027 Satellite Flaring Paper

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All-domain Anomaly Resolution Office (AARO) 1 An AARO Information Paper Correlations of Starlink 1 Satellite Flaring with UAP Observations December 2024 Introduction With the advent of satellite communication mega-constellations including the SpaceX Starlink, Eutelsat OneWeb, Amazon Kuiper, and Chinese G60 constellations, there are currently thousands of artificial satellites in Low Earth Orbit (LEO) 2 and tens of thousands more planned for launch over the next decade [1]. Satellite

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NARA NAID 493468580 · RG 615

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All-domain Anomaly Resolution Office (AARO) 1 An AARO Information Paper Correlations of Starlink 1 Satellite Flaring with UAP Observations December 2024 Introduction With the advent of satellite communication mega-constellations including the SpaceX Starlink, Eutelsat OneWeb, Amazon Kuiper, and Chinese G60 constellations, there are currently thousands of artificial satellites in Low Earth Orbit (LEO) 2 and tens of thousands more planned for launch over the next decade [1]. Satellite flaring is an optical phenomenon which occurs when sunlight reflects off a satellite's surfaces, such as antennas or solar panels. This paper discusses specular and diffuse reflection of sunlight from man-made satellites and how these effects can be misinterpreted as unidentified anomalous phenomena (UAP). It also provides a method for observers to determine whether observations may be attributable to satellite flaring. Background Using reflected sunlight from man-made satellites to observe and track their movement goes back to the earliest days of space exploration [2]. As noted above, several companies develop and launch mega-constellations, providing internet access to most of the globe. Currently, there are nearly 10,000 artificial satellites in LEO and this number is expected to grow several-fold over the next decade [1]. Figure 1 illustrates the location of Starlink satellites in orbit as of December 2, 2024, at 11:00 AM Eastern Standard Time. As of the end of November 2024, there were over 6,700 Starlink satellites in orbit. Figure 2 illustrates the concepts of diffuse and specular reflections, which describe how light bounces off objects. Figure 3 shows how sunlight reflected in these two ways is directed toward an observer on the surface of the Earth. As seen in the left side of Figure 2, diffuse reflection occurs when light reflects from a rough or irregular surface. Light impinging upon a rough surface reflects in many directions, which spreads the light over a large range of angles from the reflecting surface, as illustrated by the gray colored "light cone” in the Figure 3(a). From a single observation point, this cone of light can be visible for up to several minutes as the satellite moves in its orbit across the sky. Additionally, the intensity of reflected light significantly decreases the further away the observer is from the reflecting surface. At the Earth’s surface, the intensity of diffusely reflected light from a satellite in LEO will typically have diminished to the point that the brightness is 1 Any reference to a non-federal entity is for informational purposes only and does not constitute an express or implied endorsement of any commercial service, from AARO, the Department of Defense, or the Executive Branch. This report focuses on Starlink satellites, but its principles are applicable for any analogous satellite constellation. 2 Altitude for Low Earth Orbit (LEO) ranges from 300km to 2,000km. 027 Page determined to be Unclassified Reviewed by Chief of Staff, AARO IAW FY24 NDAA, Section 1841(a)(1)(C) Date: 2/14/2025 All-Domain Anomaly Resolution Office Chief of Staff, AARO Authority: FY24 NDAA, now codified at 44 U.S.C. 2107 Date: 2/14/2025 Released in Full: X Case Number: 330UAP000027 All-domain Anomaly Resolution Office (AARO) 2 comparable to starlight. Due to their construction and orientation, many man-made satellites in LEO diffusely reflect sunlight and can appear as stars that move across the night sky. Figure 1: Graphic of Starlink satellites in orbit. Ref: https://www.heavens- above.com/StarLink.aspx Specular reflection, also known as glint, occurs from a very smooth, mirror-like surface as illustrated on the right side of Figure 2. Unlike diffusely reflected light, the light striking a smooth surface reflects light at the same, or nearly the same, angle as the incident light. Therefore, the reflected light cone from a satellite in LEO is much narrower for specular reflection as compared to diffuse reflection, as illustrated in Figure 3(b). This dramatically increases its observed brightness by several orders of magnitude, but greatly decreases its observation time as the cone passes over the observer. Figure 2: Image illustrating the difference between diffuse reflection (left) and specular reflection (right). 027 Page determined to be Unclassified Reviewed by Chief of Staff, AARO IAW FY24 NDAA, Section 1841(a)(1)(C) Date: 2/14/2025 All-domain Anomaly Resolution Office (AARO) 3 These very bright, short lived flashes of light are called “satellite flares” or “satellite glint.” The design, launch, and operation of SpaceX Starlink mega-constellations has led to a significant increase in the sighting of satellite flares, dubbed “Starlink flares,” noted by scientists and non- scientists alike. Figure 3: Illustration of (a) diffuse reflection of sunlight from a satellite and (b) specular refl…

Metadata

Agency
Department of Defense. Office of the Secretary of Defense. (09/18/1947 - )
Classification
UNCLASSIFIED
Department
Department of Defense. Office of the Secretary of Defense. (09/18/1947 - )
Confidence60
Credibility70

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NAID
493468580
File
027_Satellite_Flaring_Paper.pdf
Type
application/pdf

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027 Satellite Flaring Paper · UFOIntel