I am Mason Peck, NASA's Chief Technologist. Ask me anything about our asteroid initiative.
When I was here about a month ago, I mentioned that you should keep watching for ways to engage with NASA on asteroids and Redditor 21p99c asked for an AMA on the subject. So: here it is. In addition to NASA’s mission to find, capture and redirect, and then send humans to explore a near Earth asteroid, we need to find all asteroid threats to human populations and know what to do about them. Yes, we’re going to save the world (and no, we’re not doing it Bruce Willis style). Ask me anything about NASA’s asteroid plans and how you can help.
Update: Thanks everyone for another great set of questions. If my schedule allows, I'll come back and answer a few more questions. Tune in to the latest for what we're doing with asteroids at http://www.nasa.gov/asteroidinitiative and I hope you'll be a part of our effort.
Update: Dropped in this morning to answer a few more questions. Also to let you know that if you have ideas for NASA's asteroid initiative, you can send them to us by responding to the Request for Information. More about that here: http://www.nasa.gov/mission_pages/asteroids/initiative/asteroid-rfi.html