Near-Earth objects (NEOs) such as asteroids threaten the Earth because they have the potential to collide with it  The goal of NEO research is to develop measures to counteract a possible hit by a sizable NEO  Government funding of this research is not a waste of money
Buying home insurance makes good fiscal sense, and governments fund NEO research for the same reason that people insure their homes
It connects an analogy made in the argument to the argument's conclusion.