30 ms·

If you read the article, SpaceX specifically designed the process to avoid orbiting junk.

by bufferoverflow 5y ago

cogman10 5y ago
Yup, spacex stuff is all LEO. Without input it all crashes into the atmosphere in a few years (3 I believe)
- pishpash 5y ago
  And we inhale it all. (Yes, I know it's insignificant; all things start insignificantly.)
  - dymk 5y ago
    Just wait until you learn just how much random space stuff enters Earth’s atmosphere in any 24 hour period
  - jlmorton 5y ago
    When you consider the century-long global effort burning 2-3 billion gallons of oil every day to raise CO2 from 320ppm to 420ppm, you get a sense of the scale involved.
    - Retric 5y ago
      Yea ~0.033% to 0.040% took ~879,000,000,000,000 kg of carbon with the oceans sucking up another 590 Gt, and land taking 528 Gt from 1750 to 2012. We added another 0.004% in the last 10 years.
  - epivosism 5y ago
    this argument is pretty general; you're a priori attempting to prove that "acknowledged insignificant things are actually significant". This feels too strong!
  - profmonocle 5y ago
    About 15,000 tonnes of material enter the Earth's atmosphere each year from meteors. I know the makeup of satellites vs. random meteors isn't exactly the same, but it's probably not concerning in terms of pollution sources, and it's really hard for me to imagine it getting there.
  - version_five 5y ago
    Someone already mentioned burning oil, I'd like to also mention coal which makes oil look very clean by comparison. Coal is a few ppm uranium, arsenic, and other unpleasant metals (this is from memory, but it has lot of impurities). We burned literally billions of tons of it, putting thousands or tons of these metals into the atmosphere in the process. Also, leaded gasoline
- mypalmike 5y ago
  If you read the article, it's not just that they operate at LEO, but the launch process begins at even lower altitudes so that they can quickly deorbit any problem satellites.
- suifbwish 5y ago
  Would spacex be liable if one of their satellites hits your car or house?
  - iam-TJ 5y ago
    If you can build your house, or drive your car, at that altitude I rather think you'd be the one being liable! :D (based on the fact these satellites are designed to burn up completely upon re-entry into Earth's atmosphere and so no 'chunks' reach the surface)
  - labster 5y ago
    If there’s so little atmosphere that a Starlink doesn’t burn up before it hits your car, the ICE engine would have trouble running anyway.
    - dotancohen 5y ago
      How modified would a Tesla Cybertruck need to be to run on the moon?
      - sneak 5y ago
        If I had to guess, probably quite a bit. I doubt the battery cells or the electronics would hold up under hard vacuum. I recall a story posted here that if you put an iPhone in helium it will break the MEMS components inside of it and it will fail to boot, and that's still at 1 atmosphere.
        dotancohen 5y ago
        The battery is already sealed, and 1 atmosphere isn't a lot of pressure to contain. It might even be able to be pressurized to quite a bit less. Regarding the electronics, engineering-wise that's a solved problem. And it would only need the drivetrain and charging electronics. I suppose that a wider track would be useful in 1/3 G, but that is a mod that off-roaders have been doing at home for decades. Ditto ride height and wheel size. I would not be surprised to see a Cybertruck offloading from a Starship someday, maybe even on a private mission after Artemis finishes.
- markwkw 5y ago
  I don’t think this is true. Looking at this: https://i.stack.imgur.com/pMchk.jpg https://i.stack.imgur.com/pMchk.jpg from UN, objects above 500km take ~25 years to decay from orbit. They reportedly start at 550km, so I wonder how they hope to achieve 3 years of deorbit without active control.
  - trothamel 5y ago
    That's wrong. There were four missions that were deployed to apogees above 300 km, but most are deployed to 250km and below. That means that satellites that fail tend to burn up quite quickly, in a few years. Here's a chart of deployment apogee and perigee. https://twitter.com/planet4589/status/1491256299002155012/photo/1 https://twitter.com/planet4589/status/1491256299002155012/ph...
  - teraflop 5y ago
    That infographic is a very simplified view of a complex subject. Here's a more detailed overview: https://www.spaceacademy.net.au/watch/debris/orblife.htm https://www.spaceacademy.net.au/watch/debris/orblife.htm Bear in mind that Starlink is much lighter and "draggier" than typical artificial satellites. Based on publicly available data, I get a ballpark figure of roughly 20 kg/m^2 for the ballistic coefficient of a tumbling Starlink satellite. Just eyeballing the graphs in the link I provided, that corresponds to a lifetime of something like 2-9 years, depending on solar conditions.
  - jccooper 5y ago
    It depends on density and cross section (and solar flux); a 500km orbit can be 2-30 years, depending. That's all basically still in the "self-cleaning" domain. Being rather dense and flat, I'd expect Starlink to be on the lower end of that range. http://www.spaceacademy.net.au/watch/debris/orblife.htm http://www.spaceacademy.net.au/watch/debris/orblife.htm The Starlink "0.9" batch was launched in May 2019. Most reached operational altitude; those that did not decayed quite early, as expected. Those that remained operational have by now been deliberately dropped, but some 5 seem to have become unresponsive at a more-or-less operational altitude. See dashboard at https://forum.nasaspaceflight.com/index.php?topic=49936.200 https://forum.nasaspaceflight.com/index.php?topic=49936.200 Starlink-43 is the first of those to fully decay, reentering around 26 January. https://in-the-sky.org/spacecraft.php?id=44257 https://in-the-sky.org/spacecraft.php?id=44257 Starlink-24 is probably going to be the slowest of that cohort. It might have a couple years left. https://in-the-sky.org/spacecraft.php?id=44257 https://in-the-sky.org/spacecraft.php?id=44257 Natural decay in <5 years is really quite fast as these things go.
YaBomm 5y ago
zakwear 5y ago
There is no guarantee of this. Very possible the satellites can break up and cause junk/collisions. They are too bright and block astronomers already: https://static.independent.co.uk/s3fs-public/thumbnails/image/2020/08/25/16/spacex-starlink.jpg?quality=75&width=1200&auto=webp https://static.independent.co.uk/s3fs-public/thumbnails/imag... https://www.labroots.com/trending/space/22175/spacex-starlink-satellites-astronomical-impact-astronomy-2 https://www.labroots.com/trending/space/22175/spacex-starlin...

If you read the article, SpaceX specifically designed the process to avoid orbiting junk.

cogman10 5y ago

Yup, spacex stuff is all LEO. Without input it all crashes into the atmosphere in a few years (3 I believe)

pishpash 5y ago
And we inhale it all. (Yes, I know it's insignificant; all things start insignificantly.)
- dymk 5y ago
  Just wait until you learn just how much random space stuff enters Earth’s atmosphere in any 24 hour period
- jlmorton 5y ago
  When you consider the century-long global effort burning 2-3 billion gallons of oil every day to raise CO2 from 320ppm to 420ppm, you get a sense of the scale involved.
  - Retric 5y ago
    Yea ~0.033% to 0.040% took ~879,000,000,000,000 kg of carbon with the oceans sucking up another 590 Gt, and land taking 528 Gt from 1750 to 2012. We added another 0.004% in the last 10 years.
- epivosism 5y ago
  this argument is pretty general; you're a priori attempting to prove that "acknowledged insignificant things are actually significant". This feels too strong!
- profmonocle 5y ago
  About 15,000 tonnes of material enter the Earth's atmosphere each year from meteors. I know the makeup of satellites vs. random meteors isn't exactly the same, but it's probably not concerning in terms of pollution sources, and it's really hard for me to imagine it getting there.
- version_five 5y ago
  Someone already mentioned burning oil, I'd like to also mention coal which makes oil look very clean by comparison. Coal is a few ppm uranium, arsenic, and other unpleasant metals (this is from memory, but it has lot of impurities). We burned literally billions of tons of it, putting thousands or tons of these metals into the atmosphere in the process. Also, leaded gasoline
mypalmike 5y ago
If you read the article, it's not just that they operate at LEO, but the launch process begins at even lower altitudes so that they can quickly deorbit any problem satellites.
suifbwish 5y ago
Would spacex be liable if one of their satellites hits your car or house?
- iam-TJ 5y ago
  If you can build your house, or drive your car, at that altitude I rather think you'd be the one being liable! :D (based on the fact these satellites are designed to burn up completely upon re-entry into Earth's atmosphere and so no 'chunks' reach the surface)
- labster 5y ago
  If there’s so little atmosphere that a Starlink doesn’t burn up before it hits your car, the ICE engine would have trouble running anyway.
  - dotancohen 5y ago
    How modified would a Tesla Cybertruck need to be to run on the moon?
    - sneak 5y ago
      If I had to guess, probably quite a bit. I doubt the battery cells or the electronics would hold up under hard vacuum. I recall a story posted here that if you put an iPhone in helium it will break the MEMS components inside of it and it will fail to boot, and that's still at 1 atmosphere.
      - dotancohen 5y ago
        The battery is already sealed, and 1 atmosphere isn't a lot of pressure to contain. It might even be able to be pressurized to quite a bit less. Regarding the electronics, engineering-wise that's a solved problem. And it would only need the drivetrain and charging electronics. I suppose that a wider track would be useful in 1/3 G, but that is a mod that off-roaders have been doing at home for decades. Ditto ride height and wheel size. I would not be surprised to see a Cybertruck offloading from a Starship someday, maybe even on a private mission after Artemis finishes.
markwkw 5y ago
I don’t think this is true. Looking at this: https://i.stack.imgur.com/pMchk.jpg https://i.stack.imgur.com/pMchk.jpg from UN, objects above 500km take ~25 years to decay from orbit. They reportedly start at 550km, so I wonder how they hope to achieve 3 years of deorbit without active control.
- trothamel 5y ago
  That's wrong. There were four missions that were deployed to apogees above 300 km, but most are deployed to 250km and below. That means that satellites that fail tend to burn up quite quickly, in a few years. Here's a chart of deployment apogee and perigee. https://twitter.com/planet4589/status/1491256299002155012/photo/1 https://twitter.com/planet4589/status/1491256299002155012/ph...
- teraflop 5y ago
  That infographic is a very simplified view of a complex subject. Here's a more detailed overview: https://www.spaceacademy.net.au/watch/debris/orblife.htm https://www.spaceacademy.net.au/watch/debris/orblife.htm Bear in mind that Starlink is much lighter and "draggier" than typical artificial satellites. Based on publicly available data, I get a ballpark figure of roughly 20 kg/m^2 for the ballistic coefficient of a tumbling Starlink satellite. Just eyeballing the graphs in the link I provided, that corresponds to a lifetime of something like 2-9 years, depending on solar conditions.
- jccooper 5y ago
  It depends on density and cross section (and solar flux); a 500km orbit can be 2-30 years, depending. That's all basically still in the "self-cleaning" domain. Being rather dense and flat, I'd expect Starlink to be on the lower end of that range. http://www.spaceacademy.net.au/watch/debris/orblife.htm http://www.spaceacademy.net.au/watch/debris/orblife.htm The Starlink "0.9" batch was launched in May 2019. Most reached operational altitude; those that did not decayed quite early, as expected. Those that remained operational have by now been deliberately dropped, but some 5 seem to have become unresponsive at a more-or-less operational altitude. See dashboard at https://forum.nasaspaceflight.com/index.php?topic=49936.200 https://forum.nasaspaceflight.com/index.php?topic=49936.200 Starlink-43 is the first of those to fully decay, reentering around 26 January. https://in-the-sky.org/spacecraft.php?id=44257 https://in-the-sky.org/spacecraft.php?id=44257 Starlink-24 is probably going to be the slowest of that cohort. It might have a couple years left. https://in-the-sky.org/spacecraft.php?id=44257 https://in-the-sky.org/spacecraft.php?id=44257 Natural decay in <5 years is really quite fast as these things go.

YaBomm 5y ago

zakwear 5y ago

There is no guarantee of this. Very possible the satellites can break up and cause junk/collisions. They are too bright and block astronomers already: https://static.independent.co.uk/s3fs-public/thumbnails/image/2020/08/25/16/spacex-starlink.jpg?quality=75&width=1200&auto=webp https://static.independent.co.uk/s3fs-public/thumbnails/imag... https://www.labroots.com/trending/space/22175/spacex-starlink-satellites-astronomical-impact-astronomy-2 https://www.labroots.com/trending/space/22175/spacex-starlin...