I'd think that a planetary protection officer would have a much larger portfolio than just worrying about extraterrestrial biological contamination. If he's not responsible for detecting and fending off errant asteroids and comets, who is?

"If he's not responsible for detecting and fending off errant asteroids and comets, who is?"

Well, we're responsible for worrying about it. I wonder if the detection couldn't be handled in a distributed fashion?

I saw a telescope at Wal-Mart a few weeks ago that featured a computer hookup and remote control. A few thousand of those spotted across the planet, sweeping the sky for incoming, stashing the results in a central database via the internet ... remote control of the telescope via batch command "sweep between x and y coordinates for such and such hours".

Fending off incoming would have to be a matter for the state, of course.

the problem with spotting asteroids from earth is that the ones we're worried about spend most of their time sunward of the earth, so they're difficult to spot. what we need is one or more sensors (telescopes) looking across the space between sun and earth. spacecraft at L1 (between sun and earth) or L4/L5 (in same orbit as earth but 60 degrees behind or ahead of earth) would have excellent vantage points for looking for near-earth asteroids.