The Chinese explored the Middle East and Africa almost 100 years before the Europeans. Every expedition consisted of 300 ships, some as long as 400 feet with 9 mast and an armada crew totaling 28,000 men. After 30 years of doing it they realized that they were spending too much money on these grand expeditions. The succeeding emperor ended the program. The Europeans on the other hand would send out just a few ships and try to find ways for the expeditions to be profitable (Slaves, gold, land, colonies) in ways the Chinese never thought. These smaller European expeditions could not be stopped by one emperor because Europe was not a unified empire like China. The smaller European kingdoms also competed against each other. This not only made the expeditions sustainable but thrive for the next 500 years. Right now I think we are in China's situation 600 years ago. We stopped the moon landings for the same reason the Chinese stopped landing Eunuchs in Africa. Unless we find a way for these space programs to be profitable I don't see humans colonizing space anytime soon.