Bill Gates

Governments will always play a huge part in solving big problems. They set public policy and are uniquely able to provide the resources to make sure solutions reach everyone who needs them. They also fund basic research, which is a crucial component of the innovation that improves life for everyone.

Having a Congress with a more diverse educational and professional background would serve the country well. And given the budget challenges facing America today, we might benefit from a few more cold, calculating problem solvers, and fewer courtroom impresarios.

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.