Cleaning Up the Final Frontier
If the world needed a reminder of the sheer amount of stuff swirling around the planet, it received a spectacular one in mid-November. The European Space Agency’s 1.2-ton GOCE satellite, which had studied the earth’s gravitational field, ran out of fuel in low orbit, reentered the earth’s atmosphere, burned up into a fiery mess, and dumped debris across the southern Atlantic just south of the Falkland Islands. The Inter-Agency Space Debris Coordination Committee—a global space agency consortium that tracks “space junk”—activated surveillance facilities around the world to monitor the destruction of the bird.
Since the Soviets kicked off the Space Age by launching Sputnik 1 in 1957, mankind has sent more than 7,100 spacecraft of some sort aloft. Along the way, an expanding miasma of refuse—malfunctioning satellites, rocket motor effluents, metal fragments, equipment lost on space walks, and even tiny flecks of paint—has spread in orbit. Computer simulations by NASA portray what looks like a cloud of fruit flies swarming around an apple—only these fruit flies travel at 17,000 miles per hour. And at that speed even a particle can do serious damage to satellites or spacecraft—a scenario dramatized in Alfonso Cuarón’s sci-fi thriller Gravity.
The space refuse problem is most troublesome in low orbits of about 500 miles above the earth’s surface. There are 21,000 pieces of wreckage the size of grapefruit or bigger—and that number grows to 500,000 if you include fragments the size of BB pellets and dust specks, according to NASA data. Some of this detritus is burned off during reentry to earth. But depending on the trajectory, other pieces can stay in orbit for decades, even centuries. Former astronaut Michael Bloomfield remembers watching debris burning up in the atmosphere below him during one U.S. shuttle mission. “That gets your attention,” he says. So did the time a fragment slammed into the window, leaving a pit mark.
Even so, engineers disagree about how urgent the risk really is—and whether governments should spend billions on solutions that are years away from being ready. That’s practical, but maybe not the noblest way to look at the problem. The expense must be weighed against some kind of moral pressure to leave at least the final frontier unwrecked, if only to prove we can. That said, removing the refuse may be even more complicated than getting all that junk up there in the first place. Engineering hurdles aside, there’s no international consensus or legal framework to organize and pay for a multidecade cleanup effort.
You might call it the tragedy of the space commons, a 21st century twist on American ecologist Garrett Hardin’s theory, advanced in the late 1960s, that shared resources like grazing lands and fishing zones can be depleted by individuals, acting independently and rationally, to the greater detriment of a larger group.
Coming to an international agreement about global warming has been tough enough. It’s hard to imagine a power like Russia or China signing off on a plan by U.S. or European space agencies to operate the kind of orbiting trash collectors backed by some scientists and companies interested in government contracts. “The really hard part is trying to convince other countries that your garbage truck in space will be used for the peaceful purposes stated—and not to mess with other people’s satellites,” says Dave Baiocchi, an engineering professor at the Pardee RAND Graduate School.
There are three broad and evolving strategies to cope with space debris. One solution starts at blastoff: There’s been progress by commercial companies and space agencies to adopt smarter launch and design standards (limiting the use of explosive bolts, for example, normally used to separate rocket stages) to reduce the amount of space debris entering low earth orbits.
Governments are also investing in systems that can locate the junk. Raytheon and Lockheed Martin are in the hunt for a multibillion-dollar U.S. Air Force contract expected to be announced later this year that will fund a massive radar system to track stuff. Known as the space fence, it will be based in the Pacific or Australia and promises to give the U.S. the ability to identify more and smaller pieces of space debris with much greater accuracy than current systems.
In November the U.S. and Australia signed an agreement to move an advanced Space Surveillance Telescope developed by the Defense Advanced Research Projects Agency from its current mountaintop position in New Mexico to Australia to better find debris in the higher geosynchronous orbits about 22,000 miles above the earth’s surface.
Other more far-out ideas include the creation of solar-powered space nets and sails to collect and redirect space junk. In 2018 the Swiss Space Center at École Polytechnique Fédérale de Lausanne hopes to launch a cleanup craft from atop an Airbus A300, then use a robotic claw to retrieve an old satellite. Avoiding debris is also getting more sophisticated. Inventor Robert Hoyt, who runs a small company called Tethers Unlimited in Bothell, Wash., has pitched the idea of attaching a miles-long conducting wire to a spacecraft to drag against the earth’s magnetic field and move the vehicle out of harm’s way. He’s also created devices that could be attached to satellites and, operated from the ground, pop out and adjust a space vehicle’s orbit to avoid collisions. “A hundred years from now, low earth orbit may be nearly unusable,” says Hoyt. “Unless we go up and do active debris removal, then it is going to get out of hand.”
The amount of detritus has expanded exponentially since 2007, when the Chinese intentionally destroyed one of their weather satellites. Two years later came the accidental collision of the Iridium Communications SV33 and Russian Cosmos 2251 communications satellites over Siberia. The rubble generated from those two events now accounts for one-third of all cataloged orbital rubble, according to NASA data.
Even worse, debris crashing into debris is creating even more debris, a cascading effect that began by at least 2005, says J.-C. Liou, a scientist with NASA’s Orbital Debris Program Office. He estimates that five large pieces of wreckage will have to be removed every year starting in 2020 just to keep the overall amount of space debris level. “I believe that we have crossed the threshold into instability,” he says, predicting a crash like the Iridium incident once every five to 10 years.
Sounds grim, unless you factor in variables like the volume of space and the specific orbit in question, says William Welser IV, a professor at Pardee RAND and director of the Engineering and Applied Science Department, who co-authored the book Confronting Space Debris with his colleague Baiocchi. Not all orbits have the same junk density. Not all space assets require expensive space sails to protect them. “We actually think the risk of space debris in aggregate is overstated,” says Welser. “You have to look at this from a risk tolerance point of view.”
Things certainly look risky from the vantage point of Matthew Desch, who as chief executive officer of Iridium oversees a network of 66 communication satellites in the crowded low earth orbit. He lost the Iridium SV33, of course, but he also says the company has had to maneuver its satellites hundreds of times to dodge space jetsam. He likens the issue to another slow-moving and fiercely debated environmental challenge whose full costs may only be apparent decades from now. “Sounds a little bit like global warming, doesn’t it?” Desch says. “The reason why there is debris is because there is no cost to debris.”