Not just a robot on Mars - a nuclear-powered, laser-toting, semi-autonomous robot on Mars, relaying its data via one of the permanent space ships orbiting Mars to one of the many ground-based receivers hosted by different countries. It's a feat of science, engineering and human ingenuity that crosses geopolitical borders, which is why it's so important.

I feel a lot of the return on spacefaring is as simple as making groups of humans, a long way from each other, work together because of shared interests.