WASHINGTON – The European Space Agency said that on September 2, it was maneuvering one of its Earth science satellites to avoid a potential collision with a SpaceX Starlink satellite, the agency said for the first time that it had to maneuver to avoid a satellite, Broadband related
In a series of tweets from his account at ESA Operations, the agency stated that the Aeolus satellite was maneuvering to avoid a potential close approach to the Starlink satellite, which identified in one graph as Starlink 44.
in the morning , @ESA & # 39; #Aeolus From my observation satellite launches its ejectors, moving it from a collision course with @SpaceX a satellite into their # Starlink constellation pic.twitter.com/bn2GH91900S91900S199S919S919S919S19 ESA Operations (@esaoperations) September 2, 2019
"Experts in our #SpaceDebris team calculated the risk of a collision between t hese two active satellites, determining the safest option for #Aeolus would be to increase its height go over the @SpaceX satellite, "the agency tweeted. This maneuver took place about half orbit before the nearest approach, and the agency confirmed that the spacecraft was operating normally after the time of the nearest approach.
ESA provided few other details about the circumstances of the potential coupling, including how close the two were to spacecraft to approach each other during the closest approach, the likelihood of a collision, and what communications ESA had with SpaceX or others. ESA did not respond to an email from SpaceNews requesting comment. Sept. 2. The ESA Operations Twitter account stated that an article with more information would be published on the ESA website, but that article was not published until the end of September 2.
SpaceX also did not respond to an email requesting comment on the potential conjuncture of September 2, which was the Labor Day holiday in the United States.
According to a list of links called satellite orbital reports evaluating threatening space encounters (SOCRATES) maintained by the Center for Space Standards and Innovation, Aeolus was expected to have a close approach shortly after 7 a.m. on Eastern 2 September with a satellite identified as "Starlink AV" for its international designation 2019-029AV. The two satellites were projected to reach about four kilometers from each other at a relative speed of 14.4 kilometers per second. However, the SOCRATES data predicted a very low collision probability – less than one in one million – which would typically be well below the threshold for an avoidance maneuver.
This Starlink satellite is in orbit much lower than most of the other 60 Starlink satellites launched by SpaceX in May. According to the Space Track database maintained by the US Air Force, Starlink AV is in orbit that varies between 311 and 345 kilometers; the next lowest satellite is an orbit from 361 to 397 kilometers. The Aeolus, launched in 2018, is in orbit at altitudes between 308 and 314 kilometers.
Most of the rest of Starlink satellites launched into orbit at an altitude of about 450 kilometers have since moved to their operational altitude of about 550 kilometers. In June, SpaceX announced plans to deliberately de-activate two of Starlink's satellites as a test of the spacecraft's propulsion system, suggesting that Starlink AV could be one of those satellites. SpaceX also said in June that three of the 60 satellites did not respond to commands and are believed dead.
In its series of maneuvering tweets, ESA suggests that a "manual" approach to avoid potential collisions will not be resilient once more satellites, such as those in Starlink and other planned megacostellations, are in orbit. "These avoidance maneuvers take a lot of time to prepare – from determining the future orbital positions of all functioning spacecraft to calculating the risk of collision and the potential results of different actions," the agency said.
ESA stated that it wanted to rely. more on artificial intelligence to decide whether and how to avoid avoidance maneuvers, and there is a proposal to fund similar work for the agency's member states to be considered at the Space19 + ministerial meeting in November. This is part of a broader space security initiative that also includes improved space weather forecasting and a planetary defense mission called Hera.
SpaceX also stated that it plans to use autonomous systems to avoid collisions. "Our satellites automatically maneuver around any orbital debris," SpaceX CEO Elon Musk told reporters in May, shortly before Starlink launched. Musk said SpaceX will upload airborne tracking data to satellites, "and they use their pushers to automatically maneuver around everything NORAD is tracking."
"I think we have a really good decision to make sure we don't create orbital debris," he added, noting that the relatively low altitude of Starlink satellites limits their orbital life. It was not clear if this stand-alone avoidance system was active on Starlink, which is scheduled to approach Aeolus, or other active Starlink satellites.
While ESA sounded worried by the close approach, others in the industry were dissatisfied with the attention it received. "Hmmm. We move our satellites an average of once a week and don't issue a press release to tell who we've been maneuvering with," tweeted Matt Dash, CEO of Iridium, which operates a constellation of 75 next-generation satellites in low Earth orbit. ] Um We move our satellites on average once a week and don't release a press release to tell who we've been wandering around with… https://t.co/L4XyoQVydP records19659002matra— Matt Desch (@IridiumBoss) September 2, 2019  ] However, Desch has previously expressed concerns about threats to the sustainability of space, p "Mega-constellations, especially if these satellites have a high failure rate." We are creating an environment that can turn LEO into an environment that is not sustainable, he warned in a June forum organized by the Secure World Foundation.  He added that he is still happy that SpaceX has decided to put its Starlink satellites in a lower orbit than originally suggested, meaning they will remain in orbit for a shorter period, even if they are not intentionally discouraged. "It's a very responsible decision," he said.