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2023-10-06

Sputnik BlueWalker 3 is one of the brightest objects in the night sky

A new class of gigantic satellites designed to beam phone signals from space has astronomers alarmed about impacts on observations. A recent study of the experimental BlueTide 1 satellite revealed it may be the most optically disruptive object ever launched.

At 65 square meters in size, BlueWalker 3 features a mammoth phased array of transmitters and receivers to provide direct mobile connectivity. Analysis shows its reflective surfaces make BlueWalker 3 nearly as bright as Polaris when orbiting overhead.

This magnitude 0.7 luminosity exceeds every natural night sky object except the 14 brightest stars and planets. Astronomers liken its light pollution impact to a new artificial Venus suddenly appearing in the sky.

The findings compound fears that satellite mega-constellations could severely degrade telescope observations. Streaks from dense batches of satellites already ruin many long-exposure images. But next-generation communications satellites may also interfere at radio frequencies vital to radio astronomy.

BlueWalker 3 plans to launch a 160-satellite grid that could affect radio signals from 14 to 42 GHz. This includes spectral bands critical for studies of star formation, galaxy evolution, and the cosmic microwave background. Astronomers warn entire fields of research are jeopardized.

In response, operators such as BlueTide are collaborating with astronomers to identify "safe zones" in the radio spectrum and minimum elevation angles above the horizon. Satellite reflections can also be reduced by sunshielding panels and Earth-facing dark coatings.

But astronomical groups stress that mitigating measures must be tested extensively and implemented proactively before launching swarms of disruptive satellites. The outcry over BlueWalker 3 highlights the urgent need for solutions balancing connectivity advances from orbit with impacts visible from the ground.

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