2. Bring nations together

Just as the International Space Station packed explorers from previously antagonistic nations into tight quarters, an effort to return to the Moon could bring nations together in an era of increasing international tension, some analysts say.

China, with its own lunar ambitions, is a good example of a country the United States might want to work more closely with.

"I think the international public would cheer a program designed as a flagship for how space technology can be a role model for letting technicians of various countries work together in programs that would benefit all of us," said William K. Hartmann, a senior scientist at the Planetary Science Institute in Tucson.

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