World’s largest communication satellite is a photobombing menace, astronomers warn

By Harry Baker,
Published by Live Science, 6 December 2022

A giant new communications satellite that outshines almost all the stars in the night sky is obscuring telescopes’ views of the universe, scientists warn. 

The massive orbiting “cell phone tower,” known as BlueWalker 3, is creating both visible and invisible interference that could “severely hamper progress in our understanding of the cosmos,” representatives of the International Astronomical Union (opens in new tab) (IAU) said in a statement.

BlueWalker 3 is a prototype antenna that was designed and built by Texas-based communications company AST Space Mobile. The satellite launched into low-Earth orbit on Sept. 10 and unfurled its massive communications array on Nov. 14, Live Science’s sister site reported. The mirror-like dish has a surface area of around 693 square feet (64 square meters), making it the biggest commercial communications array ever launched into orbit.

However, BlueWalker 3 has one glaring issue: The satellite’s enormous dish is reflecting massive amounts of sunlight back to Earth’s surface, the IAU’s Center for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference (CPS) said in the statement. The astronomers released a number of timelapse photos captured by observatories from around the world showing the satellite photobombing the night sky — appearing as a continuous bright white line across the sky.

“This satellite has become one of the brightest objects in the night sky,” IAU representatives wrote in the statement, “more so than other constellation satellites and at times as bright as some of the most recognizable stars.”

BlueWalker 3 unfurled its 693 square-foot array on Nov. 14.  (Image credit: AST Space Mobile)

And the supersized satellite is not just blocking telescopes’ optical views of the universe. The IAU also warns that the cell phone signals emitted by the communications satellites could create significant interference for radio telescopes too.

“These orbiting transmitters, which are not subject to the same radio quiet zone restrictions as ground-based cellular networks, have the potential to severely impact radio astronomy research,” IAU representatives wrote.

BlueWalker 3 is the latest flashpoint in an ongoing debate about astronomical interference caused by communications satellites, which started when SpaceX launched its first Starlink satellites in 2019. (There are now more than 2,000 Starlink satellites orbiting our planet, which could rise to many as 12,000 in the coming years). But BlueWalker 3’s enormous size could prove a major turning point in the discussion.

“BlueWalker 3 is a big shift in the constellation satellite issue and should give us all reason to pause,” Piero Benvenuti (opens in new tab), director of the IAU CPS, said in the statement. 

Trails in the night sky left by BlueWalker 3 are juxtaposed against the Nicholas U. Mayall 4-meter Telescope at Kitt Peak National Observatory in Arizona (Image credit: KPNO/NOIRLab/IAU/SKAO/NSF/AURA/R. Sparks)

A single BlueWalker 3 satellite in orbit may only be a slight nuisance to astronomers at present, but AST plans to launch a fleet of “more than 100 similar or even larger satellites” in the future as it attempts to build a worldwide mobile network, IAU representatives wrote. This could make it almost impossible for astronomers to avoid the satellites’ photobombing glare. 

IAU representatives wrote that the astronomical community acknowledges commercial satellites will play an important role in improving global communication systems, but argues that their deployment “should be conducted with due consideration of their side effects and with efforts made to minimize their impact on astronomy.” 

The IAU’s warning comes after the U.S. Federal Communications Commission (FCC) announced on Nov. 3 a proposal to create the “Space Bureau and Office of International Affairs,” which will help to address the emerging issues surrounding large satellite constellations in the U.S. and globally, according to IAU (opens in new tab). 

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