Prof. Sam Lawler
Had a meeting with a bunch of astronomers concerned about satellite pollution. One of them asked the question "what do we think the situation in orbit will be like in 10 years?" which followed on the heels of several people who work with gov't talking about how incredibly pro-commercialization everything is.
It completely devastated me. Apparently I am not very optimistic about how things are going in orbit. I feel better after a long walk in the woods. But still very sad.
Prof. Sam Lawler
@KimSJ @justafrog @mikeolson @floatybirb Their planned satellite lifetimes are 5 years, they're planning to burn up the whole freaking fleet of them and send up new ones (adding tons of metals to the upper atmosphere every day). And with each launch they add uncontrolled debris, and orbit gets denser.
Deorbit times at 550km are something like decades (depending on how circular orbits are).
Further reading: https://arxiv.org/pdf/2204.10025.pdf (check out Fig 6 in particular for debris/collisions)
Kim Spence-Jones 🇬🇧😷
@justafrog @mikeolson @floatybirb @sundogplanets I’m starting to think that commercial interests are going to go on ignoring the risks until they trigger the Kessler syndrome. Nobody seems capable of stopping them. Maybe that’s the way it has to be… wait a decade or two for the debris to decay then start again more sensibly.
Never mind, the CEOs will have had their bonuses by the time it all goes pear-shaped.
JustAFrog
@mikeolson @floatybirb @sundogplanets Wouldn't the trajectory of collision debris deviate a lot from the initial trajectory?
Mike Olson
@floatybirb @sundogplanets Gravity pulls on the small bits just as hard as the big bits, so modulo initial trajectory everything should be coming down at the same speed. Debris should clear as fast as the satellites do.
I take the insider at face value. They know more about planned lifetime than I do. I trust them to have told me the truth as they understand it, and they're pretty technical.
If it's "years" instead of "decades" that seems less bad to me.
Floaty Birb
@mikeolson @sundogplanets Wouldn't it take a while for atmospheric drag to clear up all those satellites and debris though? I thought that was a thing that takes years or decades, depending on the orbit.
Mike Olson
@sundogplanets I raised the question of orbital crowding and collision debris with a Starlink employee recently. I'm concerned about much, but that issue in particular seems like a big one.
The response: Life of individual satellites is single-digit years. They're still subject to atmospheric drag and orbits will decay. They'll reenter, burn up. Same is true for any debris due to collisions. Sort of "self-cleaning."
Do you buy that argument? Pointers to more reading I should do?
JustAFrog
@sundogplanets @KimSJ @mikeolson @floatybirb
The streaked astronomy images in that report make me sad.
It feels a lot like a defaced hiking trail.
Prof. Sam Lawler
@libroraptor @mikeolson they are absolutely not thinking about the consequences of adding so much metal to the atmosphere. It doesn't magically disappear. Outer space isn't legally considered an environment so they don't have to do any environmental assessment work. They're already detecting dust from satellites/rockets in the stratosphere, and it's going to get much, much worse: https://www.pnas.org/doi/full/10.1073/pnas.2313374120
Alistair K
@mikeolson @sundogplanets I don't know anything about this but I do have a question – does "burn up" mean that the stuff is removed without a trace? Or are they thinking only about collisions while dodging engagement with other consequences of atmospheric pollution?
Alistair K
@sundogplanets @mikeolson I wish that we could get the heritage people to take this seriously – occasionally they manage to raise a minor ruckus to get something done but I fear that there are not very many at all who care about our sky heritage. The few who do care are vastly outnumbered by people who want to collect all the broken bottles and chipped ceramics under old houses that aren't even all that old. (I say that as a heritage person!)
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