Tim Holden

Supplying fuel for a Mars expedition from the lunar surface is often suggested, but it's hard to make it pay off - Moon bases are expensive, and just buying more rockets to launch fuel from Earth is relatively cheap.

The best way to get a sense of what kinds of emergencies might present themselves in your community is by contacting local chapters of the American Red Cross or offices of emergency management in the region or state. Most large cities will have their own offices of emergency management.