SpaceX reported that despite the constellation’s growth, the number of close encounters between its satellites and other orbital objects has not increased over the past six months.
Space sustainability experts say the development is good news but warn that the reduction in evasive maneuvers is likely just a deviation from the long-term upward trend.
Twice a year, SpaceX reports to the US Federal Communications Commission (FCC) how many times its satellites have had to divert paths to avoid possible collisions with other spacecraft and space debris. Rocket company presented its latest report “Semi-annual constellation status report” December 29, 2023 covers the period between June 1, 2023 and November 30, 2023.
During this period, Starlink satellites had to perform 24,410 collision avoidance maneuvers, which is the equivalent of six maneuvers per spacecraft. During the previous reporting period, which covered the six months until May 31, 2023, the constellation’s satellites had to move 25,299 times. The data shows that although the Starlink constellation has grown by nearly 1,000 spacecraft in the past six months, its satellites made fewer evasive maneuvers during that period than in the previous half-year.
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Previously, the number of maneuvers doubled every six months as the constellation grew; This was a trend that experts expected to continue and were concerned about.
Hugh Lewis, a professor of astronautics at the University of Southampton in the United Kingdom who has been studying the effects of megaconstellations on orbital security for several years, told Space.com that the apparent deviation from the previous trend could be due to natural causes. “variability” and improvements in the accuracy of satellite positioning data available to satellite operators.
“We’ll have to wait until the next reporting period to see what happens, but it’s good news,” Lewis said. “But when we look at the figures for the whole year, we can see that they had to carry out approximately 50,000 maneuvers, which is still a very high figure and slightly above last year’s value.”
Starlink satellites make autonomous maneuvering decisions based on information provided by the US Space Force and US commercial space situational awareness company LeoLabs. The satellite will move when available data indicates that the chance of a Starlink satellite hitting another spacecraft or space debris is less than 1 in 100,000. SpaceX emphasizes that its approach is much stricter than most other operators, which only move spacecraft when the risk of collision exceeds 1 in 10,000.
Dan Oltrogge, chief scientist at US space situational company COMSPOC, told Space.com that he expects the number of evasive maneuvers to increase as more satellites are planned to be launched in the coming years.
“We’ve seen a pretty dramatic increase in close approaches in the last five years,” Oltrogge said. “There has been a fivefold increase overall, and encounter rates will continue to increase as more satellites are added to the mix and more debris builds up in the space population.”
SpaceX currently operates more than 5,250 Starlink satellites; this is less than half of the planned first-generation constellation of 12,000 spacecraft. The company ultimately wants to expand its fleet to more than 40,000 satellites.
Lewis added that although previous forecasts showed Starlink satellites could need to perform more than a million maneuvers in half a year as early as 2028, the new data predicts much more moderate growth, with around a hundred thousand maneuvers needed in six months by the end of the year. of the decade.
“There are still a lot of maneuvers that need to be done,” Lewis said. “I still have concerns about whether we can operate that many satellites safely. There is a risk because there are so many of them.” [close approach] Some of the incidents may result in a collision at some point.”
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Orbital collisions are a major threat to humanity’s ability to safely use space technology. Each collision can produce thousands of fragments that can remain in orbit for long periods of time and threaten other spacecraft.
But experts praise SpaceX for its tough stance and public sharing of information with other operators. They hope other spacecraft operators will follow suit.
“We need to approach this on all fronts,” Oltrogge said. “We must try to get the most accurate data possible on the positions of satellites, dead payloads, and all other debris in space. We need to share our data as much as possible between operators, because this improves everyone’s location information so we can get rid of evasive maneuvers that we don’t need in the first place.”