Unprecedented Starlink Reentries : technology

[–] [email protected] 3 points 2 weeks ago* (last edited 2 weeks ago) (2 children)

I don't think this counts as SpaceX's fault. Y'all need to read up on how low-earth orbits work. Otherwise, we all look like space illiterate Luddites.

Satellites in low-earth orbit (e.g. the International Space Station) still encounter some air resistance. The atmosphere doesn't just end; it technically continues out to the moon, thinning out along the way.

Previous kinds of satellite internet relied on satellites in geostationary orbit, which is far enough away from Earth for air resistance to be a non-issue. Unfortunately, they also suffer from time delay as internet signals travel between it and Earth.

SpaceX's StarLink and China's Qianfan solve this by placing satellite internet in low-Earth-orbit, removing the delay by being physically closer. ^[https://www.youtube.com/watch?v=HJceuj30-Z8] However, you need thousands of low-orbit satellites to provide full internet coverage across the Earth because since each satellite is way closer to Earth, their antennas oversee way less land area.

Since they're closer to Earth, they also experience significant air resistance which slows their orbit and will cause them to eventually fall down and burn up in the lower atmosphere. To prevent this, StarLink satellites have thrusters to re-boost their orbits. Once the fuel for them runs out though, they still have to fall down.

TLDR: This is inevitable. China's internet satellite constellations will have the exact same problem once deployed.

[–] [email protected] 7 points 2 weeks ago* (last edited 2 weeks ago) (1 children)

yes, this by design will fall down. the problem is the they don't care what damage it causes to the environment.

[–] [email protected] 1 points 2 weeks ago* (last edited 2 weeks ago)

No company can control how their satellite falls, except make sure it lands in the general area of the Pacific Ocean. China has the same problem with deorbiting rocket stages.

There are plenty of other things to nail SpaceX on, such as blowing up Starship prototypes near populated areas without safety assessments, but this is not one of them. These Starlink satellites are being deorbited on purpose for retirement using the booster engine, but pointed to push them into the atmosphere. By doing so, SpaceX can make sure leftover debris lands in the Pacific, away from people.

Once the satellites are in low earth orbit, their future deorbiting is inevitable. Any concerns about vaporized satellite metals harming the atmosphere should have been assessed before putting them up there, though I don't think anyone made noise about that issue until now.

[–] [email protected] 1 points 2 weeks ago* (last edited 2 weeks ago)

I found a YouTube link in your comment. Here are links to the same video on alternative frontends that protect your privacy:

[–] [email protected] 24 points 2 weeks ago

Planners have long known this would happen. First generation (Gen1) Starlink satellites are being retired to make way for newer models. “More than 500 of the 4700 Gen1 Starlinks have now reentered,” says McDowell.

When we say capitalism is unsustainable

When Starlinks reenter, they disintegrate before hitting the ground, adding metallic vapors to the atmosphere. A study published in 2023 found evidence of the lingering debris. In February 2023, NASA flew a WB-57 aircraft 60,000 feet over Alaska to collect aerosols. 10% of the particles contained aluminum and other metals from the “burn-up” of satellites.

we really really mean it.

[–] [email protected] 19 points 2 weeks ago

Sounds like this generations ozone layer crisis, except it's been democratised to the whole planet!

[–] [email protected] 16 points 2 weeks ago (1 children)

So, another one of the muskrat's projects turns out to be surprisingly shitty?

[–] [email protected] 11 points 2 weeks ago (3 children)

Planned obsolescence. They're supposed to come down.

[–] [email protected] 0 points 2 weeks ago (1 children)

What is even the point of doing planned obsolescence with satelites of all things? It's not like a smartphone that you want customers to keep buying.

[–] [email protected] 6 points 2 weeks ago (1 children)

I hate Musk and his companies just as much as the next person on here, but in this case it's a physical limitation. Starlink, as well as all the other orbital mesh networks in construction or proposed, all have to deal with these issues or simply not exist (I personally don't think such orbital meshes should exist).

We already have satellite internet using satellites in geostationary orbit. Those can stay up for a long time (they'll function until the satellite hardware fails, then continue to orbit for thousands of years), but they're much more expensive to launch and performance is really bad with regards to latency and bandwidth because they're few and very far away.

Starlink tried something new, which was a low earth orbit positioning for better internet performance, but that means you need lots of satellites since they're so close to the earth, and they come down relatively quickly due to atmospheric drag. Even at the 550km or so where Starlink is orbiting, there is enough atmosphere to create drag that eventually pulls satellites down, unless they have propulsion of their own which adds weight, cost, and complexity. And even then, the satellites will come down once something fails or propulsion fuel runs out.

[–] [email protected] 3 points 2 weeks ago* (last edited 2 weeks ago) (1 children)

Thx @knfrmity for some fellow rocketry knowledge. Just because Elon Musk is a capitalist pig doesn't mean that his company's evilness can transcend the laws of physics.

I do believe these satellite internet constellations in LEO are inevitable. They are a massive force multiplier for the military, and also provide insane soft power via low-cost internet across the globe. China is building their own Qianfan constellation to compete.

[–] [email protected] 1 points 2 weeks ago (1 children)

What is the probability that this nonsense will eventually cause a Kessler syndrome? Or does that only happen in higher orbits with less drag?

[–] [email protected] 2 points 2 weeks ago* (last edited 2 weeks ago)

Kessler syndrome is only a big problem for higher orbits where air drag is miniscule. Low-earth orbit refers to a rather large band of space below an altitude of 2,000 km. Objects at the upper end would be much more problematic than at the lower end, since atmospheric density falls off nearly exponentially with altitude.

SpaceX actually says that StarLink is deployed at 550km, much lower than normal.^[https://spacenews.com/starlink-failures-highlight-space-sustainability-concerns/] While this is to decrease latency, it also means their satellites will naturally fall out of the sky in 5 years without periodic boosting of altitude.

Even if Kessler happened at their altitude, we could all just wait a few years for the trash to fall out of the sky. In fact, the more everything smashes together into tiny pieces in said orbit, the faster the problem would solve itself after since as objects get smaller, their surface area to volume ratio increases, which means drag would affect them more per their mass.

[–] [email protected] 8 points 2 weeks ago

Planned obsolescence, I would say, is a form of shittyness, especially when it seems they've invented a fun new way to wreck the ozone layer while they're at it.

[–] [email protected] 14 points 2 weeks ago

They're supposed to come down AND they don't give it a shit what the damage is

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