Integrating Space Traffic into the National Airspace System

Story and photos by Victoria A. Brown
Reprinted with permission from FAA Aviation News

Picture a world where spacecraft and aircraft share the same airspace from take-off to re-entry to landing, and where airplanes do not have to be grounded because spacecraft need to use the airspace. In this world, air traffic controllers will control air and space traffic together. Soon you no longer have to daydream what it would be like, because a system that can help to make this all possible is now being developed.

With the anticipated increase in air traffic and spacecraft operations, the Federal Aviation Administration (FAA) expects greater demands on the National Airspace System (NAS) and the nation's Air Traffic Control (ATC) system over the next 10 years. To handle this influx in traffic, the FAA has developed a concept of operations for a future Space and Air Traffic Management System (SATMS). SATMS represents a framework for "seamlessly integrating" space vehicles on their way to and from space with more traditional air traffic operations. Of course, this will entail new space and air traffic management tools along with improved communications, navigation, and surveillance services.

There are unique hazards involving space flights. If a space vehicle should fail in a manner that generates debris, as occurred with the space shuttle Columbia accident, it could pose a grave threat to aircraft flying below. A piece of spacecraft debris weighing less than one pound could puncture the wing or cabin of a cruising aircraft causing catastrophic damage. Since potential hazards from spacecraft operations pose far greater risks than any other aircraft hazard traditionally considered, SATMS would need to address these issues to make the NAS even safer than it is today.

Currently, there are several strategies used to manage air traffic. The Notice to Airmen (NOTAMs) method alerts the aviation community, including air traffic controllers, airlines, and general aviation pilots of the times of space flight operations and boundaries of the required airspace. The airspace restrictions are enforced by Title 14 Code of Federal Regulations (14 CFR) part 91. Special Use Airspace (SUA) establishes Restricted Areas and Warning Areas. Restricted Areas are established with fixed boundaries and are illegal to enter without permission from the controlling agency. Altitudes and times of activation differ. Warning Areas are airspace over domestic or international waters that extend from three nautical miles outward from the coast of the United States. Warning Areas are advisory in nature to alert pilots that they may be entering areas of hazardous activity to nonparticipating pilots. Lastly, air traffic controllers have the option to issue a Temporary Flight Restriction (TFR). This is a short-term restriction to keep aircraft from entering certain areas. TFRs are often issued on very short notice for a variety of reasons. The airspace is sized for the largest vehicles that may use it with fixed boundaries and are typically activated for extended periods of time. These methods also impact space vehicle operators because they require extensive advanced coordination with various ATC entities, and it is sometimes difficult to accommodate launch delays and scrubs.

In the future, FAA hopes to reduce the amount of airspace that is restricted for each launch and the amount of time that the restriction needs to be in effect. FAA also hopes to schedule the restrictions to accommodate conventional air traffic while still achieving the safety and space mission objectives. One of the ways FAA plans to achieve this is through space transition corridors. A space transition corridor is a strategically sized airspace restriction. Its vertical extent spans all altitudes and the lateral sizing will be determined by using specific characteristics of vehicle operations and predicted weather conditions. It will be dynamically issued and withdrawn to minimize impact to air traffic.

In the case of an accident, the SATMS Decision Support Tool (SATMS DST) will ultimately assist air traffic controllers in managing airspace and the risk to aircraft from space operations with improved situational awareness. Air traffic controllers will be able to better predict airspace affected by debris. This tool will also identify and plan the most efficient air traffic reroutes as well as track the spacecraft, or in the worse case scenario, its debris through the NAS.

Needless to say, there is a lot of planning and analyzing that goes into developing this system. Before the space shuttle Columbia accident, FAA air traffic procedures for supporting space shuttle operations did not take into consideration the potential debris hazard to aircraft during a shuttle reentry. For this reason, the Shuttle Recovery Ops Team was formed. The team consists of participants from the National Aeronautics and Space Administration's (NASA) Johnson Space Center and FAA's Office of Commercial Space Transportation, Air Traffic Control System Command Center, William J. Hughes Technical Center, Albuquerque Air Route Traffic Control Center (ARTCC), Houston ARTCC, Jacksonville ARTCC, Los Angeles ARTCC, Miami ARTCC, and Oakland ARTCC. Until the SATMS DST is fully developed and functional, the Shuttle Recovery Ops Team runs shuttle reentry exercises to train and prepare air traffic controllers for possible accidents like Columbia. These exercises simulate what could happen in the event of a space shuttle accident. On the last re-entry exercise the "shuttle debris" entered over Los Angeles ARTCC's airspace. In the exercise, Oakland and Albuquerque ARTCCs assisted Los Angeles in moving potentially at risk aircraft away from harm. After the exercise was completed, all parties agreed that this training was indeed beneficial.

The SATMS Decision Support Tool would automate the processes involved. Ultimately the goal is for the SATMS DST to compile all the information from any given accident or launch and re-entry vehicle operation and translate that data into a real-time tool that ATC would use to manage the traffic situation.

FAA is working with NASA to ensure that the skies stay as safe as possible during space launches. Furthermore, both organizations are practicing to become as proficient as possible. With the expected air traffic increase and the development of commercial space flights, SATMS DST provides an important means to manage the expected workload.

Victoria Brown was an FAA summer intern. She is a communications major at Xavier University in Cincinnati, Ohio.