tinitro ~rates ~enate 
WASHINGTON, DC 20510 
The Honorable Ajit Pai 
Chairman 
Federal Communications Commission 
445 12th Street, SW 
Washington, DC 20554 
Dear Chairman Pai, 
September 29, 2017 
We are writing to express our concern for the growing challenge presented by low-Emth orbit 
(LEO) space debris. As the Commission considers multiple requests for new LEO satellite 
constellations, we ask that you formally coordinate with the National Aeronautics and Space 
Administration (NASA) and the Federal Aviation Administration (FAA) to establish an 
interagency working group on space debris and to develop a comprehensive domestic policy on 
space debris mitigation. 
We note that NASA, as stated in its own filings with the Commission, is conducting an internal 
parametric study on large constellations, which will be completed later this year. As part of your 
coordination with NASA on this issue, we ask that the Commission use any recommendations or 
best practices from this study to info1m regulatory decisions on LEO constellation permitting. 
As you may know, the U.S. Department of Defense Space Surveillance Network currently tracks 
nearly 22,000 pieces of orbital debris, defined as man-made objects in Earth' s orbit that no 
longer serve a useful purpose. This figure does not include hundreds of thousands of pieces of 
debris smaller than 1 Ocm that are also orbiting the Earth. Collisions with debris as small as I Ocm 
can catastrophically damage satellites, and debris as small as lcm can disable spacecraft. Each 
collision exponentially increases the likelihood of another collision, creating a potential cascade 
that could severely inhibit future telecommunications, national security, and other space-based 
activity in the LEO environment. 
In the last decade, two major satellite collisions dramatically increased the amount of fragmented 
debris cull'ently in orbit. Model predictions suggest that even with nearly full compliance with 
existing mitigation measures, LEO space debris is expected to grow by an average of 30% in the 
next 200 years. A number of national and international studies have concluded that orbital debris 
may have already reached a tipping point. 
Collectively, if approved, the applications pending at the Commission for new satellite 
constellations could drastically increase the number of satellites in LEO. In light of these 
pending requests, we remind you of the United States' obligation to ensure that any licensed 
system will not operate near other systems in a way that could potentially create space new 
debris, endanger national and international assets, and threaten our future access to space. 
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We are extremely excited by the unique potential for these proposed satellite constellations to 
connect rural and underserved American populations to the internet. However, swift action to 
mitigate the collision risk associated with a growing number of constellations is critical to 
ensuring the long-term sustainability of our space environment. 
We stand ready and willing to support the Commission, NASA and FAA in establishing 
comprehensive regulatory policy to mitigate the space debris challenge. We appreciate your 
prompt attention to this issue and we look forward to discussing further. 
Sincerely, 
~~~ 
Dan Sullivan 
United States Senator 
cc: The Honorable Robert M. Lightfoot, Jr. 
Acting Administrator, National Aeronautics and Space Administration 
The Honorable Michael P. Huerta 
Administrator, Federal Aviation Administration