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Animation 10k Starlink Satellites

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Re: Animation 10k Starlink Satellites

#41

Post by Thlom »

wongarsu wrote: post #16
user32489318 wrote: post #3

What I found so fascinating about starling is how easy it was for a single country, even a single company in this case, to pollute near-earth space. I understand the mechanics of LEO, and the de-orbit mechanics put in place. But the world-wide impact, unknown side-effects on the upper layers of atmosphere on the re-entry of literally thousands of satellites within fairly short period of time?

It wasn't easy at all. Nobody except SpaceX could have done it at the time. This is the result of SpaceX being able to launch much cheaper than anyone before them, and being able to use these high-cadence launches to both implement and test incremental improvements in their rockets and streamline their reuse of preflown boosters. SpaceX was the only conceivable launch provider for this, and if it had been an external…

I think OP was talking about the political side, not the technical side. How one company with the blessing of a regulatory body in one country could put thousands of satellites in LEO with minimal international coordination/deliberation.

Re: Animation 10k Starlink Satellites

#42

Post by kemotep »

mikkupikku wrote: post #7
user32489318 wrote: post #3

What I found so fascinating about starling is how easy it was for a single country, even a single company in this case, to pollute near-earth space. I understand the mechanics of LEO, and the de-orbit mechanics put in place. But the world-wide impact, unknown side-effects on the upper layers of atmosphere on the re-entry of literally thousands of satellites within fairly short period of time?

On a bad year, there might be a few hundred tons of Starlink satellites reentering the atmosphere. In the same year, there will be something like 5000 tons of meteors reentrying, and if you include space dust that radars don't see, you're looking at a few times more than that. This appeal to scary ignorance to poop on a technology is a cynical reflex. Instead of just saying that a bare number with no context scares y…

A quick search shows that it’s more like 50 tons of meteorites entering the atmosphere per day. Or over 18,000 tons per year.

If Starlink’s are about 2 tons each (the v3’s are going to be much larger) and they each have a roughly 5 year life span and the 10,000 currently are equally spread over that lifespan (so around 2,000 a year need to be replaced) that’s equivalent to around 10 tons per day of Starlink material breaking up in the atmosphere.

With the 1 million SpaceX datacenters Musk talks about and an original projected satellite Starlink swarm size of 40,000, that number balloons to something like 500 tons per day.

So while today it is only a fraction of the total amount of material breaking up in the atmosphere, the idea that multiple companies could have Starlink size satellite swarms with lifespans measured in a few years we start to easily dwarf what meteorites do.

Re: Animation 10k Starlink Satellites

#43

Post by xoa »

user32489318 wrote: post #3

What I found so fascinating about starling is how easy it was for a single country, even a single company in this case, to pollute near-earth space. I understand the mechanics of LEO, and the de-orbit mechanics put in place. But the world-wide impact, unknown side-effects on the upper layers of atmosphere on the re-entry of literally thousands of satellites within fairly short period of time?

The answer to a lot of the pollution problems is probably, and perhaps counter intuitively, "even more mass even cheaper, combined with regulations that are enabled by that". The key identified current concern is very specific to aluminum reentry, not just generic "whatever mass". Around 15000 tons of space dust hits the Earth each year no problem, but the chemical composition is quite different from what present typical satellites produce on reentry.

But in turn the composition of present satellites and the nature of their use/lifespan/safety systems has itself been driven heavily by economics. We don't make satellites out of steel or other safer materials not because they don't work, but because of the cost the extra weight imposes. We haven't put satellites in VLEO not because being lower is bad for communications or imaging (it's the opposite, lower is better) because it'd need more satellites, more fuel per sat, and higher cadence, all increasing cost beyond the historic ROI. But Starship or other future fully reusable methalox designs will give us vastly more mass budget and cadence for the same cost. Some of that could result in more trouble with existing designs made for a low cadence/high $/kg environment, because some externalities that were previously acceptable due to lack of scale stop being so at scale. But the same increased budget also means increased budget to ameliorate that. We can trade some of the gains for materials that burn up harmlessly in the atmosphere, designs for lowering apparent magnitude to the ground, for better self-destruct and end of life systems, more fail-safety, more redundancy in general, etc etc. And if that requires more regularly replacement that too is made easier but order of magnitude or more lower cost.

Some of this may happen naturally just due to self-interest, but other parts like pollution may require thoughtful regulation. But such regulation will be a much easier lift when it's affordable, so it's worth it to try to maintain an appropriately thoughtful mindset on the benefits vs tradeoffs and how to keep the former while reducing the latter.

Re: Animation 10k Starlink Satellites

#44

Post by kardianos »

user32489318 wrote: post #3

What I found so fascinating about starling is how easy it was for a single country, even a single company in this case, to pollute near-earth space. I understand the mechanics of LEO, and the de-orbit mechanics put in place. But the world-wide impact, unknown side-effects on the upper layers of atmosphere on the re-entry of literally thousands of satellites within fairly short period of time?

By pollute, you mean "make awesome and useful", right?

You do value human utility, right?

Re: Animation 10k Starlink Satellites

#45

Post by xoa »

0_____0 wrote: post #33
gosub100 wrote: post #27

Earlier quoted context omitted.

And phased-array antennae. The network would be next to useless if each receiver needed to track the satellite physically.

Beamforming is an old technology though. It's not hard to do, just a pain to do cheaply when you've got a bajillion emitters unless you have custom silicon.

>Beamforming is an old technology though. It's not hard to do

Well, so is satellite launch right? Cost, efficiency, and scaling are hard to do. That's SpaceX's entire raison d'etre. Doing a general public usable all weather maintenance free well designed phased array terminal they can sell for $250 and pump out by the millions is as worthy an achievement as near anything else in the Starlink project. And I'd love if it was more available too even terrestrially, for PtP/PtMP links alignment even motionless is a certain amount of work at long distances. And long range high bandwidth stuff isn't cheap. It'd be pretty cool if you could have units for $250 that you just needed to aim vaguely in the right direction and then it all just worked.

Re: Animation 10k Starlink Satellites

#46

Post by krunck »

mikkupikku wrote: post #30
rob74 wrote: post #29

Earlier quoted context omitted.

So, because the 10,000+ Starlinks launched so far (and the countless future satellites Bezos and others want to launch for their own constellations) are in LEO, nothing bad can happen (it can only good happen)? That is, if you disregard the following quote from the article: > Each re-entry deposits about 30 kg of aluminum oxide into the upper atmosphere--an uncontrolled chemistry experiment on a planetary scale.

The bad that can happen is limited by it being in LEO. If these were MEO sats but 50x fewer (Bezos sats BTW) you wouldn't be whining about it even though the potential debris would last thousands of years instead of less than ten. And appealing to the fear of the unknown is little more than motivated reasoning, the amount of rocks and rock dust entering the atmosphere dwarfs Starlink reentries.

Rock dust ≠ AlO

"Aluminum oxide compounds generated by the entire population of satellites reentering the atmosphere in 2022 are estimated at around 17 metric tons. Reentry scenarios involving mega-constellations point to over 360 metric tons of aluminum oxide compounds per year, which can lead to significant ozone depletion."

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024GL10...

Re: Animation 10k Starlink Satellites

#47

Post by mikkupikku »

Retric wrote: post #39
mikkupikku wrote: post #7

Earlier quoted context omitted.

On a bad year, there might be a few hundred tons of Starlink satellites reentering the atmosphere. In the same year, there will be something like 5000 tons of meteors reentrying, and if you include space dust that radars don't see, you're looking at a few times more than that. This appeal to scary ignorance to poop on a technology is a cynical reflex. Instead of just saying that a bare number with no context scares y…

They are 0.8 ton each and last ~5 years. 10,000 / 5 * 0.8 = 1,600 tons per year at 10k satellites, and their goal of 40k satellites would put it well above the amount of asteroid debris impacting each year. Further asteroids contain very different materials and don’t all impact at the very low angles you see from de-orbiting in satellites. Thus, I don’t think you can presume this is meaningless without actually model…

They last 5 years if they're dead in orbit. These satellites have electric thrusters and boost themselves regularly to maintain orbit, so your estimate is wildly off.

As for presuming them to be safe, there's fuck all evidence to the contrary. Whining with baseless speculations about the effect of satellites burning up is motivated by the base reflex to shit on any technological progress as an environmental disaster in the making, but nobody can come up with a story about how dolphins might choke on satellites so instead we get this "muh aluminum" narrative.

Re: Animation 10k Starlink Satellites

#48

Post by 0_____0 »

xoa wrote: post #45
0_____0 wrote: post #33

Earlier quoted context omitted.

Beamforming is an old technology though. It's not hard to do, just a pain to do cheaply when you've got a bajillion emitters unless you have custom silicon.

> Beamforming is an old technology though. It's not hard to do Well, so is satellite launch right? Cost, efficiency, and scaling are hard to do. That's SpaceX's entire raison d'etre. Doing a general public usable all weather maintenance free well designed phased array terminal they can sell for $250 and pump out by the millions is as worthy an achievement as near anything else in the Starlink project. And I'd love if…

Hardware gets a bit easier in some respects when you have unit scale and don't need to make COGS+margin back on the sale. If Ubiquiti sell a base station, half of the unit price is gross margin. If SpaceX sell a Starlink terminal, they don't even have to cover COGS for it to be a good business case, because they're selling the service not the device.

The Starlink terminal is a very cool piece of kit, but it's not nearly as interesting as what they're hucking into LEO, and how they're doing it.

Re: Animation 10k Starlink Satellites

#49

Post by Retric »

mikkupikku wrote: post #47
Retric wrote: post #39

Earlier quoted context omitted.

They are 0.8 ton each and last ~5 years. 10,000 / 5 * 0.8 = 1,600 tons per year at 10k satellites, and their goal of 40k satellites would put it well above the amount of asteroid debris impacting each year. Further asteroids contain very different materials and don’t all impact at the very low angles you see from de-orbiting in satellites. Thus, I don’t think you can presume this is meaningless without actually model…

They last 5 years if they're dead in orbit. These satellites have electric thrusters and boost themselves regularly to maintain orbit, so your estimate is wildly off. As for presuming them to be safe, there's fuck all evidence to the contrary. Whining with baseless speculations about the effect of satellites burning up is motivated by the base reflex to shit on any technological progress as an environmental disaster…

“A Starlink satellite has a lifespan of approximately five years” https://www.space.com/spacex-starlink-satellites.html

A 5 years useful lifespan sets the replacement rate and thus the average number burning up each year. In steady state the delta between end of life and reentry is irrelevant, instead the average number of satellites launched each year = average number that burn up each year.

As to harm. Aluminum is mildly toxic, you don’t eat your bike but vaporized aluminum from a satellite is way more likely to cause harm than if the things were made of steel. The plastic bits are likely fine though.

Saying let’s study something ahead of time rather than contaminating all the world’s farmland with and then seeing what happens seems like a perfectly reasonable standard. Technology has generally been wonderful, but that doesn’t mean everything is equivalent. We want to phase out leaded aviation fuel in the US even though it’s ‘only’ 2,000 tons of lead per year, that’s still enough to be problematic. Perhaps ramping up to ~5k tons/y of vaporized aluminum worldwide is a complete non issue, but if it’s not insisting on some other material isn’t the same as a ban.

Re: Animation 10k Starlink Satellites

#50

Post by user32489318 »

wongarsu wrote: post #20
user32489318 wrote: post #5

Earlier quoted context omitted.

Imagine a threat actor blowing up one or two of them. Or malfunction leading to collision with a launcher. Or any satellite malfunction and failure to de-orbit in time. Remember MAD, mutual assured distraction? Well we created another one for access to space

> Or any satellite malfunction and failure to de-orbit in time Last year they had one "dead as a doornail" Starlink satellite in space. [1] It's v1.5, so deployed sometime between 2021 and 2023. It should be naturally deorbited from atmospheric drag by now. There was also the other Starlink satellite with a tank rupture last December [2] A low number of dead satellites isn't an issue as the other satellites can steer…

A satellite of that magnitude can have many failure modes, onboard computer will do their best to de-orbit if it encounters unrecoverable failure: it can use thrusters, it can change attitude to increase surface area towards the sun or the atmosphere, rearrange solar panels etc etc. Assisted de-orbit it can be done very quickly. Unassisted de-orbit will take some time. This is a known and solved problem, we have been relying on this for many years. This is what you’re referring to with your links.

What I’m trying to communicate is that if s/c fails in a non-recoverable way, thruster stuck on, pierced propellant tank, adcs failing in a specific way (e.g. you can get unlucky and get particular bit-flipped that pass checksum etc etc), it is theoretically possible to end up in a non-recoverable state. For example: accelerate into an elliptical orbit or due to orbit perturbation catch-up with your neighbors (all of which will need to do orbital maneuvers and waste propellants). This stuff happens. I’m no longer in this field, but my team lost university satellite because of this. Everyone hopes for a nice decay orbit but it can get funky, and very very hard to model.

Lastly, there’re cases where satellites have been destroyed on purpose. Look up Chinese and Russian tests. The debris field produces for this is hard to model, it will propagate and react to solar winds, upper atmosphere disturbances, neighboring objects,.. Small particles pierce through everything. You will not see them, you will not be able to track them.

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