Mission to...?

Mr. Obama wants an astronaut or two to land on one of these things in the interest of science and exploration.  Also to see if man could nudge one of these things just in case.

Just in case of what?

After the past 10 years, I'm not sure our government just comes out and says anything straight up.  No offense. Something we don't know about? See this trailer from 1951...sad part is I remember it.