they could, and that’s why NASA is pursuing the Double Asteroid Redirection Test (DART) program.

As currently imagined, the DART mission would see a refrigerator-sized spacecraft target a binary asteroid system named Didymos with hopes of demolishing one of the two space rocks. Although the Didymos pair are tied together, the two objects are staggeringly different in size. The larger rock, Didymos A, is about a half-mile in size while its companion, Didymos B, is a paltry 530 feet across.

Obviously, NASA will be targeting the smaller of the two satellites.

According to NASA, sometime between 2022 and 2024, the DART mission will autonomously guide itself toward Didymos B. Travelling nine times faster than the speed of a bullet at 3.7 miles per second, the mission’s craft will crash into the asteroid, but not obliterate it.

Instead, the impact should jostle the rock into a different path relative to Didymos A. Using ground-based observations, NASA scientist will look to see if the kinetic energy imparted by DART on the Didymos system was sufficient to nudge it off its current course. If it is, then researchers will have a proof of concept mission that shows how Earth might be protected from potentially deadly asteroids by directed impactors.

“DART is a critical step in demonstrating we can protect our planet from a future asteroid impact,” said Andy Cheng of the Johns Hopkins Applied Physics Laboratory and DART program co-lead. “Since we don’t know that much about their internal structure or composition, we need to perform this experiment on a real asteroid. With DART, we can show how to protect Earth from an asteroid strike with a kinetic impactor”.

DART is still in the design phase of the mission, but moving the program from concept development to a more material phase means we might actually be taking steps to protect the long term future of life on this planet.

Oh, and by the way, the Didymos pair is considered a potentially hazardous asteroid, but don't worry: it’ll be a while before it has a chance to splash down on Earth.

For more planetary defense news, find out how a team of engineers is Using Drones to Combat Asteroids.