Sun. Dec 3rd, 2023
New Concerns Raised about Large Satellite Constellations and Their Impact on Astronomy

Astronomers have expressed concerns about the potential disruption caused by groups of large satellites orbiting the Earth. An international team of scientists, including researchers from Imperial College London, published a paper in the Nature journal discussing the impact of the BlueWalker 3 satellite on astronomy.
The BlueWalker 3 is a prototype satellite belonging to AST SpaceMobile, and it is part of a planned satellite constellation designed to provide mobile and broadband services worldwide. Observations of the BlueWalker 3 have shown that it is one of the brightest objects in the night sky, even outshining the majority of stars.
The close proximity and large size of satellite constellations pose a significant risk to night sky observations, leading astronomers to raise concerns. The night sky serves as a unique laboratory for scientific experiments that cannot be conducted in terrestrial laboratories. Additionally, it is a vital part of humanity’s shared cultural heritage and should be preserved for future generations, according to Dave Clements from Imperial’s Department of Physics.
Observations taken shortly after the launch of the BlueWalker 3 in September 2022 confirmed its brightness. Data collected from various professional and amateur sites around the world, including Chile, the US, Mexico, and New Zealand, were used to calculate the satellite’s trajectory over time. This knowledge could help astronomers avoid or at least anticipate its presence in their data. However, mitigating the satellite’s brightness beyond masking its position and sacrificing data for that portion of the sky poses significant challenges.
In addition to its brightness, the BlueWalker 3’s use of radio frequencies close to those used by radio telescopes also poses a threat to radio astronomy. The existing protection measures against radio interference may not be sufficient, and further research is needed to develop strategies for protecting telescopes from the increasing number of satellites planned for launch in the coming years.
While acknowledging the importance of satellite constellations in improving global communication, the researchers emphasize the need for careful consideration of their impact on astronomy. Efforts should be made to minimize interference with astronomical observations to avoid hindering our understanding of the universe.