I'm retired astronaut Ed Lu, now running the B612 Foundation. We are a private organization at the forefront of protecting the Earth from asteroid impacts. AMA!
Asteroids hit the Earth more often than most people realize. The B612 Foundation is a nonprofit working to predict asteroid impacts decades ahead of time, so that we can use existing technology to prevent those impacts from happening. We've assembled the world's finest group of spacecraft engineers and mission designers to carry out the Sentinel Mission. I've been lucky enough to get to be part of some great projects, but the Sentinel Mission is the most important thing I've ever done.
added 11:12AM - thanks everyone - it's been fun!