Actually, there are very good reasons to stop spending billions of dollars on manned space missions, to explore space in ways that are safer and much less costly, and to grant much higher priority to other scientific and engineering mega-projects, the oceans in particular.

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The main costs of space exploration arise from the fact that we are set on sending humans, rather than robots. The reasons such efforts drive up the costs include: A human needs a return ticket, while a robot can go one way. Space vehicles for humans must be made safe, while we can risk a bunch of robots without losing sleep. Robots are much easier to feed, experience little trouble when subject to prolonged weightlessness, and are much easier to shield from radiation. And they can do most tasks humans can.