Small steps and giant leaps

As everyone must know by now, today is the 40th anniversary of Neil Armstrong and Buzz Aldrin walking on the Moon.  This is a natural occasion for people like Tom Wolfe and many others to think about the future of human space flight.  So here’s one astrophysicist’s opinion.

There’s one good reason to consider trying to send humans to Mars: It’d be awesome to send humans to Mars. The idea of people going to places people have never been before is incredibly exciting and inspiring.  If we do it, we should do it for its own intrinsic awesomeness.

Here are some bad reasons to send humans to Mars:

Bad reason 1. To do science.  Sending fragile human bodies to Mars (and then of course having to bring them back) is about the least cost-effective way imaginable to gain scientific data bout Mars.  Wolfe says

"Why not send robots?" is a common refrain. And once more it is the late Wernher von Braun who comes up with the rejoinder. One of the things he most enjoyed saying was that there is no computerized explorer in the world with more than a tiny fraction of the power of a chemical analog computer known as the human brain, which is easily reproduced by unskilled labor.

but, with all due respect to both Wolfe and von Braun, this is nonsense.  The point is that we don’t have to choose between sending robots and having human brains in charge: we can and do send robots that are controlled by humans on Earth.

Bad reason 2. To give us an alternative for when the Sun goes out.  Wolfe again:

It's been a long time, but I remember [von Braun] saying something like this: Here on Earth we live on a planet that is in orbit around the Sun. The Sun itself is a star that is on fire and will someday burn up, leaving our solar system uninhabitable. Therefore we must build a bridge to the stars, because as far as we know, we are the only sentient creatures in the entire universe. When do we start building that bridge to the stars? We begin as soon as we are able, and this is that time. We must not fail in this obligation we have to keep alive the only meaningful life we know of.

This sounds plausible at first, but the problem is that the time scales are all wrong.  This is a good argument for a policy that would ramp us up  interstellar travel on a time scale of a billion years or so, but it’s certainly not obvious that going to Mars now (on a time scale of 10 or 100 years) is the right strategy to reach that billion-year goal. On the contrary, we’re much more likely to reach that long-term goal by slowly developing as a species, improving our technology in a bunch of ways that we haven’t even thought of yet. It’s totally implausible that pouring a lot of resources into the specific narrow goal of sending a hunk of metal with a few humans in it to Mars is the most efficient way to further the needed slow, long-term development.

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Ted Bunn

I am chair of the physics department at the University of Richmond. In addition to teaching a variety of undergraduate physics courses, I work on a variety of research projects in cosmology, the study of the origin, structure, and evolution of the Universe. University of Richmond undergraduates are involved in all aspects of this research. If you want to know more about my research, ask me!

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