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One to two Starlink satellites are falling back to Earth each day

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Re: One to two Starlink satellites are falling back to Earth each day

#111

Post by sidewndr46 »

ricardobeat wrote: post #44
nicce wrote: post #31

Earlier quoted context omitted.

There is a limit how much satellites LEO/GEO can hold unless every satellite has perfect dodging system. Called as Kessler syndrome [1], and one estimate is around 70k satellites. So it is a race who can get the most satellites orbiting, because after a certain point, there is no "space" anymore, and anyone who tries to launch after that point, will be blamed for destroying the satellites of the others. Winner takes…

That’s one single estimate, and the problem is much more nuanced. For example, Starlink satellites orbit so low, that even if every single one of them collides and becomes dust, it will all decay and burn up in a matter of months, a couple years at most. The debris cannot physically move to higher orbits to affect other “normal” satellites, though it might impair launches. Conversely, collisions at much higher geosyn…

I don't know the specifics of starlink satellites but a rupture of any pressurized line has a chance of causing an unintended ascent. Thankfully in most cases the satellite is stabilized, so there is a good chance the satellite just gets a huge amount of rotational velocity added to it with no increase in altitude.

Re: One to two Starlink satellites are falling back to Earth each day

#112

Post by MikeNotThePope »

JumpCrisscross wrote: post #94
whazor wrote: post #77

Earlier quoted context omitted.

Yes, it is much better to error on the side of losing satellites, versus making future space travel impossible.

> versus making future space travel impossible Not a real thing. (It was proposed as a possibility. We searched the parameter space. Mostly in the context of militaries trying to figure out how to deny orbits to an adversary. It's really difficult, to the point that even if one were intentionally trying to cause Kessler cascades, they wouldn't deny an adversary access to orbit.)

Although it could become risky enough that the cost mitigation becomes untenable. For example, I wouldn't want to live in a neighborhood so dangerous that I have to pay to cover my house in thick armor plating just to avoid being collateral damage of the violence shenanigans outside my front door.

Re: One to two Starlink satellites are falling back to Earth each day

#113

Post by stronglikedan »

JumpCrisscross wrote: post #101
Fischgericht wrote: post #66

[Disclaimer: Not a hater, just a Nerd looking at data.] And just as Tesla's stock goes up whenever there are reports about them no longer selling cars, or being years behind on self-driving tech and robotics... if Starlink would be publicly traded, their stock would now shoot way up. On a more serious note: If analysts would do their job, they could have found out years ago that Starlink will never ever be profitable…

> "But why are you only assuming a usage time of 3 years?" Your entire analysis rests on this point, which you fail to demonstrate. (You also cite zero sources, which isn't encouraging.) (EDIT: This assumption is conservative, but reasonable.) Was this AI generated? > The cable itself costs virtually nothing Did you attempt to look up the cost of laying new fibre trunk? > due to their Satellites now being massively o…

> Was this AI generated?

It's crazy to me that people use AI to generate comments for social sites of all things, but here we are.

Re: One to two Starlink satellites are falling back to Earth each day

#114

Post by josefritzishere »

josefritzishere wrote: post #29

I am not convinced that Starlink will continue to exist long term. They reported break even in 2023 but I don't think that included the ongoing cost of replacing satillites.

Starlink is not publicly traded. That lowers the bar on transparency so we're all relying on estimates and press releases which are mostly marketing vehicles. Absent rela quarterly financial reports I think most of this is still in the realm of opinion.

Re: One to two Starlink satellites are falling back to Earth each day

#115

Post by wat10000 »

JumpCrisscross wrote: post #2

> Soon, McDowell told us, there will be up to 5 satellite reentries per day Starlink’s next-generation V3s, which will require Starship to launch, weigh in around 2 metric tonnes [1]. (They’re currently “around 260 and 310 kilograms” [2].) “Every day, Earth is bombarded with more than 100 tons [91 metric tons] of dust and sand-sized particles” [3]. So we’re talking about a 2 to 10% increase in burn-up by mass. (Not a…

A 2-10% increase seems like a hell of a lot.

Human CO2 emissions are well under 10% of natural CO2 emissions, and yet that additional amount has been enough to increase the atmospheric concentration of CO2 by over 50% and substantially alter the planetary climate.

CO2 in the atmosphere is at a vastly larger scale than mass falling in from space, so that doesn't mean this is a problem, but that percentage certainly seems to indicate that the question should be studied further.

Re: One to two Starlink satellites are falling back to Earth each day

#116

Post by ogig »

JumpCrisscross wrote: post #2

> Soon, McDowell told us, there will be up to 5 satellite reentries per day Starlink’s next-generation V3s, which will require Starship to launch, weigh in around 2 metric tonnes [1]. (They’re currently “around 260 and 310 kilograms” [2].) “Every day, Earth is bombarded with more than 100 tons [91 metric tons] of dust and sand-sized particles” [3]. So we’re talking about a 2 to 10% increase in burn-up by mass. (Not a…

I hear 10% increase on a global constant and that doesn't sound like peanuts. If we increase 10% each few years that might be a problem? I don't know anything about whatever field studies this but given that LEO constellations born yesterday even that 2% increase in stuff coming from the skyes sounds significant to me.

Re: One to two Starlink satellites are falling back to Earth each day

#118

Post by cowpig »

JumpCrisscross wrote: post #2

> Soon, McDowell told us, there will be up to 5 satellite reentries per day Starlink’s next-generation V3s, which will require Starship to launch, weigh in around 2 metric tonnes [1]. (They’re currently “around 260 and 310 kilograms” [2].) “Every day, Earth is bombarded with more than 100 tons [91 metric tons] of dust and sand-sized particles” [3]. So we’re talking about a 2 to 10% increase in burn-up by mass. (Not a…

Why is a 2-10% increase a small amount? What increase would be too much?

Re: One to two Starlink satellites are falling back to Earth each day

#119

Post by JumpCrisscross »

TheAlchemist wrote: post #103
Fischgericht wrote: post #66

[Disclaimer: Not a hater, just a Nerd looking at data.] And just as Tesla's stock goes up whenever there are reports about them no longer selling cars, or being years behind on self-driving tech and robotics... if Starlink would be publicly traded, their stock would now shoot way up. On a more serious note: If analysts would do their job, they could have found out years ago that Starlink will never ever be profitable…

That's also my opinion - it will probably never be profitable - it's a great product, but the economics are not right - and that's why no other provider did this (even though they have the tech). Let's see what happens once the bubble pops.

> once the bubble pops

What's the bubble? It's cash-flow positive. All of SpaceX is cash-flow positive--they've been buying back their own shares.

You can argue it's overrated, i.e. customers will drop it after trying it for a while. (Or when a recession forces their hand.) But bubble requires leverage and losses, neither of which SpaceX (or Starlink) have.

Re: One to two Starlink satellites are falling back to Earth each day

#120

Post by ggreer »

Veedrac wrote: post #106
ggreer wrote: post #42

Earlier quoted context omitted.

Current Starlink satellites are 800-970kg[1] and 100% of their mass is vaporized on reentry, so 1-2 satellites a day would be approximately 1.5 tons per day added to the atmosphere. The atmosphere's mass is 5.15 quadrillion tons. Even if satellite vapor stayed in the atmosphere forever, it would take approximately 10,000 years before it reached 1 part per billion. So basically it's not worth worrying about. 1. https:…

This is correct from the perspective of direct health hazards, but there are still plausible risks. We know from history you don't need a lot of mass to cause global problems, if the material is catalytic.

If the vaporized satellites were entirely converted into a compound that was as damaging to the ozone layer as the most potent CFC (R-12 [1]), and the compound stayed in the atmosphere forever, it would take 5,000 years to reach current atmospheric concentrations of R-12.[2]

Vaporized satellites really don't seem like a concern.

1. https://en.wikipedia.org/wiki/Dichlorodifluoromethane#Enviro...

2. https://gml.noaa.gov/hats/graphs/graphs.html

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