Orbital Debris and Governance
By Dr. Ray Williamson
After more than three decades of promising advances in satellite remote sensing that never quite gained market traction outside of defense applications, remote sensing has started to take off commercially. Over the last five years, several companies and at least a dozen additional governments have either launched remote sensing satellites into orbit or announced plans to do so this year. As the quality and quantity of available data have increased, so has the timeliness of delivery after acquisition.
The value-added sector, which focuses on making satellite and other remotely sensed data useful in commercial and governmental applications, has grown right along with the proliferation of satellite systems. Aided by the extensive use of GPS for location and GIS for display and analysis, value-added companies have brought the power of satellite remote sensing to a broad variety of customers.
Yes, the future looks brighter than ever for satellite remote sensing. Yet, in addition to the risks of launch or equipment failure in orbit, satellite data providers face one increasingly worrisome threat to space operations–orbital debris.
Debris left in space by launch and deployment procedures, or by unintended satellite breakup, has always posed a definite risk to working satellites. However, until the last decade the risk has been quite acceptable. As Theresa Hitchens writes in this issue on page 36, not only has the number of trackable debris objects generated by normal space operations grown to worrisome proportions, the Chinese test of an antisatellite (ASAT) weapon, which destroyed a Chinese polar-orbiting weather satellite, has added significantly to the debris cloud in sun-synchronous low Earth orbit (LEO). Those orbits include nearly all satellites with remote sensing payloads.
The concern is not so much for the potential of satellites being destroyed in some future conflict between nations, but in its encountering one of the many thousands of pieces of debris left behind by the test. Even small bits of debris like fasteners can cause great damage to spacecraft because the average impact velocities of debris with other space objects approaches 10 km/sec.
We value satellite systems because they provide the global perspective that aerial systems cannot. Not only can they cover wide areas in a synoptic view, they can observe any territory in the world regardless of national boundary. The legal basis of this capability comes about as a result of the 1967 Outer Space Treaty, which states in Article I, “Outer space... shall be free for exploration and use by all States without discrimination of any kind.” This provision is what makes satellite observations so valuable as reconnaissance tools. Unlike aircraft, satellites are not bound by the sovereignty laws of countries they overfly. This treaty also makes satellite images valuable for treaty verification, cross-border environmental monitoring, heritage conservation, and a host of other applications where national laws might impede the ability to gather information. In other words, satellite observations provide a level of global transparency not achievable by aircraft.
This year, the world celebrates its first 50 years in space; the Chinese test is a very poor way to celebrate this milestone. The 300 or so functioning satellites in LEO are at much greater risk of failure than prior to the test.
This is one of the last satellite images from the Chinese FY-1C, showing the eastern half of the U.S. The image was received by and is courtesy of the Center for Earth Observing and Space Research at George Mason University. Images processed by Dr. Guido Cervone, Jacek Radzikowski, and Dr. Menas Kafatos.
For more than a decade, space-faring nations, including China, have banded together in the Inter-Agency Space Debris Coordination Committee (IADC) to find ways to reduce the production of debris in space, which is a natural consequence of space activities. Yet, this single test has added some 1500 pieces 10 cm and greater in size, to the 11,000 or so already in space. I find the decision to perform this test both puzzling and sad.
U.S. officials have tended to respond to the test by renewing calls for increased U.S. investment in countermeasures and in a revived U.S. ASAT development effort. Both the United States and the Soviet Union tested ASAT weapons in the 1970s and '80s, also leaving long-lived debris in orbit. However, both countries soon reckoned that their space funds would be better spent elsewhere. In my view that was the right decision. Space systems have become too important to world commerce and peacekeeping to risk further pollution of space by space debris.
Despite the problems the Chinese test has created for satellites in orbit, perhaps something good can come out of the test in the form of an increased awareness of the threat to space systems from orbital debris and the need to reduce that threat. In fact, in my view, the Chinese test generally increases the incentive to craft and adopt internationally acceptable “rules of the road” for space, with the goals of not only reducing the threat of damage from orbital debris, but also assisting all countries in establishing and maintaining relatively safe access to space.
Countries of the world long ago banded together to establish rules of the road for international civil air traffic, governed by the International Civil Aviation Organization (ICAO). It is not too far-fetched an idea to believe that space-faring nations could reach agreement on some basic rules of space traffic control and pollution avoidance to govern activities in outer space–in other words, to move toward a regime of orbital governance.
Ray A. Williamson is research professor of space policy and international affairs in the Space Policy Institute of The George Washington University (Washington, D.C.) and co-editor, with John C. Baker and Kevin O’Connell, of Commercial Observation Satellites: At the Leading Edge of Global Transparency (Rand and ASPRS, 2001).