Author: Joseph Hall

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.