NASA’s first ever planetary defense test mission is set to launch Tuesday night. It's an attempt to deflect an asteroid 6.5 million miles from earth.
Scientists who worked on dart – or “Double Asteroid Redirection Test” will launch a spacecraft aimed to collide with the target asteroid, “Dimorphos”.
Millions of miles from earth, Dimorphos orbits around the larger asteroid “Didymos” - hence the ‘double asteroid’ in the dart acronym.
The planned collision won't shift the asteroid dramatically. Thomas Zurbuchen, head of science at NASA, explains the reasoning, "Our hope is to prove that by impacting a spacecraft onto the rock, we change its movement, we change its overall speed."
Changing the orbit speed would also alter the orbit path around the larger asteroid. The anticipated change would be small but in this case, a little goes a long way to keeping Earth safe from any future threat.
We won't see the actual result of this for some time - the launch window opens early Wednesday morning and scheduled impact isn’t until next fall.