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Comment by didericis | Hacker News Reader

One thing that makes me less scared about Kessler Syndrome than other environmental problems is that there’s a very strong and immediate economic incentive to clean things up and prevent things from getting dirty by the people at risk of making things dirty. If you can’t do maintenance on or launch satellites, that destroys the industry’s source of income.

The consequences for pollution from other industries is usually longer term and less dramatic/direct on the business itself, if it even effects the core business directly.

I think all the effort put into monitoring space debris and the amount of attention things like starlink is getting speaks to this.

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Starlink isn't at the top of my list for "likely Kessler Syndrome starters" because its a rather low orbit.

They're at 550km up. From https://www.spaceacademy.net.au/watch/debris/orblife.htm puts it at likely a 10 year lifespan with some variation. The published lifespan of a satellite is 5 years.

Its the stuff in the 700km to 900km range that's a problem.

http://stuffin.space

https://www.satview.org/spacejunk.php - and you'll see things like STARLINK-1204 already getting deorbtied ( https://www.n2yo.com/satellite/?s=45203 - note its perigee is 204.0 km - its already well below the other orbits)

https://in-the-sky.org/spacecraft.php?id=45203 for more on that satellite.

Starlink-61 appears to be one of the oldest ones still in orbit - https://in-the-sky.org/spacecraft.php?id=44249 though its on its way down and you can see the type of impact and the duration of the "ok, this is going down".

Even with the maximum starlink, that's 1,700 satellites that will last about 10 years.

The 2007 China anti-satellite test created approximately 150,000 debris at 865km. Those are in an orbit that is on the order of 500 years.

Starlink isn't going to be the cause of Kessler Syndrome.

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In hunting this up, I also found https://planet4589.org/astro/starsim/index.html which is relevant to the main topic - the impact on astronomy.

550km is also just the operational altitude. SpaceX initially releases satellites in a much lower initial orbit. If they fail to POST, they fall into the atmosphere months after launch. Starlink climbs slowly to 550km with the same ion thrusters used for station keeping. SpaceX does not want dead birds in their orbital shell.

Looking more closely at https://in-the-sky.org/spacecraft.php?id=45203 - that makes sense. Its released right about 350 km in a rather eccentric orbit which is then stabilized at just under 400, then after about a month there, it climbs to its target orbit over the course of a month up at 550km.

A more natural one is https://in-the-sky.org/spacecraft.php?id=45229 which has the same initial orbit pattern.

The key thing with this is that without anything else, the satellite has a lifespan that is measured in months to years and up to a decade... not centuries. A Kessler syndrome at 550km would certainly be rather up there on the "suck" scale, but wouldn't keep humanity grounded for more than a decade.

One of the important things to remember about debris at a given altitude, without additional energy, an object cannot climb further out of the the gravity well into a higher orbit. It will always come back to the same spot in its orbit one orbital period later.

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