Turn Signals for Satellites


Drivers in my New England home state infamously and illegally change lanes without looking or signaling. Crashes ensue. They would feel right at home behind a flight console since satellite operators legally can and do maneuver without first alerting anyone or looking around. Almost a year since the release of the U.S. national space policy is a good time to get serious about collision avoidance before we face a multi-car pileup.

Admittedly, unlike cars satellites lack turn signals to alert others. Other operators aren’t looking, but are flying blind because their satellites are not equipped to spot hazards such as approaching satellites and space debris. Unlike ships, satellites are not subject to anti-collision regulations and no buoys mark safe navigation channels. Unlike airplanes, satellites need not file flight plans or operate under mandatory, Federal Aviation Administration-like ‘traffic control’ regimes.

Most operators actively track their own satellites and know accurately where they are (ephemeris) and where they intend to go (planned maneuvers). Yet they lack insight into plans of others and a road map. To get the basic idea — imagine that every satellite ‘car’ has blacked-out windows, travels at thousands of miles per hour with a blindfolded driver and there are no ‘road rules’ or traffic police. The driver has a GPS, but no map. Are you worried yet? Until the 2009 Iridium-Cosmos collision, a laissez-faire ‘big sky’ approach to satellite operations prevailed on the dubious assumption that space ‘roads’ were clean and free of traffic. President Barack Obama’s administration rejected this approach last year, issuing a policy recognizing the increasingly congested, contested and competitive nature of space and calling for government and commercial efforts to foster the development of space collision warning measures.

The U.S. Department of Defense, whose Joint Space Operations Center (JSpOC) provides limited collision warning services using its space surveillance network for certain operators, recently released its national security space strategy in concert with the intelligence community. While the JSpOC benefits from the finest space surveillance network available, it cannot continuously track every hazardous space object or read the minds of satellite operators to account for their planned maneuvers. Significant political and technical barriers suggest the JSpOC is unlikely to evolve anytime soon into a global ‘space traffic control’ center.

In any case, both governments and commercial operators will likely resist adoption of binding international ‘space traffic control’ measures and, judging by U.S. political reaction to the European Union’s October, 2010, nonbinding Code of Conduct for Outer Space Activities, any such measures remain decades away. More ominously, in May the U.S. Government Accountability Office noted that the Defense Department’s “critical” JSpOC Mission System (JMS) and Space Fence programs “face development challenges and risks.”

Meanwhile, non-U.S. governments are developing their own space surveillance capabilities with scant regard to building a global collision warning utility. Governments, alone, will not provide a comprehensive solution.

Fortunately, over the past year leading commercial satellite operators have developed, using advanced technology, a common sense approach to collision warnings. They have essentially equipped their satellites with virtual ‘turn signals’ and agreed to use them in advance to signal their maneuvers to others. Their solution allows them to build, maintain, and share an up-to-date map of known hazards to space navigation, including satellites and debris.

Remarkably, operator members of the Space Data Association have agreed as a legally binding condition of membership to transmit their measured locations and planned maneuvers for each of their satellites to the Space Data Center (SDC) before making any maneuvers. SDA membership is open to all commercial and government satellite operators and funded using a nominal annual membership fee to offset continuing operating costs. Many operators have already joined. Unlike the Department of Defense, the SDA doesn’t operate its own sensor network.

The SDC receives, validates, and converts contributed information into a common standard. The SDC automatically analyzes data and securely warns the affected operator(s) when a satellite’s course or a planned maneuver would bring a satellite too close to another satellite or known space debris. The satellite operator(s) can use the warning to adjust its planned maneuver and the SDC immediately reanalyzes the revised maneuver plans. Operators are always free to maneuver (or not) at will and access to and use of information contributed is protected by technical and legal means. The substantial nonrecurring investments required to bring the SDC into service have already been made and the SDC is operational today.

Some government satellite operators may not wish to signal where their satellites are or where they are going, citing security concerns. Thus, near-term prospects for building a single nongovernment database of satellite operations are poor. However, by working with SDA governments can benefit from its efforts to ensure that the highest quality information on satellite positions and maneuvers can be used — even for nonpublic operations.

Satellite collisions are not inevitable and new regulations are not required. Instead, operators should make the best use of available information. Isn’t it time government, commercial and civil satellite operators worked together to securely share their maneuver plans with each other? We may never be ready for mandatory space traffic control but perhaps the rest of the world’s satellite operators should join those in the Space Data Association who have responsibly decided to use their ‘turn signals’ before changing lanes.


Andrew D’Uva is a former international satellite communications executive and founder of Providence Access Co., a policy consultancy in Arlington, Virginia.