Hm... my impression was that the Japanese had only invested a couple-hundred million in this area, primarily in IThEMS. AFAIK no entity on earth has ever put "tens of billions" on this. If you have info indicating otherwise, please cite.
As for the Chinese, it appears I got a few details wrong. They have spent $300M thus far, with plans to maintain this level of funding for the next few decades. You'll find a decent description of their program here. (But one thing I do know, which is not mentioned in the article: the project is led by a guy named Jiang Mianheng, who happens to be the son of Jiang Zemin, the former president. So I would guess their funding is pretty secure.)
Anyway, thanks for prompting me to look into it and get my facts straight.