Space is an unnatural environment for humans. We can’t survive unprotected in a pure vacuum for more than two minutes. Getting to space involves being strapped to a barely contained chemical explosion. Since 1961, fewer than 700 people have been into space. Private space companies such as SpaceX and Blue Origin hope to boost that number to many thousands, and SpaceX is already taking bookings for flights to Earth orbit.

I’m an astronomer who has written extensively about space travel, including a book about our future off Earth. I think a lot about the risks and rewards of exploring space. As the commercial space industry takes off, there will be accidents and people will die. Polaris Dawn, carried out a high-risk mission in early September using only civilian astronauts, without incident. Still, now is a good time to assess the risks and rewards of leaving the Earth.

DANGERS OF SPACE TRAVEL

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