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Starlink satellites are designed to not cause this problem, and are on a low enough orbit that the problem would solve itself naturally in a few years anyway.
by Seb-C 3y ago
Starlink satellites are designed to not cause this problem, and are on a low enough orbit that the problem would solve itself naturally in a few years anyway.
- worldsayshi 3y agoHow do you design them to not cause that problem? Except for choosing an orbit that degrades relatively quickly.
- beAbU 3y agoBy choosing an orbit that degrades quickly. And possibly making the sattelites disposable.
- deleted 3y ago[deleted]
- Tuna-Fish 3y ago> Except for choosing an orbit that degrades relatively quickly. You answered your own question. More specifically, a Kessler syndrome is the problem that occurs when satellites collide and shatter into clouds of sand-sized particles, and then the sand-sized particles impact more satellites and shatter them, leading to a cascade that clears the whole orbit. Because small things deorbit faster than large things (square-cube scaling), this simply cannot happen at orbits that are low enough, at the Starlink deployment orbits if there was a catastrophic collision, most of the material would be out of orbit in a matter of days. At the even lower orbits of V2 constellation, most of the material will be out of orbit in a matter of hours. The reason Kessler syndrome gets mentioned with Starlink is that the original system design had the early sats at 1100km and most of the constellation at ~800km. This would have been really bad, because that's about the worst possible orbit for collisions, as it's just high enough not to be swept clean by the atmosphere, but low enough that orbital velocities are very high and collisions are more likely. After the concerns were raised, SpaceX modified their design to be not dangerous.
- bryanlarsen 3y agoTo augment: sand-sized particles have a massive area/mass ratio, which is the main determinant in how quickly things deorbit. An unpowered Starlink satellite will deorbit naturally in 5 years. A sand sized particle in a Starlink orbit will deorbit naturally within a single orbit (90 minutes).
- bryanlarsen 3y agoAnd more augmentation: sand size particles aren't the concern anyways. Satellites get hit by sand size meteors regularly. The space station is protected by Whipple shields. Satellites aren't, so sometimes they are partially or fully disabled by a sand size particle, but they never disintegrate because of one. Particles under 1cm in size don't cause Kessler because they're too small. Particles over 1cm in size don't cause Kessler because they are big enough to be tracked and actively avoided.
- Seb-C 3y agoThe satellites are equipped so that they can not only correct their orbit themselves, but also deorbit whenever SpaceX decides that it is their end of life, rather than just be abandoned.
- worldsayshi 3y agoThanks for actually answering my question. :) Everyone else is busy telling me I already answered it myself but you added the information I was asking for. :/
- local_crmdgeon 3y agoBy choosing an orbit that degrades relatively quickly.
- exitb 3y agoYes, they're designed not to cause the problem, but wouldn't they feed the problem, if it's ever caused by someone else?
- beAbU 3y agoHow? If they're in a low orbit how can they get higher to pose a threat? If they collide with something that is en route to a higher orbit, then the collision takes place in this low orbit, and any debris will also be in that low orbit?
- exitb 3y agoThey're operating around 500 km, which is not the lowest of orbits. There's stuff below, including people in the orbit.
- doikor 3y agoAs long as the satellites are under 600km or so they will deorbit on their own in under 5 years. So in the worst case scenario caused by Starlink we would not be able to access space for 5 years which while not great is not the end of the world either. The time to deorbit is not linear. So this 500km orbit is fine while 700km orbit would get us ~25 year deorbit time. 800km over 80 years and so on.
- Heliosmaster 3y agogenerally when two satellites collide some debris can be shot at a higher orbit which will take forever (or will not) reenter atmosphere. See the scatterplot of debris for the Chinese collision test of 2000: https://en.wikipedia.org/wiki/Space_debris#/media/File:Gabbard_diagram.png https://en.wikipedia.org/wiki/Space_debris#/media/File:Gabba... See this video for evolution of debris and altitude over time: https://www.youtube.com/watch?v=mQT5aMa_7iI https://www.youtube.com/watch?v=mQT5aMa_7iI
- doikor 3y agoThe Chinese test also happened around 350km higher then Starlink satellites (850km). The natural deorbit time at that altitude is already over 100 years vs under 5 years at 500km. Also it was literally the worst possible collision being an intentional head on collision. Satellites accidentally hitting each other on orbit are very unlikely to hit each other head on as it is very uneconomical to put satellites in a reverse orbit that low (there is a reason why we do rocket launches towards east if possible)
- jksk61 3y agowhat a laughable sentence, there have been at least 2 near misses last year between starlink satellites and Tiangong. Also, if there's a collision, the smaller parts and debris would remain in orbit far longer than expected (hence causing more incidents).
- Dig1t 3y agoIt is not laughable, Starlink satellites are in a low enough orbit that they will automatically deorbit due to air drag. They will not contribute to Kessler Syndrome. >SpaceX said that a large part of Starlink satellites are launched at a lower altitude of 550 km (340 mi) to achieve lower latency (versus 1,150 km (710 mi) as originally planned), and failed satellites or debris are thus expected to deorbit within five years even without propulsion, due to atmospheric drag. https://en.wikipedia.org/wiki/Kessler_syndrome https://en.wikipedia.org/wiki/Kessler_syndrome