Why NASA and ESA are trying to crash a spaceship into an asteroid

European and American space officials have launched plans to deflect asteroids away from the Earth, in hopes of better protecting the planet and of understanding the way asteroids form and operate.

Or, as Quartz puts it, “NASA and ESA are forming a super space team to prevent armageddon.”

The project, called the Asteroid Impact and Deflection Assessment (AIDA) Mission, was first announced in 2012. But it wasn’t until this year that officials declared a target for its studies: a near-Earth binary asteroid named 65803 Didymos.

This system, whose name is Greek for "twin," contains two asteroids: a small one (“Didymoon”) orbiting its larger counterpart (“Didymos”).

NASA's and the European Space Agency's schedules has been synchronized, but each mission is “fully independent,” ESA says on its website. “Therefore if for some reason one of the spacecraft cannot contribute to the joint campaign, the other would still be able to achieve its individual mission goals.”

ESA’s Asteroid Impact Mission (AIM) will launch first in October 2020. These will examine the structure of the asteroids and observe as NASA’s Double Asteroid Redirection Test (DART) spacecraft joins two years later.

Then comes DART’s crash – “straight into the asteroid moon [Didymoon] at about 6 km/s,” said ESA. “DART’s shifting of Didymoon’s orbit would mark the first time humanity has altered the dynamics of a Solar System body in a measurable way.”

What, one might ask, is the point of all this?

Perhaps the most poignant example comes from 2013 Chelyabinsk, Russia, when a meteor explosion described as “a tiny asteroid” tore through the city, injuring as many as 1,000 people. While such high numbers of casualties were unprecedented, “the risk of asteroid impacts ... may be 10 times greater than previously thought,” SPACE.com later reported.

“Our Earth is constantly bombarded by small asteroids that try to penetrate its protective atmosphere,” ESA explains. “The vast majority don't get through, but larger asteroids could pose a threat.”

The international mission hopes to “provide a baseline for planning any future planetary defense strategies,” the agency says, “offering insight into the kind of force needed to shift the orbit of any incoming asteroid, and better understand how the technique could be applied if a real threat were to occur.”