The Space Fence, or what is formally called the U.S. Air Force Space Situational Surveillance System (AFSSS), operational since 1961, is being shut down. AFSSS, consisting of three transmitters and six receivers placed across the southern U.S. and using radio waves, has kept a watch on what is going on in outer space. Many may consider outer space to be uninhabited and empty, but the reality is that over the decades it has been filled with millions of pieces of man-made junk that could cause huge harm to functioning assets. We need several systems to have a comprehensive coverage of the space environment. The United States has the largest network, even though its coverage of the Southern Hemisphere is not adequate. Russia has the second-largest network, followed by the European Union.

With the U.S. having shut down one of its major space situational awareness networks, major spacefaring powers need to make it a priority to contemplate possible solutions to track satellites and orbital debris on a continued basis.

The United States plans to set up a new Space Fence, which is to enter service in 2018. It has the potential to track much smaller objects than its predecessor and is also believed to be more accurate.

Until the replacement is ready, the duties of the AFSSS will be distributed to other branches; U.S. Air Force Space Command says it has “devised modified operating modes for the Perimeter Acquisition Radar Characterization System at Cavalier Air Force Station, N.D., and for the space surveillance radar at Eglin Air Force Base, Fla., which allows the discontinuation of AFSSS operations while still maintaining solid space situational awareness.”

However, the shutdown does highlight the increasing trend of budget cuts’ constraining the ability of nations to utilize their capabilities in such critical areas. The absence of such programs leaves all of us vulnerable. Given such trends, states have to think of international collaboration to get things going. How this should be worked out is something for all the major spacefaring states to consider.

Should there be a consortium of countries to keep the Space Fence up and running under an international agreement? In the face of divisive politics, it might be more appealing if such an arrangement were routed through a dedicated U.N.-affiliated agency for space traffic, like the International Civil Aviation Organization for air traffic.

Even as it sounds clichéd, outer space is becoming more crowded, congested and contested. With new players still emerging in the space domain, and newer and smaller satellites entering into service, the challenges of tracking are significant. Given the potential for damage that could be done if satellites or other objects sent into space collide with each other and the numerous challenges triggered by natural causes, there is a need to build a space monitoring mechanism. Due to the costs and technology involved in creating such a mechanism, international cooperation will be crucial.

So far there have been a total of nine accidents that involved accidental collisions in outer space. Out of these, the collision of the Russian Cosmos satellite with the U.S. Iridium 33 satellite was the only incident where two satellites directly collided. All other collisions involved debris from different activities in outer space. According to NASA’s Orbital Debris Program Office, “More than 21,000 orbital debris larger than 10 cm are known to exist. The estimated population of particles between 1 and 10 cm in diameter is approximately 500,000. The number of particles smaller than 1 cm exceeds 100 million.” These objects travel at a very high velocity and inflict significant damage on satellites if they collide. A Chinese anti-satellite test in 2007 created more than 3,000 pieces of space debris, further aggravating the problem. Space weather, caused by charged particles created by the sun and Earth’s magnetic field, also creates disturbing conditions for space objects. Given the dependence of military as well as civilian infrastructures on assets in outer space, these threats are likely to create enormous damage if they are able to disrupt the functioning of these assets. Therefore, maintaining a steady monitoring system such as the AFSSS is vital.

The concept of space situational awareness (SSA), which includes predicting collisions in orbit, detecting launches of new space objects, predicting re-entry of space objects into the atmosphere and detecting threats and attacks on spacecraft, is crucial in predicting and preventing such events. This can be done with the use of radars, optical telescopes, electronic signal sensors, infrared sensors and spacecraft that are in orbit between Earth and the sun.

With the shutdown of the old Space Fence program, Air Force Space Command said it would save about $14 million annually. However, the huge amount of data on space objects around the Earth made available through this program was significant. More importantly, as Brian Weeden of the Secure World Foundation writes, “The U.S. military also uses the data to offer a close approach warning service for owner-operators of the more than 1,000 active satellites in orbit.” Using this data, more than 10,000 warnings of potential collisions were issued, and 75 “avoidance maneuvers” were supported. This highlights the extent of vulnerabilities without a continuing tracking system.

Several established space powers, including India, have a range of technologies set in place to detect and trace objects in space. Russia has the second-largest network of radars and sensors, providing a catalog of space objects. As of now, Russia, through bilateral agreements, collaborates with some of the Central Asian countries where it has located its space surveillance systems. The Russian Space Surveillance System comprises mostly phased array radars and some dedicated radars and optical telescopes.

Europe has sufficient numbers of radars and networks to monitor space objects although they are not nearly as comprehensive as the U.S. or Russian systems. The European effort is also not a coordinated one at this instance given that it is run and operated by only a few countries, including the United Kingdom, France, Germany and Norway. In 2008, Europe initiated the SSA Preparatory Programme for creating a European Space Surveillance Network, and it has received support from a number of European countries. Most recently, in March, the European Commission, the executive arm of the European Union (EU), launched a new initiative to track and monitor space debris. While many European countries have national systems, radars or telescopes for tracking satellites and space debris, most of the European satellite operators have been relying on the U.S. space surveillance and tracking information. With this new initiative, the EU plans to combine all the different networks to track satellites and debris.

Another example of international cooperation in creating SSA is the International Scientific Optical Network — a collaboration between scientific and academic institutions with 20 observatories in 10 countries for tracking objects in space, instituted by the Russian Academy of Sciences in Moscow. The Space Data Association, a grouping of commercial entities,  also has a good network in this regard. It operates an automated SSA system that aims to reduce the risk of collisions and radio frequency interference. Its members currently include government and private satellite operators such as NASA, Avanti Communications, Arabsat and Telesat. The costs incurred are shared by participants and therefore reduce individual costs; this particularly could be useful given the tight budgets under which most agencies are operating.

India too possesses a wide array of ground-based tracking facilities. The Indian Space Research Organisation (ISRO) Tracking and Command Network of ground stations across India offers critical support for India’s space missions and operations. Additionally, the Indian Deep Space Network provides operational assistance to ISRO and other space agencies, and India’s two Swordfish tracking radars have the ability to track activities in space.

All of these cooperative arrangements increase security in space, but a global network for monitoring space would only contribute more toward this goal. It is beyond a single state’s capacity to monitor all activities that could threaten assets in outer space. This is why international cooperation will be crucial to prevent accidental collisions and to predict events such as the recent Chelyabinsk incident. There is a need for countries to come together and create a mechanism for sharing the information they collect about the space environment for improving security and minimizing threats in outer space.

There are several different issues in the shutdown of the Space Fence. SSA and space debris are important, but the larger and longer-term problem is space traffic control or management and safety of navigation in outer space. One could potentially look at strengthening the Space Fence in the first instance, but this has to grow into something bigger like an international space traffic management center. Such a center might come to work as a traffic controller for outer space and at a later stage could be tasked to move or remove space debris. But investment in technologies for removal of space debris is expensive. Given these realities, collaboration in technology development may be the only way to go. It may also be looked at as an incentive to secure greater support for an international code of conduct for space. Any technology developed under such a program should be freely available to all countries.

Rajeswari Pillai Rajagopalan is a Senior Fellow at the Observer Research Foundation in New Delhi. She served in India’s National Security Council Secretariat from 2003 to 2007. Rahul Prakash is a Junior Fellow at the Foundation.