Megaconstellations are corrupting astronomers’ view of space and could impact planetary defences against incoming space debris
A union of astronomers is taking action to protect the study of the night sky from the effects of the thousands of satellites launched by companies such as SpaceX.
Huge systems of satellites known as megaconstellations, including the thousands Elon Musk’s private space company has launched to create the Starlink network, leave bright streaks across images taken by astronomers’ telescopes.
Starlink satellites are leaving 35 more traces in photographs than they were two years ago, with one now being found every ten days.
Now, the International Astronomical Union has established a new organisation to try to combat this phenomenon.
The new Centre for the Protection of the Dark and Quiet Skies from Satellite Constellation Interference – which works alongside the US National Optical-Infrared Astronomy Research Laboratory (NOIRLab) and the Square Kilometre Array Organisation (SKAO) in the UK – was set up with the intention to “unify voices across the global astronomical community with regard to the protection of the dark and quiet sky from satellite constellation interference”.
The concerns, SKAO’s Federico Di Vruno told the BBC, were that science could become a “free-for-all” if too many megaconstellations cluttered the sky.
As well as Starlink’s aim to put 40,000 satellites in space – which could result in every twilight image taken by astronomers being corrupted by four bright white streaks – OneWeb in the UK and Amazon’s Project Kuiper also aim to launch their own networks.
The resulting pollution could influence radio detectors that study the universe after the Big Bang, as well as planetary defences against incoming asteroids.
“At optical wavelengths, observations with long exposure times will be affected the most, particularly in the hours close to twilight, and observing low on the horizon. A prime example would be the research on potentially hazardous asteroids done by the International Asteroid Warning Network,” said Mr Di Vruno.
NOIRLab’s Connie Walker elaborated on the concerns. “As the number of satellites continues to grow, astronomy is facing a watershed moment of increasing interference with observations and loss of science,” she said.
“By the end of a decade, more than 5,000 satellites will be above the horizon at any given time at a typical dark-sky observatory location. A few hundred to several thousand of these satellites will be illuminated by the sun. These satellites will be detectable by even the smallest optical or infrared telescopes, depending on the hour of the night and the season.”
This is not the first time that calls have been made to protect astronomical observations from interference caused by satellites. In August 2020, hundreds of astronomers warned that megaconstellations would be “extremely impactful to the most severely affected science programmes”.
SpaceX has deployed a variety of tactics to reduce the visibility of its satellite network, including painting them black and twisting the position of their solar panels to make them less reflective. It appears that these techniques have not proved effective enough.
