Disentangle Starlink antenna reflections from attitude effects

Determine whether the large flat phased-array antennas on Starlink satellites, rather than satellite attitude effects, are responsible for the observed concentration of bright specular glints and the brighter upper envelope in the diffuse-scattering regime.

Background

The survey identifies a strong concentration of Starlink observations near the specular-scattering phase angle of approximately 115 degrees, together with a brighter upper envelope in the diffuse-scattering regime. The authors propose that the large flat phased-array antennas are a plausible physical cause because such surfaces can generate strong specular reflections.

However, the observations do not allow the contribution of satellite attitude effects to be separated from the contribution of antenna geometry. Resolving this attribution is important for mitigation: surface darkening would primarily reduce diffuse scattering, whereas suppressing specular reflections may require managing or redesigning large flat surfaces.

References

The strong Starlink concentration in the specular scattering peak near $115{\circ}$, together with its brighter upper envelope in the diffuse regime, implies that the Starlink design is inherently more prone to bright specular glints than the average LEO object. The large flat phased-array antennas are the plausible cause (though we cannot separate that from attitude effects observationally), and if so then mitigation must go beyond darkening surfaces (which acts mainly on the diffuse component) and must also manage large flat surfaces so as to suppress the specular one.

— Systematic non-compliance of satellite megaconstellations with IAU brightness limits  (2610.10834 - Rayworth et al., 7 Oct 2026) in Discussion section, paragraph beginning “The phase angle behaviour found in our survey points to a physical cause of these results.”