Since the launch of the first Starlink spacecraft in 2019, SpaceX’s satellites have had to move more than 50,000 times to avoid collisions. The staggering increase in the number of Starlink collision avoidance maneuvers over the past six months raises concerns about the long-term stability of satellite operations as thousands of new spacecraft are expected to enter orbit in the coming years.

According to a report by SpaceX to the US Federal Communications Administration, Starlink broadband satellites They had to deviate from SpaceX more than 25,000 times between December 1, 2022 and May 31, 2023, to avoid potentially dangerous encounters with other spacecraft and orbital debris. Commission (FCC) on 30 June. That’s roughly double the number of evasion maneuvers reported by SpaceX in the six months from June to November 2022. Since the launch of the first Starlink spacecraft in 2019, SpaceX’s satellites have had to move more than 50,000 times to avoid collisions.

The sharp increase in the number of maneuvers has an exponential curve, worrying experts, raising concerns that the safety of operations in orbit may soon spiral out of control.

“Now the number of maneuvers is increasing exponentially,” Hugh Lewis, an astronaut professor at the University of Southampton in England and a leading expert on the impact of mega-constellations on orbital safety, told Space.com. “It doubled every six months, and the problem with exponential trends is that they get to very large numbers very quickly.”

1 million maneuvers by 2028

Data compiled by Lewis shows that Starlink satellites performed 2,219 collision avoidance maneuvers in the first half of 2021. In the six-month period ending December 2021, that number rose to 3,333, and then doubled to 6,873 between December 2021 and June 2022. In the second half of 2022, SpaceX had to change the orbit of its satellites 13,612 times to avoid potential collisions. . In its latest report to the FCC, the company announced 25,299 collision avoidance maneuvers, with each satellite moving an average of 12 times over the past six months.

“Now, every six months, the number of maneuvers performed doubles,” Lewis said. “It’s grown 10x in just two years, and if you guessed it, you’ll have 50,000 in the next six months, then 100,000, then 200,000.”

If this trend continues, by 2028 Starlink satellites will have to maneuver about a million times every six months to minimize the risk of orbital collisions. And Lewis doesn’t expect that growth to slow any time soon. SpaceX has now deployed about a third of its planned first-generation fleet of 12,000 spacecraft and regularly launches more than 800 satellites per year; this is a trend that is expected to continue in the foreseeable future.

However, the first-generation Starlink grouping is just the beginning. The FCC has partially approved plans for the second-generation Starlink array, which can consist of up to 30,000 satellites. With the Kuiper project, Amazon and Guowang and other players around the world, including China, are trying to secure their orbital slots with their respective regulators.

More than 1.7 million satellites are registered with the International Telecommunication Union, the UN agency that oversees satellite use of radio frequencies, according to Joanne Wheeler, satellite regulatory expert at Alden Legal and head of the UK Satellite Finance Network. . While all these plans are unlikely to come true, the numbers are so high that experts like Lewis question whether order can be maintained in orbit.

“If we expect to have 100,000 active satellites by the end of this decade, I suspect the number of combined maneuvers to be performed by all spacecraft operators will be enormous,” Lewis said. “You’re maneuvering to mitigate high-risk events, but that’s like driving down the highway and making a turn every 10 meters to avoid a collision. It has to be dangerous.”

According to the European Space Agency, There are currently about 10,500 satellites orbiting our planet, of which 8,100 are operational. Everything has become very cramped relatively recently. For example, in 2019 according to Statista, there were only about 2,300 active satellites orbiting the planet. The main driver of growth is undoubtedly Starlink, the largest satellite constellation ever assembled.

New satellites aren’t the only reason for the increased need for orbital rotation. Number space debris – defunct spacecraft, old rocket stages and miscellaneous parts – also continue to grow, making it harder for operators to maintain spacecraft.

Currently, SpaceX is conducting an evasion maneuver when orbital models show that the probability of one of the Starlink satellites passing in the path of another object exceeds 1 in 100,000. This threshold is 10 times lower than the standard provided by NASA and other international organizations.

But Lewis doubts SpaceX can maintain such a high standard as the number of “connection notices” continues to grow. He adds that, despite the company’s efforts, the risk of collision will now increase.

Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics and another frequently heard caveat in the satellite mega-constellation discussion, agrees with Lewis: “SpaceX is confident they can handle the increased maneuvering load,” McDowell told Space.com. . “I’m not sure SpaceX adequately accounts for non-statistical errors (possibility of independent and unpredictable errors leading to a bad outcome – a collision), so I’m concerned that we’re operating at the border of what’s safe.”

Starlink is based on an autonomous collision avoidance system that instructs satellites to maneuver based on patterns of orbital trajectories of objects in space. These models give several days’ notice and may not always be accurate. Also, other factors such as changes in density can affect the accuracy of these calculations. earth’s atmosphere at high altitudes, originates from space weather. Source