Analysing the Impact of Satellite Constellations and ESO’s Role in Supporting the Astronomy Community

Williams, A.; Hainaut, O.; Otárola, Angel; Tan, Gie Han; Rotola, Giuliana

doi:10.18727/0722-6691/5237

Cited by 3 publications

(1 citation statement)

References 3 publications

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“…However, these are only two of many companies that plan to create their own communications satellite constellations. In total the future may include as many as one hundred thousand satellites in LEO (Williams et al 2021). This is an exciting future for space development but carries with it multiple new challenges including space traffic management (Hiles et al 2021), conjunction and collision risks, environmental impact from rocket launches and satellite atmospheric disposal (Boley & Byers 2021), and incidental effects to astronomy (JASON Program Office 2020; Walker et al 2020b).…”

Section: Introductionmentioning

confidence: 99%

The Steward Observatory LEO Satellite Photometric Survey

Krantz,

Pearce,

Block

2023

PASP

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The Steward Observatory LEO Satellite Photometric Survey is a comprehensive observational survey to characterize the apparent brightness of the Starlink and OneWeb low Earth orbit satellites and evaluate the potential impact on astronomy. We report the results of over 16,000 independent measurements of nearly 2800 individual satellites. In addition to photometry, we also measured the astrometric position of each satellite and evaluated the accuracy of predicting satellite position with the available two-line element sets. The apparent brightness of a satellite seen in the sky is not constant and depends on the Sun-satellite-observer geometry. To capture this, we designed the survey to create an all-geometries set of measurements to fully characterize the brightness of each population of satellites as seen in the sky. We visualize the data with sky-plots that show the correlation of apparent brightness with on-sky position and relative Sun-satellite-observer geometry. The sky-plots show where in the sky the satellites are brightest. In addition to visual magnitudes, we also present two new metrics: the expected photon flux and the effective albedo. The expected photon flux metric assesses the potential impact on astronomy sensors by predicting the flux for a satellite trail in an image from a theoretical 1 m class telescope and sensor. The effective albedo metric assesses where a satellite is more reflective than baseline, which ties to the physical structure of the satellite and indicates the potential for brightness-reducing design changes. We intend to use this methodology and resulting data to inform the astronomy community about satellite brightness. Observing programs use a variety of telescopes and instruments and look at different parts of the sky. With the expected photon flux metric and a complete all-sky characterization of satellite brightness, observers can evaluate the potential impacts to their projects and possibly avoid the worst effects.

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Section: Introductionmentioning

confidence: 99%

The Steward Observatory LEO Satellite Photometric Survey

Krantz,

Pearce,

Block

2023

PASP

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CLOWN: The PASO Cloud Detection for Optimization of Automatic Optical Surveys

Gonçalves,

Coelho,

Barbosa

et al. 2024

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Orbiting space objects have become in the last decade a major nuisance impacting ground astronomy and orbiting space assets, from observatories to satellites and space stations. In particular with the rise of the satellite population in Low Earth Orbits, space objects are becoming an even bigger threat and a strong problem to astronomical observations. To tackle these threats, several coordinated surveillance networks composed of dedicated sensors (telescopes, radars, and laser ranging facilities) track and survey space objects, from debris to active satellites. As part of the European Space Surveillance & Tracking network, Portugal is developing the Pampilhosa da Serra Space Observatory, with both radio and optical telescopes dedicated to the Space Situational Awareness domain, deployed at a Dark Sky destination. To optimize telescope survey time, we developed CLOud Watcher at Night (CLOWN), an application interface that automatically monitors clouds in real time. This software can correctly trace cloud positions in the sky and provide accurate pointing information to the observation planning of the optical telescope to avoid cloudy areas. CLOWN only requires the use of an all-sky camera, which is already a norm in observatories with optical telescopes and can be used with any camera, including those for which no information about its model specification do exist. CLOWN does not require great computing power, and it does not require the installation of additional equipment. CLOWN results are very promising and confirm that the app can correctly identify clouds in a variety of different conditions and cloud types.

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Impact of the SpaceX Starlink Satellites on the Zwicky Transient Facility Survey Observations

Mróz

Otárola

Prince

et al. 2022

ApJL

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There is a growing concern about an impact of low-Earth-orbit (LEO) satellite constellations on ground-based astronomical observations, in particular, on wide-field surveys in the optical and infrared. The Zwicky Transient Facility (ZTF), thanks to the large field of view of its camera, provides an ideal setup to study the effects of LEO megaconstellations—such as SpaceX’s Starlink—on astronomical surveys. Here, we analyze the archival ZTF observations collected between 2019 November and 2021 September and find 5301 satellite streaks that can be attributed to Starlink satellites. We find that the number of affected images is increasing with time as SpaceX deploys more satellites. Twilight observations are particularly affected—a fraction of streaked images taken during twilight has increased from less than 0.5% in late 2019 to 18% in 2021 August. We estimate that once the size of the Starlink constellation reaches 10,000, essentially all ZTF images taken during twilight may be affected. However, despite the increase in satellite streaks observed during the analyzed period, the current science operations of ZTF are not yet strongly affected. We also find that redesigning Starlink satellites (by installing visors intended to block sunlight from reaching the satellite antennas to prevent reflection) reduces their brightness by a factor of 4.6 ± 0.1 with respect to the original design in g, r, and i bands.

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Analysing the Impact of Satellite Constellations and ESO’s Role in Supporting the Astronomy Community

Cited by 3 publications

References 3 publications

The Steward Observatory LEO Satellite Photometric Survey

The Steward Observatory LEO Satellite Photometric Survey

CLOWN: The PASO Cloud Detection for Optimization of Automatic Optical Surveys

Impact of the SpaceX Starlink Satellites on the Zwicky Transient Facility Survey Observations

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