Hight Altitude Balloon Light at Night experiment (HABLAN)

Multispectral and Multiangular Remote Sensing of the Light at Night from High Altitude Balloon

Project summary

In collaboration with the Canadian Space Agency (CSA) and the European Space Agency (ESA) in the framework of the STRATOS program, we launch multiple DSLR systems to observe the multiangular and spectral properties of the installed luminaires from an altitude of 36 km. STRATOS project consists of high altitude balloon flights to perform a variety of near space experiments. For HABLAN-I, two Sony A7S cameras were attached to a gimbal in order to assure a nadir pointing stability. The balloon took off at Timmins (ON, Canada) in August 2019 for its first flight. The experiment took place around the new moon. One of the two cameras is equipped with a 50mm lens, assuring the collection of high-resolution images (6 m per pixel). Data, such as multispectral radiance of light points and spectral type recognition, ground cover, and obstacles properties will be derived from this camera. The other camera is equipped with an 8mm fisheye lens so that the angular function of the luminaires will be sampled up to almost 90-degrees from zenith. Close to the flight, ground-based data were acquired. For instance, we used the LANcube multiangular and multispectral sensor in a roadrunner mode to map the light at night all over the overflown region. We also sampled the sky brightness with a third A7S camera with 24mm lens and a robotic mount.

For its second version, HABLAN-II will be equiped with at least 3 Sony A7S cameras. All of them with 24 mm T1.5 lenses. The alignment of the cameras will allow the acquisition of data from nadir to up to 60 degrees above horizon. Above horizon images will be used to determine the orientation of the device and will serve as a calibration tool thanks to stars that will be visible. Since the system no longer have a fisheye lens, the camera set will be rotated with a step motor to cover all possible orientations. The nadir footprint of a pixel is 10 m. This resolution is enough to resolve individual light fixtures along with many buildings. We expect the system to be launched in August 2021.

Résumé du projet financé par le programme VITES 2020 de l'Agence Spatiale Canadienne

19FACSHB02 - La pollution lumineuse survient lorsque la lumière artificielle nocturne (LAN) est émise dans l'environnement à des niveaux et/ou à des moments qui ont un effet perturbateur sur celui-ci. Plusieurs études ont établi des liens statistiques entre la LAN et le risque lié à certaines maladies telles que les cancers hormonaux dépendants (CHD). Des études récentes réalisées avec les images couleur prises par les astronautes de la station spatiale internationale démontrent que la composante bleue de la lumière est fortement liée à la survenue des CHD.

Les principaux objectifs du projet incluent la mise au point d’une technique de télédétection de la LAN depuis la stratosphère, raffiner l’analyse des données acquises au sol et valider la méthode de télédétection et exploiter les données de télédétection dans un modèle numérique pour en déduire les risques associés pour la santé des Canadiens. La télédétection stratosphérique permet de mesurer de larges territoires en peu de temps. Ces mesures seront effectuées à bord des vols de ballons stratosphériques alors que les mesures terrain seront faites en disposant le LANcube (un appareil que l’équipe a mis au point) sur un véhicule motorisé parcourant le territoire survolé par le ballon.

Summary of the project funded by the Canadian Space Agency program VITES 2020

19FACSHB02 - Light pollution occurs when Artificial Light at Night (ALAN) is emitted into the environment at levels and/or at times that have a disturbing impact on it. Several studies have established statistical links between ALAN and the risk associated with certain diseases such as hormone-sensitive cancers (HSC). Recent studies based on colour images taken by astronauts on the International Space Station demonstrate that the blue component of light is strongly linked to the occurrence of HSC.

The main objectives of the project include developing an ALAN remote sensing technique from the stratosphere, refining the analysis of data acquired on the ground, validating the remote sensing method, and using the remote sensing data in a digital model in order to identify the associated risks to the health of Canadians. Stratospheric remote sensing enables the measurement of large areas within a short timeframe. These measurements will be made on board flights of stratospheric balloons, while field measurements will be made by placing the ALANcube (a device developed by the project team) on a motorized vehicle traversing the territory overflown by the balloon.

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