Starlink: 5% of satellites fail in orbit

SpaceX reports that three of the controversial 60 Starlink satellites have failed in orbit as the company heads towards the first test transmission of its ambitious space web constellation.

In a press release, the American company revealed that 57 of its Starlink satellites are correctly communicating with ground stations. Of these, 45 reached the desired altitude of 550 kilometers using their onboard propulsion systems, five were still gaining altitude from initial orbits of 440 kilometers, and another five were still in testing before doing the same.

The company also revealed that two satellites would be deliberately taken out of orbit “to simulate an end-of-life device”. Finally, the company said that three of its satellites are “no longer in service” and would have to “passively deorbit” from their current altitude of around 440 kilometers, with the loss of contact meaning the satellites can no longer use their systems. propulsion systems to manually de-orbit.

The launch of these first 60 Starlink satellites took place about a month ago, on May 23. Since then, SpaceX has been testing its capabilities and should soon begin examining its terrestrial Internet relay performance. In a statement, the company said it would test its latency “by streaming videos and playing high-bandwidth video games.”

But the failure rate of satellites so far is likely to become a cause for concern. Each satellite does not have an orbit backup system in the event of failure, which means that the three satellites that have failed so far will simply be left in orbit to gradually descend and burn up in the atmosphere due to atmospheric friction, a process that can take almost a year. year.

A 95% success rate like Starlink’s, while high, isn’t perfect. While the company expects to launch a total of 12,000 Starlink satellites by early 2020, operating at altitudes ranging from 550 to 1,100 kilometers, that would equate to nearly 600 dead satellites left in orbit.

From my perspective, three spacecraft being essentially ‘killed on arrival’ is not something SpaceX should settle for. says Hugh Lewis of the University of Southampton in England, who works on modeling space debris. ” Hopefully there will be more glitches as we are still early in the mission for most spacecraft, and there are still a lot of things that can go wrong. »

It is worth noting that this first batch of Starlink satellites is essentially a test, and that SpaceX will work to improve the satellites’ reliability in the future, based on the results of this first launch. But with so many satellites planned, a considerable number of concerned voices have been raised about the space junk produced by large constellations like this one.

A 5% failure rate is actually better than most constellations in history, especially this size.,” says Brian Weeden of the space advocacy organization Secure World Foundation. “ But this is definitely not good enough for a very large constellation of hundreds or thousands of satellites. The goal should be a maximum failure rate of 1% or less, and even that rate would lead to dozens of dead satellites. »

Many other companies, including OneWeb and Amazon, have their own plans for large constellations of satellites, with the aim of beaming the Internet to Earth to provide global satellite high-speed Internet coverage. If all these constellations came to fruition, they would add about 20,000 satellites in orbit; there are currently only 2,000 active satellites.

The astronomy community also expressed fears, with some astronomers noting that the satellites were brighter than expected and therefore could make nighttime sky vision difficult. In an effort to allay those fears, SpaceX said it was monitoring the satellites’ visibility as they were pushed into their target orbits.

We also contacted leading astronomy groups around the world in advance to discuss the Starlink mission profile, scientifically estimate impacts on astronomy activities, and assess useful mitigation measures for the future.,” added SpaceX, according to Business Insider.

But it is space debris that is the most pressing problem right now, and SpaceX will have to prove it can fix these flaws in its future satellites to reduce the number of dead satellites in orbit. With no onboard backup deorbiting system, unlike others like OneWeb which will install a handle onboard each satellite allowing it to be captured, any faulty Starlink satellite will simply be left in orbit until it re-enters the atmosphere itself. same.

For a spacecraft at 550 kilometers, [un taux d’échec de 5 %] is acceptable, I imagine, Lewis admits. ” But for a large number of machines at 1,000 kilometers, this will not be enough. »

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