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Satellite Boom Sparks Concerns Over New Problems in Space

Concern over problems such as collisions and light pollution have been increasing among government agencies, astronomers and others as the number of launched and proposed low-Earth orbit satellites surges.

(TNS) — Space is vast. But are certain parts of space in danger of becoming overcrowded with Internet satellites and cosmic junk?

Concern has been increasing among government agencies, astronomers and others as the number of launched and proposed low-Earth orbit satellites surges.

Worries center on the increased risk of collisions that create debris fields capable of taking out nearby satellites; bright reflections that harm scientific astronomy and change the night sky; atmospheric pollution from thousands of deorbiting satellites burning up every few years; and radio signal interference that blocks access for rival satellite outfits, including sovereign nations.

All this is known as carrying capacity. "This is so important and so contentious — some people say we are nowhere near carrying capacity and others are saying the constellations that have been licensed already exceed carrying capacity. So, which is right?" said Mark Dankberg, co-founder and chief executive of Viasat.

Eight years ago, there were roughly 1,300 functioning satellites in orbit. Today, that number is estimated at 7,500 and rising.

The U.S. Federal Communications Commission has pending applications for more than 60,000 new satellites.

These new satellites aim to enter orbits that already have debris circling at 17,000 mph. The European Space Agency says more than 36,000 objects with a diameter the size of a grapefruit or larger are orbiting Earth. They're joined by 1 million fast-moving particles that range in size between a pea and a grapefruit. And there are some 130 million objects smaller than a pea.

SpaceX's Starlink satellites, which have propulsion to dodge objects, are estimated to have performed an increasing number of avoidance maneuvers, said Hugh Lewis, a professor of aeronautics at the University of Southampton in the United Kingdom.

In an email to the Union-Tribune, Lewis estimated that Starlink satellites conducted 5,340 avoidance maneuvers in March alone —though it's hard to know exactly why these dodges were done.

Jonathan McDowell, a well-known astronomer who works at the Harvard–Smithsonian Center for Astrophysics, said "The more close approaches you have, the more avoidance maneuvers you're doing and the more disparate players there are — not just the number of satellites but the number of different organizations that own satellites — then it gets to the point where a collision ends up being pretty inevitable."

One collision probably isn't catastrophic. "But when you're getting one every couple of years, you very rapidly increase the amount of space debris, and you get on a path to it being really unusable in low-Earth orbit," said McDowell. "We are not there yet, but the risk is steadily increasing."

SpaceX did not respond to a request for comment. But in filings with the FCC, the company said it uses a conservative maneuver threshold that is more sensitive than the industry standard. The system is automated.

It also said it has developed collision avoidance agreements in conjunction with rival satellite operators to "facilitate physical coordination."

The company said its first-generation satellites, on average, have conducted about three collision avoidance maneuvers every six months in 2022 — many of them to avoid debris from a Russian anti-satellite missile demonstration that destroyed one of Russia's retired satellites in November 2021.

Still, China notified the United Nations in December 2021 that its space station had two close encounters with Starlink satellites and performed evasive maneuvers.

Because its satellites have propulsion to move out of the way, the FCC found Starlink's first generation of 4,400 satellites posed no collision risk.

When Starlink sought approval for 30,000 second-generation satellites — each significantly larger than its first generation— regulators tapped the brakes.

SpaceX has received approval for 7,500 second-generation satellites for now. Among the concerns are the impact of the sun's bright reflections off the satellites on telescopes used for things like tracking asteroids or Earth observation missions that take measurements of climate.

Starlink's first-generation satellites each has 600 pounds of mass and take up about 280 square feet of cross-sectional area, according to FCC filings. Its second-generation satellites each has 4,400 pounds of mass and take up 2,950 square feet.

"When you look at what's going on with these low-Earth orbit satellites, it used to be a large number of small satellites," said Dankberg, the Viasat CEO. "What's happening now is a large number of big satellites."

SpaceX has said it is working to reduce the brightness of its satellites, including with the National Science Foundation.

"I don't care about a few bright satellites," said McDowell. "They are annoying but not existential. But when you get up to 30,000 or 50,000 — those sorts of numbers — then that starts to be a real big problem for astronomy because almost every picture you take will have a satellite passing through it."

© 2023 The San Diego Union-Tribune. Distributed by Tribune Content Agency, LLC.