Detection of Spaceborne Lasers with the Pierre Auger Observatory

TL;DR

This paper demonstrates the detection of spaceborne laser signals using cosmic ray observatories, enabling atmospheric studies, instrument calibration, and satellite performance monitoring through analysis of lidar data from multiple satellites.

Contribution

It presents the first successful reconstruction of spaceborne laser shots from ALADIN and ATLID satellites at ground-based observatories, establishing a new method for calibration and atmospheric monitoring.

Findings

Successful detection of laser shots from ALADIN in 2019-2021

Initial observations of ATLID laser shots in 2024

Potential for relative calibration of cosmic ray observatories

Abstract

The detection of side-scattered ultraviolet light from spaceborne lasers with fluorescence telescopes of cosmic ray observatories offers unique opportunities for systematic studies of the aerosol content of the local atmosphere. It also enables the validation of the optical calibration of the telescopes. Additionally, these observations provide valuable ground-based monitoring of the performance of the scientific instruments aboard satellites used for Earth climate observation. Here, we report on results from the reconstruction of laser shots from the spaceborne lidar instrument ALADIN aboard the Aeolus satellite in 2019, 2020 and 2021. Furthermore, we present initial observations of laser shots from ATLID, the atmospheric lidar of the EarthCARE satellite, launched in 2024. EarthCARE's orbit is particularly well-suited for enabling laser detection within a few days at both the Pierre Auger Observatory and the Telescope Array Experiment, facilitating a relative calibration of the energy scales of these observatories.