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We Need a Better Bullet-Bucket

Of all the doomsday scenarios in existence, one is simultaneously the most likely to happen and paid such little attention. It is also, in my opinion, the most depressing.

I'm talking about the militarization of low earth-orbit (LEO). In "Star Wars Forever? -- A Cosmic Perspective" the husband-wife duo of Joel Primack and Nancy Abrams from the Physics Department at UC Santa Cruz, describe a frighteningly simple and realistic vision of our future:

Abstract: [...] The current debate over missile defense has failed to emphasize a crucial point: even one war in space will create a battlefield that will last forever, encasing the entire planet in a shell of whizzing debris that will thereafter make space near the earth highly hazardous for peaceful as well as military purposes. With enough orbiting debris, pieces will begin to hit other pieces, whose fragments will in turn hit more pieces, setting off a chain reaction of destruction that will leave a lethal halo around the Earth. No actual space war even has to be fought to create this catastrophe; any country that felt threatened by America's starting to place lasers or other weapons into space would only have to launch the equivalent of gravel to destroy the sophisticated weaponry. Wise people have pointed out that missile defense will waste hundreds of billions of dollars that could be spent combating the real threats in the modern world. Short term political interests pale before the overwhelming, eternal immorality of imprisoning Earth for all future generations in a halo of bullets. This horrible crime would dishonor our ancestors, plant and animal alike, who bequeathed this beautiful blue planet to us, and cripple our descendents, who would never forgive us.

This is a profoundly simple and scary point: It is very hard if not impossible to "clean up" most Earth orbits. Regardless of how they become cluttered, certain orbits are resilient to atmospheric drag and space debris will remain there for millennia unless we either endeavor to keep it clean or find a nifty way of cleaning it up.

So, what can we do? Cleaning up space debris should be easy, right? Wrong. Imagine trying to collect bullets with a bucket; not easy.

What about not fielding weapons--like kinetic energy interceptors or explosive missiles--that cause explosions in LEO? That is a step in the right direction, but still not enough. Primack and Abrams point out that even other types of weapons such as directed energy weapons can still start the chain reaction, "Any country that felt threatened by America's starting to place lasers or other weapons into space would only have to launch the equivalent of gravel to destroy the sophisticated weaponry." This would start a chain reaction with at first only a few orbits being unusable. Inevitably, this debris would create more debris through collisions at orbital velocities.

There is only one real solution: We need to be very conservative about deployment of weapons in LEO.

What are the consequences if we do not do this? First, substantial real estate in LEO will be unusable and it would be very hard to deliver space hardware to orbits near debris-filled orbits. Services such as GPS, telecom, radar, and earth observation as well as scientific research would all be drastically affected if not shut down entirely until someone built a better bullet-bucket.

Second, the human race would be largely robbed of any hope of establishing manned scientific outposts on the moon and mars. It would be risky, sure, to attempt to deploy space hardware through a cloud of extremely fast-moving bullets, however any crew and human-rated hardware would face orders of magnitude more risk.

It is truly ironic that some of the most popular doomsday scenarios concentrate on the destruction of the human race (nuclear war, disease, nanotech's "grey goo", etc.) when, in fact, we are much closer to imprisoning the people of Earth for millennia in a cloak of impenetrable space debris.