May 9, 2024

Drowning Stars: BlueWalker 3’s Unprecedented Impact on Night Sky Observations

A current research study on the BlueWalker 3 satellites impact on astronomy underscores concerns about brightness and radio disturbance, prompting require pre-launch assessments and protective measures as industrial satellite releases increase. Credit: AST SpaceMobile
Initial Observations and Findings
BlueWalker 3 was released into low Earth orbit on September 10, 2022, by AST SpaceMobile as a model for a planned constellation of over a hundred similar satellites meant for use in mobile interactions. Observations made shortly after launch revealed that the satellite was amongst the brightest items in the sky.
The recently released information show an abrupt boost in the brightness of BlueWalker 3 over a period of 130 days, coinciding with the complete unfolding of the antenna variety and followed by changes over the subsequent weeks. The paper likewise exposes a relationship between the differing brightness and other factors after unfolding, such as the satellites height above the horizon and the angle in between the observer, the satellite, and the Sun. A subset of the observations were also utilized to calculate the satellites trajectory over time.
The BlueWalker 3 satellite captured on April 3, 2023. The optical brightness of the 8 meter x 8 meter satellite– one of the brightest items in the night sky having reached a peak brightness of magnitude 0.4– is displayed here as it travels throughout the stellar background. For contrast, two fainter satellites can also be seen in the video footage; Starlink-4781 (in front of BlueWalker) and Starlink-4016 (paralell and a little behind BlueWalker in a couple of frames). Credit: Delft Technical University/M. Langbroek.
Satellite Components and Ground-based Challenges.
Additionally, the launch car adapter attached to BlueWalker 3 was observed decoupling from the satellite. This element reached magnitude 5.5, going beyond optimum brightness recommendations set out by the International Astronomical Union to prevent the worst impacts of satellites on optical astronomy.
” These outcomes show a continuing trend towards bigger, brighter commercial satellites, which is of specific concern provided the plans to release a lot more in the coming years,” says the research studys co-author Siegfried Eggl from the CPS and the Department of Aerospace Engineering at the University of Illinois at Urbana-Champaign (UIUC). “While these satellites can contribute in improving interactions, it is crucial that their interruptions of scientific observations are reduced. This could ideally be accomplished through continuing cooperation on mitigation efforts, or, if that is not successful, through a requirement for pre-launch impact evaluations as part of future introducing permission processes.”.
A picture of the 8 meter x 8 meter BlueWalker 3 satellite as seen from the ground. Credit: M. Tzukran.
Thinking About Radio Frequency Interference.
While some telescopes are located within designated radio-quiet zones, the constraints in location to maintain these locations presently apply only to terrestrial transmitters, so they are not always secured from satellite transmission. Additional research is therefore required to establish techniques for safeguarding existing and future telescopes from the various satellites planned for launch over the next decade.
Stabilizing Progress with Preservation.
” The huge community understands the requirement for higher connectivity and improvements to Internet access, particularly for underserved and rural communities. Nevertheless, that progress has actually to be balanced against the negative effect that intense satellites can have on the night sky. This is a worldwide concern, because satellites approved by any country are noticeable in the night sky across the world, highlighting the importance of global coordination,” states the research studys co-author Jeremy Tregloan-Reed from the Instituto de Astronomía y Ciencias Planetarias, Universidad de Atacama Chile, CLEOsat and the CPS.
Observations of BlueWalker 3 will continue, with plans by astronomers to observe its thermal emission later this year. Astronomers will continue to discuss this topic at the upcoming IAU Symposium: Astronomy and Satellite Constellations: Pathways Forward in October.
For more on this research, see Massive Satellite Outshines All but the Brightest Stars.
Notes.

Reference: “The high optical brightness of the BlueWalker 3 satellite” by 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 and Mario Soto, 2 October 2023, Nature.DOI: 10.1038/ s41586-023-06672-7.

Scientists, consisting of astronomers from the International Astronomical Union Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference (IAU CPS), have actually published a paper in Nature examining the comprehensive effect of the BlueWalker 3 satellite on astronomy. Building on preliminary observations from quickly after its launch, these new outcomes match the preliminary understanding of this uncommon satellite and the paper contains information of how the satellites brightness changes over time and the presence of rejected hardware. The paper likewise exposes a relationship in between the differing brightness and other elements after unfolding, such as the satellites height above the horizon and the angle between the observer, the satellite, and the Sun. The BlueWalker 3 satellite recorded on April 3, 2023. For comparison, 2 fainter satellites can likewise be seen in the video; Starlink-4781 (in front of BlueWalker) and Starlink-4016 (paralell and somewhat behind BlueWalker in a couple of frames).

Routes in the night sky left by BlueWalker 3 over the Observatorio Astronomico Nacional, San Pedro Martir, Mexico, observed on November 12, 2022. The breaks in the path are triggered by breaks in between the direct exposures that were stacked to produce this image. Credit: I. Plauchu-Frayn
New Nature paper contains the outcomes of global observing campaign conducted over 130 days.
Researchers, consisting of astronomers from the International Astronomical Union Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference (IAU CPS), have actually released a paper in Nature examining the comprehensive impact of the BlueWalker 3 satellite on astronomy. Building on initial observations from soon after its launch, these brand-new results complement the initial understanding of this uncommon satellite and the paper consists of information of how the satellites brightness modifications over time and the visibility of jettisoned hardware. With business planning to deploy more commercial satellites in the coming years, this paper highlights the requirement for pre-launch effect evaluations.
” The disturbance of satellites in astronomy has actually ended up being an increasingly pressing concern over the last couple of years,” commented very first author Sangeetha Nandakumar from the Instituto de Astronomía y Ciencias Planetarias, Universidad de Atacama Chile.

The information show the altering brightness over the course of 130 days, from an apparent magnitude of 6 (prior to unfolding) to an apparent magnitude of 0.4.