The death rate for manned space missions is absurdly high. At the same time, robotics, AI, and remote control technology have all made incredible progress. Unmanned missions are much cheaper. So, an unmanned program is a greater bang for the buck, and a greater bang per death. See <a href="http://en.wikipedia.org/wiki/Space_accidents_and_incidents" rel="nofollow">http://en.wikipedia.org/wiki/Space_accidents_and_incidents</a>.<p>Let's say China sent people to Mars tomorrow. What could they learn about Mars that we couldn't learn by sending our robots there, similarly equipped? Manned space missions are now almost purely about bragging rights; the first person to do X in space was from nation Y. Who cares? It's just propaganda.