New Delhi: The European Space Agency (ESA) has claimed that it has had to perform a collision avoidance manoeuvre to prevent its satellite from crashing into a satellite operated by SpaceX in its Starlink constellation.
In a series of tweets on Monday, the ESA said that it was compelled to fire the thrusters of its Aeolus Earth observation satellite to increase its altitude and avoid a potential collision with a SpaceX satellite in the Starlink constellation. The Aeolus returned to its operational orbit after the manoeuvre, which took place 320 km above the earth.
This morning, @ESA‘s #Aeolus Earth observation satellite fired its thrusters, moving it off a collision course with a @SpaceX satellite in their #Starlink constellation pic.twitter.com/bn2GHnSoFI
— ESA Operations (@esaoperations) September 2, 2019
According to Forbes, SpaceX refused to move its satellite after the US military, which monitors space traffic, alerted it to the impact risk.
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The ESA claimed that collision avoidance manoeuvres are very rarely undertaken and that the vast majority of manoeuvres are performed to prevent collisions with dead satellites or bits of space debris. The ESA further pointed out that such manoeuvres are time-consuming and involve determining the future orbital positions of all functioning spacecraft and calculating the risk of collision based on that.
It is very rare to perform collision avoidance manoeuvres with active satellites. The vast majority of ESA avoidance manoeuvres are the result of dead satellites or fragments from previous collisions#SpaceDebris pic.twitter.com/mjbdoFfCPa
— ESA Operations (@esaoperations) September 2, 2019
Mega-constellations like Starlink comprise hundreds or even thousands of satellites, and so the ESA noted that it was preparing to automate the entire process using artificial intelligence.
The Aeolus satellite was launched on August 22, 2018, as a part of a joint initiative of the European Union and ESA to track environmental damage, aid disaster relief operations and improve the quality of weather-forecasting.
Speaking to Forbes, the head of the Space Debris Office at ESA Holger Krag said that the risk of collision between the two satellites was one in 1,000 – ten times higher than the threshold that necessitates a collision avoidance manoeuvre. Krag further went on to say that after SpaceX refused to take action, the ESA decided to react.
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The Aeolus satellite, which was launched on August 22, 2018, as a part of a joint initiative of the EU and ESA to track environmental damage, aid disaster relief operations and improve the quality of weather forecasting, had occupied that particular region of space nine months before SpaceX launched its first batch of 60 internet-beaming Starlink satellites on May 23.
The 60 satellites launched are the first of nearly 12,000 satellites that SpaceX plans to put into orbit around the earth. to provide satellite-based internet service to underserved regions across the globe. Amazon’s Jeff Bezos is also pushing to provide internet access around the globe via thousands of satellites in low Earth orbit under Project Kuiper.
Several experts are concerned about the increase in space debris that SpaceX’s Starlink constellation will contribute. A study by NASA recommended that future satellites be taken out of orbit as soon as they complete their missions in order to keep the risk of in-space collisions to a low.
Previously, SpaceX chief executive Elon Musk had stated that the company planned to use autonomous systems to avoid collisions. “Our satellites automatically manoeuvre around any orbital debris,” he said, speaking to SpaceNews.