Detection of Thermal Emission at Millimeter Wavelengths from Low-Earth Orbit Satellites

TL;DR

This paper reports the first detection of artificial satellite thermal emission at millimeter wavelengths using the SPT-3G, demonstrating high signal-to-noise detection and discussing implications for cosmological surveys and satellite tracking accuracy.

Contribution

It introduces the first observation of satellite thermal emission at millimeter wavelengths and presents an algorithm for satellite tracking based on orbital data and observatory constraints.

Findings

Thermal emission from satellites detectable at millimeter wavelengths with high SNR.

Satellite emissions do not significantly affect the SPT-3G survey maps.

Measured satellite positions often differ from TLE data by several arcminutes.

Abstract

The detection of artificial satellite thermal emission at millimeter wavelengths is presented using data from the 3rd-Generation receiver on the South Pole Telescope (SPT-3G). This represents the first reported detection of thermal emission from artificial satellites at millimeter wavelengths. Satellite thermal emission is shown to be detectable at high signal-to-noise ratios on timescales as short as a few tens of milliseconds. An algorithm for downloading orbital information and tracking known satellites given observer constraints and time-ordered observatory pointing is described. Consequences for cosmological surveys and short-duration transient searches are discussed, revealing that the integrated thermal emission from all large satellites does not contribute significantly to the SPT-3G survey intensity map. Measured satellite positions are found to be discrepant from their two-line element (TLE) derived ephemerides up to several arcminutes which may present a difficulty in cross-checking or masking satellites from short-duration transient searches.