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What I think is infuriating that companies and countries can just put up as many satellites up there as they want. If you put dangerous[1][2] garbage in the sk

• mlindner 5y ago
  Firstly, that Kurzgesagt video had numerous errors in it including ridiculously false lines like "3-4 satellites are getting destroyed this way every year." The source for that specific line was a politician, not a scientist. The video is not a legitimate source. Secondly, the Kessler syndrome is believed to already be happening by some, but it's a slow process that occurs over 10s to 100s of years and doesn't result in any of the popular depictions like in Gravity or in Wall-e. The Kessler syndrome also does not happen at altitudes where debris are rapidly removed by the atmosphere, which is where Starlink operates in. So even if you were to spontaneously blow up all the Starlink satellites (not at all realistic), the debris would be largely removed after less than a decade. Thirdly, as mentioned Starlink operates specifically in a region of space that is reasonably rapidly (within the order of a few years) cleared up of any non-functioning satellites or debris. Fourthly, you can't call operational satellites with the ability to actively avoid debris and other satellites "dangerous garbage". You could use that term for cubesats with no on-board propulsion possibly, but not Starlink. > IMHO the risk of putting these things up outweigh any potential benefit for underserved regions. The risk is overstated and it's easy to ignore the benefits if it doesn't improve your own life. > Musk could've also invested in ground-based communications infrastructure. If it was so cheap to improve ground-based communications infrastructure it would have been done already. (And it has been in most areas of many European countries because of the density of their populations, but that's not true everywhere)
  • freemint 5y ago
    > The Kessler syndrome also does not happen at altitudes where debris are rapidly removed by the atmosphere Citation needed. If the are enough satellites any decay rate can become irrelevant. > Secondly, the Kessler syndrome is believed to already be happening by some, but it's a slow process that occurs over 10s to 100s of years and doesn't result in any of the popular depictions like in Gravity or in Wall-e. It's slow right now but the expected growth behavior is worse than exponential (dx/dt ~ x^2 vs dx/dt ~ x) and internationally we have fully failed to stop an (dx/dt ~ x) process in the last year. > Thirdly, as mentioned Starlink operates specifically in a region of space that is reasonably rapidly (within the order of a few years) cleared up of any non-functioning satellites or debris. Space junk by definition is unassisted and uncontrolled. So it's not like you aim to present it that any Kessler syndrome will be over in the same time. > The United States Federal Communications Commission (FCC) requires CubeSats and other picosatellites to be designed to re-enter the atmosphere within 25 years of the end of their useful lifetimes. Without an assistance, it is estimated that a CubeSat may take over 150 years to de-orbit from an 800 km altitude. 800km is well within low earth orbit. > Fourthly, you can't call operational satellites with the ability to actively avoid debris and other satellites "dangerous garbage". You could use that term for cubesats with no on-board propulsion possibly, but not Starlink. It doesn't help if those thrusters are not used by Starlink as they failed to do here: http://www.esa.int/Safety_Security/ESA_spacecraft_dodges_large_constellation http://www.esa.int/Safety_Security/ESA_spacecraft_dodges_lar... Starlink (or OneWeb pick one) might be living in an alternative reality with regards to collision risks as this situation shows https://arstechnica.com/information-technology/2021/04/spacex-says-oneweb-spread-false-story-of-near-miss-satellite-collision/ https://arstechnica.com/information-technology/2021/04/space... (read the update for more details). As there can be no disagreement with in Newtonian or Einsteinian physics whether or not there was a risk of collision.