大量の地球低軌道通信衛星が天文学を混乱させる可能性(Massive low earth orbit communications satellites could disrupt astronomy)

2023-10-02 インペリアル・カレッジ・ロンドン(ICL)

Trail left by BlueWalker 3 over Observatorio　Astronomico Nacional, San Pedro Martir, Mexico.
Credit: I. Plauchu-Frayn

＜関連情報＞

• https://www.imperial.ac.uk/news/248038/massive-earth-orbit-communications-satellites-could/
• https://www.nature.com/articles/s41586-023-06672-7

BlueWalker3衛星の高い光学的明るさ The high optical brightness of the BlueWalker 3 satellite

Sangeetha Nandakumar,Siegfried Eggl,Jeremy Tregloan-Reed,Christian Adam,Jasmine Anderson-Baldwin,Michele T. Bannister,Adam Battle,Zouhair Benkhaldoun,Tanner Campbell,J. P. Colque,Guillermo Damke,Ilse Plauchu Frayn,Mourad Ghachoui,Pedro F. Guillen,Aziz Ettahar Kaeouach,Harrison R. Krantz,Marco Langbroek,Nicholas Rattenbury,Vishnu Reddy,Ryan Ridden-Harper,Brad Young,Eduardo Unda-Sanzana,Alan M. Watson,Constance E. Walker,John C. Barentine,Piero Benvenuti,Federico Di Vruno,Mike W. Peel,Meredith L. Rawls,Cees Bassa,Catalina Flores-Quintana,Pablo García,Sam Kim,Penélope Longa-Peña,Edgar Ortiz,Ángel Otarola,María Romero-Colmenares,Pedro Sanhueza,Giorgio Siringo & Mario Soto
Nature  Published:02 October 2023
DOI:https://doi.org/10.1038/s41586-023-06672-7

We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.

Abstract

Large constellations of bright artificial satellites in low Earth orbit (LEO) pose significant challenges to ground-based astronomy¹. Current orbiting constellation satellites have brightnesses between apparent magnitudes 4 and 6, while in the near-infrared Ks band they can reach magnitude 2². Satellite operators, astronomers, and other users of the night sky are working on brightness mitigation strategies^3,4. Radio emissions induce further potential risk to ground-based radio telescopes that also need to be evaluated. Here we report the outcome of an international optical observation campaign of a prototype constellation satellite, AST Space Mobile’s “BlueWalker 3”. BlueWalker 3 features a 64.3 m² phased-array antenna as well as a Launch Vehicle Adapter (LVA)⁵. The peak brightness of the satellite reached an apparent magnitude of 0.4. This made the new satellite one of the brightest objects in the night sky. Additionally, the LVA reached an apparent V-band magnitude of 5.5 four times brighter than the current International Astronomical Union recommendation of magnitude 7^3,6; it jettisoned on 2022-11-10 (UT), and its orbital ephemeris was not publicly released until four days later. The expected build-out of constellations with hundreds of thousands of new, bright objects¹ will make active satellite tracking and avoidance strategies a necessity for ground-based telescopes.