FRITZ LODGE
Space can seem far away, but over the past 50 years it has become an integral part of modern life. Roughly 1,200 satellites in orbit link global telecommunications networks, provide real-time positioning to our phones, and monitor the Earth for climate events and natural disasters. Space assets are also a critical enabler for the U.S. military. According to former Secretary of the Air Force and Cipher Brief expert Deborah Lee James, “we depend upon space very heavily for missile warning… and all types of navigation and precision targeting.”
However, the rapid expansion of space use has also created a problem that could threaten the ability of all countries to effectively utilize Earth’s orbit. That problem is space debris. Currently, the United Sates and international agencies track almost 23,000 objects of uncontrolled space trash. Yet this is just a fraction of the estimated 750,000 pieces of smaller untracked debris, which still pose a significant threat to both unmanned satellites and the human crew of the International Space Station.
As SpaceX proposes an ambitious “mega-constellation” made up of over 4,000 new satellites to beam internet connection from low Earth orbit to billions around the globe; collisions, excess launch debris, and even space-based military operations like the Chinese kinetic anti-satellite weapons test in 2007 continue to spew new debris into orbit. If left unaddressed, this space junk could make parts of Earth’s orbit partially or even completely unusable.
At the moment, the only practical solution to space debris is tracking and avoiding uncontrolled objects. With enough warning, controlled satellites and the space station can maneuver to avoid large pieces of debris with relative ease, although dodging space trash does expend fuel. However, the real problem with this approach is that current tracking systems are unable to see anything below ten centimeters in size. According to Michael Simpson, Director of the Secure World Foundation, these objects “go down to perhaps a centimeter in size. That is about the size of a .22 caliber bullet moving 17,500 miles an hour, you can imagine the amount of damage that could cause.”
Plans are underway fill this gap in tracking and surveillance. The DARPA Space Surveillance Telescope – now transferred to the Air Force – improved space debris tracking when it came online in 2011 by allowing observers to monitor 10,000 objectsat a time, rather than viewing a few large objects through a narrow window. But Beijing’s intentional destruction of the Chinese Fengyun-1C weather satellite in 2007, which spewed out roughly 150,000 small pieces of untrackable debris, and the collision between the Iridium 33 and the Russian Cosmos 2251 satellites in 2009, which produced approximately 200,000 pieces, convinced the Air Force to begin work on a new second-generation tracking system in 2009. The Space Fence, set to be located in Western Australia, will use shorter wavelength S-band radar to detect much smaller particles in orbit, allowing the Air Force to track some 200,000 pieces of space debris, rather than the current 20,000.
However, improved surveillance and avoidance maneuvers are only one part of the solution. Catching and actually deorbiting uncontrolled objects in orbit, says Simpson, is the real “holy grail of space debris.” There are several programs around the world attempting to reach that goal. For instance, the Japanese Aerospace Exploration Agency (JAXA) has proposed an experimental program, which would clean up junk with a nearly half mile-long electrodynamic tether. Similarly, the RemoveDEBRIS program out of the University in Surrey is scheduled to launch a vehicle this year, which will test nets, harpoons, and other active debris removal techniques.
But all these projects are technologically complex – an early test of the JAXA system this February ended in failure – and they will require both large amounts of funding and sincere international cooperation. As Johann-Dietrich Woerner, Director-General of the European Space Agency (ESA), observes, “funding is difficult…[and] we are still pretty far away from true global cooperation on this.”
To some, another problem with actively cleaning trash from orbit is that the technologies used to deorbit a defunct satellite could also be used by certain countries to deorbit the military and intelligence satellites of their adversaries. This argument, says Woerner, is ridiculous, primarily because there is no need for a highly complex robot to knock enemy satellites out of orbit. That can be accomplished with a dumb kill vehicle. “Space debris,” he says, “does not know national borders. It does not know the nationality of any satellite… it endangers everyone equally. Therefore, this is a global challenge to be tackled together.”
Instead, the continued existence of significant space debris is more likely to spark conflict than the hypothetical threat posed by deorbiting technology, primarily because it can be very difficult to tell whether a fatal satellite collision was caused by debris or an intentional attack. It is not far-fetched to imagine a scenario in which the destruction of an American, Russian, or Chinese military satellite is misread as an attack and sparks escalatory space conflict.
Even without this kind of military escalation, space debris poses an increasingly apparent threat to global space use, especially at crowded low Earth orbits. Guidelines from the Interagency Space Debris Coordination Committee – an international inter-governmental cooperation body – have reduced the amount of debris that new launches produce, but near-Earth space is still littered with large derelict space assets that, if hit, could produce new clouds of debris.
This is the basis of the Kessler Syndrome, a phenomenon theorized by NASA scientist Donald Kessler, in which the destruction of large space assets creates clouds of debris that subsequently strike new satellites in an exponentially cascading event. The derelict 8,211 kilogram ESA Envisat satellite is often discussed as a possible trigger for this kind of Kessler cascade, which is why Director-General Woerner plans to propose a mission to remove it – the e.Deorbit program – at ESA’s next ministerial meeting.
This kind of nightmare scenario still seems relatively far off, but as the drastic reduction in commercial space launch costs continues, more and more assets are crowding the critical infrastructure of Earth’s orbits. Debris, if left unchecked, threatens to severely diminish the use of space, which could threaten the stability of the global economy and severely limit the ability of the U.S. military to operate around the globe. “In an apocalyptic scenario,” says Simpson, “it may even become nearly impossible to use space.”
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