Comment by qayxc

1 year ago

> Which also makes me wonder how many of the shooting stars I've seen recently are just old starlinks burning up.

Probably close to none. The lifetime of the satellites is about 5 years give or take. According to this page [1], a total of 355 satellites have deorbited over the past roughly 5 years. That's an average of about 71 per year or about one every 5 days.

Since planned disposals are done over uninhabited areas (e.g. the pacific ocean), the likelihood of spotting one is very low.

Hope that helps answer your question, even it wasn't necessarily meant seriously :)

    [1] https://starlinkinsider.com/starlink-launch-statistics/

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macspoofing  1 year ago

>The lifetime of the satellites is about 5 years give or take. According to this page [1], a total of 355 satellites have deorbited over the past roughly 5 years.

Wow ... is it economical to replace the entire constellation every 5 years? How does the business side work? Or is it just a great money-burning party?

  • try_the_bass  1 year ago

    This is a large part of why they're pushing so hard on Starship. Falcon 9 is great and wildly economical, but it's not enough to make Starlink profitable in the long term. They need Starship to make that happen.

    They also want to make Starlink satellites bigger, which also requires Starship's much larger diameter.

aetherspawn  1 year ago

If someone makes a mistake and the satellite deorbits in the wrong place, am I likely to be impaled by a satellite screw or something travelling at terminal velocity?

  • oconnor663  1 year ago

    No, they burn up. You can think of how much work goes into the heat shields on spacecraft that are supposed to survive reentry. Satellites have none of that.

    • m4rtink  1 year ago

      Starlinks are actually built so that nothing sizeable remains at all after reentry. This even delayed the laser coms a bit, as the original laser mirrors were too sturdy & so pieces of them could theoretically make it through.

    • scottlamb  1 year ago

      I also think a screw at terminal velocity might not be particularly dangerous, similar to the popular "will a penny dropped off the empire skyscraper kill you?" question.

      ...which I suppose is closely related. The deorbiting satellite burns up because all that potential energy goes into heat because of the ~friction~ [edit: compression, thanks for the correction] that limits it to that low terminal velocity.

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  • mlindner  1 year ago

    Actually the person you replied to somewhat incorrectly. They're not targeted re-entries because the on-board propulsion of Starlink is too low to precisely control the re-entry location. However instead the satellites are designed to be intentionally "demisable" meaning that every portion of the satellite should vaporize/turn to char/dust during re-entry.

    Put another way, every kilogram of Starlink spacecraft has as much energy "stored" in it's motion as around 4-5 tons of TNT.

    • qayxc  1 year ago

      > Actually the person you replied to somewhat incorrectly. They're not targeted re-entries because the on-board propulsion of Starlink is too low to precisely control the re-entry location.

      SpaceX says otherwise, see [1]

         SpaceX spokesman James Gleeson, when asked about the 10 satellites, said SpaceX is “performing a controlled de-orbit of several first iteration Starlink satellites,” using onboard propulsion.

      There's a difference between unscheduled deorbiting (as happened to about 40 satellites after a solar storm in February 2022) and a scheduled deorbiting manoeuvre trigged by ground control. Starlink satellites use electric on-board propulsion (Krypton powered Hall thrusters) that doesn't run out as quickly as chemical or cold gas gas thrusters. There's also not much precision needed to avoid major population centres - Earth is pretty big after all.

      [1] https://spacenews.com/spacex-launches-fourth-batch-of-starli...

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