3. Foster commercialization

There is no agreement among scientists over the role private enterprise ought to play in human spaceflight. Yet already, commercial companies help build the machines that carry astronauts into space.

Many experts think space tourism and even certain mining and manufacturing will succeed in space if only entrepreneurs are turned loose (and perhaps assisted with federal money or incentives).

"Perhaps future space probes will be plastered in commercial logos, just as Formula I racers are now," Rees says. "Perhaps 'robo-wars' in space will be a lucrative spectator sport."

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