Space is getting messy. The debris in Earth's orbit keeps multiplying, damaging satellites and putting astronauts in harm's way. If the problem gets severe enough, it could eventually make low-Earth orbit unusable.
Scientists have known about the space trash problem since the 1970s. Humans have placed thousands of objects into orbit since Sputnik, and some of those old satellites and ejected rockets are breaking apart. As pieces collide with each other at high speeds and shatter, they create more debris. Repeat until space is saturated with high-flying junk.
Yet despite ample warning, the world's nations have never quite been able to agree how to solve the problem. The technology to clean up debris exists, but no one can decide how to pay for it. So that's where economists come in.
In a recent paper, three economists argue that orbital debris is a standard "tragedy of the commons" problem. Space is a resource, and people overuse it, since no one pays the price for creating waste. No one entity has enough incentive to clean up the mess alone. Economists typically solve this problem with what's known as a Pigouvian tax. Why not place a user fee on all orbital launches to pay for cleanup?
"User fees are a solution straight out of the Reagan era to deal with these environmental issues," says Peter J. Alexander, an economist at the Federal Communications Commission and a coauthor of the paper.
The orbits around Earth are undeniably valuable. Satellites are used for everything from communications to television to Earth monitoring and military surveillance. Roughly 49 percent of satellites are in low-Earth orbit, which is also where astronauts work. Another 41 percent are higher up, in geosynchronous orbit.
Yet those orbits are getting clogged. The U.S. Strategic Command is aware of more than 21,000 man-made objects in orbit larger than 10 centimeters, but there are hundreds of thousands of even smaller pieces circling the Earth that can't be tracked. Some of them are moving as fast as 22,000 miles per hour.
Satellites periodically have to adjust their orbits to steer clear of passing debris. Astronauts working on the International Space Station occasionally have to scramble into their Soyuz escape capsule when metal shards fly near.
The nightmare scenario is a cascade of collisions that becomes unstoppable. Metal shards would start destroying satellites, which would create even more debris, until low-Earth orbit became unusable. This is known as the "Kessler syndrome," named after NASA astrophysicist Donald Kessler who first predicted the possibility in 1978.
So far, a chain reaction hasn't occurred, and Kessler's initial prediction of an apocalypse by 2000 turned out to be premature. But there are warning signs. Back in 2009, we saw the first major collision between two intact satellites — a U.S. Iridium and an aging Russian Cosmos. The end result: 2,000 additional chunks of metal flying around Earth.
Here's the good news: Scientists have come up with clever schemes to mop up the orbital debris. We may be able to shove the really troublesome chunks into "graveyard orbit," 22,000 miles away from the Earth. Recently, aerospace engineers at the University of Colorado outlined a plan to haul away space debris using static electricity.
The problem is that the world's nations can't agree on how to pay for these cleanup efforts. Everyone has an incentive to keep launching satellites into space. No one has any incentive to invest in cleaning up the debris left behind.
So, in their paper, the economists propose a simple solution: Countries should impose a basic fee or tax on all orbital launches. The fee would have to be set high enough so that companies and nations don't overpopulate space with objects. And the revenues could fund cleanup missions.
Still, a user fee would create its own set of headaches. How does the tax get divvied up? Most of the debris currently in space, after all, was put there by the United States and Russia, with China a close third. (In 2007, China blew up one of its own satellites to show off its weapons capabilities, creating an additional 3,000 bits of debris.) Should a launch tax apply retroactively? Should the United States and Russia pay most of it?
"Those are good questions," says Alexander. "The bargaining environment here has become incredibly complex. So we looked at the simplest solution, which was to impose a launch fee on a forward-going basis."
But even if an international fee wouldn't be easy to negotiate, the authors say, it's also clear that the current system is failing. "If you look at what NASA's saying, even in the absence of new launches, the amount of debris will continue to grow over the next 200 years," says Alexander.