small logo Guest Editorial

Cosmic Rays? No Problem!
by Allen Tough (tough77 @

In last month's Guest Editorial, Prof. Mario Zadnik introduced the idea that cosmic rays may fatally damage interstellar probes. Actually, we probably need not worry much about this. Here are some reasons for not worrying:

  1. No one else seems worried. In all the NASA material and web sites on interstellar travel that I have checked out, nothing is said about cosmic rays. Nor in the nanotechnology literature, as far as I can recall. Nor in the National Space Society position paper. Nor in any of the other 35 references in my "Small Smart Interstellar Probes" paper (preprint at

  2. We have to remember that any civilization we are likely to detect is probably thousands of years ahead of our technology. Even now, our nanotechnology literature indicates that within a few decades we will be able to manufacture "active materials" atom-by-atom. These intelligent active materials will incorporate sensors, diagnosis, and repair capacities right in the material itself. So any cosmic ray damage could presumably be repaired. (Nanotechnology, like interstellar probes, has become widely accepted within mainstream science over the past 2 years.)

  3. We need not worry about a probe surviving for "a few million years" as Zadnik mentions. A few thousand years might be enough if the probe travels only a few hundred lightyears.

  4. If our satellites and space station and interplanetary probes had been devastated by cosmic rays, I would worry more. You are right, they have been in existence only a fraction of the time needed for interstellar travel, but still they are the best practical test so far of likely damage from cosmic rays.

All in all, as we think about a civilization thousands of years ahead of our technology, it seems unlikely that cosmic rays will stop their interstellar exploration.

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