Mars, seen by Viking orbiter. (Courtesy NASA)

Over at Speaking of Science I have posted a few thoughts on Elon Musk and his plan to colonize Mars. Shorter version: Putting even one person on Mars, never mind a million people, is going to be very hard. There is no single technological show-stopper. But the risks are cumulative, the costs are incalculable, things go wrong, and any timeline that imagines humans on Mars in the next decade is magical thinking. Ask Loren Grush at The Verge: She runs through the whole list of challenges.

No one’s trying to dash anyone’s dreams here, but colonizing Mars isn’t simply a matter of rocket science. Musk and his colleagues have gotten good at rocket science (notwithstanding a couple of major failures in the past 15 months), but the biological part of a Mars mission is what’s so tricky: keeping people alive. We’re Earthlings. We are not adapted to Mars, much less interplanetary space. Technology can potentially solve a lot of problems, but we don’t even know what all the problems are.

Humans on Mars would be really cool. You could do a lot of great science. It would be a great adventure. The very process of trying to do it would surely have beneficial technological spin-offs. Musk and his fellow engineers are likely to make breakthroughs that will improve life here on Earth.

But Mars is not, for me, a satisfying Option B in case Earth becomes uninhabitable. A couple of years ago I wrote about the movie “Interstellar” and ended with some thoughts about terrestrial defeatism:

Among would-be star trekkers and planet-colonizers (Elon Musk et al) there’s often an implicit message that our goal as human beings ought to be survival on another world after our own is ruined. In “Interstellar” we see an O’Neill space colony where kids can play baseball but where, I’m guessing, the elephants didn’t make the cut, nor the whales, nor most of the other species from Earth. Really? That’s the best we can do? That’s the happy ending? If Earth dies and humans wind up somewhere else that’s not a W in my book, it’s a big L.

Further Reading: Why it’s so hard to get to Mars

NASA has a spaceship, but where will it go?