5:19 am

What’s going to happen when 25+ satellites are burning up in our upper atmosphere EVERY DAY? In a really weird bit of synchronicity, after sending out my message yesterday where I ended saying that the environmental effects of low Earth orbit (LEO) satellites was an entirely separate conversation… I was scrolling through Mastodon and the very first posts I saw were on this topic! 🤔 They pointed to these articles:

• Don’t Fear China’s Falling Rocket—Fear the Future It Foretells
• Falling metal space junk is changing Earth’s upper atmosphere in ways we don’t fully understand

The first is a Scientific American article from July 2022 that points to the concerns around all the rocket stage that fall back to Earth after delivering their satellites and burn up in the upper atmosphere.

But wait, you say… SpaceX has re-usable rockets!

Yes, they do, and that’s both amazing and awesome on so many levels. But that is only for the first stage that lifts the payload into space. The next stage that carries the satellites up to their orbit and deploys them is not reusable.

The second article is from last week on October 24, 2023, and gets to the question that I have – what is the effect of all these satellites burning up in the upper atmosphere?

This was one of the questions we had in 2022 at the Internet Society when we developed a paper about using LEO satellite systems for Internet access. And it’s one that concerns me greatly.

Let’s do a little math.

With the current filings at the International Telecommunications Union (ITU), it is very possible that, if all the providers can get their satellites launched (see yesterday’s piece), within 5 years we could see 40,000 – 90,000 satellites in LEO.

Pretty much all of those will only have a 5-year lifespan before they run out of fuel and need to “de-orbit” and burn up in the upper atmosphere. LEO constellation operators are going to be constantly launching new satellites to replace the ones reaching end-of-life.

For the sake of simplicity, let’s just say there are 50,000 satellites in LEO and at some point the launch cadence may level out so that in any given year 10,000 satellites across all the constellations will be falling out of the sky each year.

10,000 / 365 = roughly 27 satellites re-entering the atmosphere EACH DAY!

Every day… 27 more shooting stars to possibly be seen by someone.

(Just work with me on this, okay… I do realize there is no way it will happen so evenly. The reality is that the de-orbiting will probably be lumpy with some days having many and others just a few or none. But look, it’s before 6:00am and I want to keep this example simple, okay?)

Is this okay? Can our upper atmosphere absorb all this without a problem? Or will this in fact cause other problems?

The second article above points to a research article in the journal PNAS that dives into this:

• Metals from spacecraft reentry in stratospheric aerosol particles

The summary at the top is useful:

Measurements show that about 10% of the aerosol particles in the stratosphere contain aluminum and other metals that originated from the “burn-up” of satellites and rocket stages during reentry. Although direct health or environmental impacts at ground level are unlikely, these measurements have broad implications for the stratosphere and higher altitudes. With many more launches planned in the coming decades, metals from spacecraft reentry could induce changes in the stratospheric aerosol layer.

It’s an interesting read that admittedly went beyond my own understanding (ex. I did not actually know “niobium” and “hafnium” were elements… they sound more like something someone would say in Star Trek!). But in reading through it was intriguing to read about the different metals used in satellites and rockets. It was also fascinating to read about the methods the researchers are using to collect the data.

The “Discussion” section at the end gets into the researchers views on possible effects. They outline several different potential effects on particles in the upper atmosphere.

But the “plain language” summary of what effect this may have on our planet could be summarized as:

WE DON’T KNOW!

Which seems to be a common thread in other articles and research I’ve seen so far.

We’re engaged in a grand experiment that may in fact provide ubiquitous global Internet access and truly connect the unconnected and bring connectivity to everyone… it has amazing potential… but what will be impact to our planet and climate?

If you are looking for a research area, I would say this is a VERY good one to study.

And… if you know of research in this area, please send it to me! I would love to gather more info around all of this.

If this newsletter is about climbing up into the crow’s nest and looking out at the horizon with a spyglass, this topic seems like it could be a pretty big iceberg looming out there – and it would be good to understand more about exactly how big it is, or not.

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On a different note, if you are interested in tracking the whole area of “launch providers” that I talked about in yesterday’s message, I *HIGHLY* recommend the “Rocket Report” From ArsTechnica. It’s one of the newsletters I actually open and read every time I get it. Reporter Eric Berger and his expanding team have great info about all sorts of different kinds of rockets.

• A recent edition of the Rocket Report
• Subscribe to the Rocket Report

Until another day when our dog will inevitably wake me up early again,
Dan

P.S. Wait.. you have just received 3 editions of this newsletter in 3 days! That’s more than I have published in some years! Is this a trend? I don’t know… I’m trying out this whole “write a newsletter after the dog wakes you up at 5:00am instead of doomscrolling on social media” thing. It may work… it may fade away. This may be the last one you see from me for a couple of years. 😀 Or maybe it may change to weekly or monthly. We’ll see. It’s all an experiment. And if this is FAR TOO MUCH EMAIL FROM DAN YORK and you want to unsubscribe, I totally get it. Thanks to all of you who are here reading this!

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Disclaimer

Disclaimer: This newsletter is a personal project I’ve been doing since 2007 or 2008, several years before I joined the Internet Society in 2011. While I may at times mention information or activities from the Internet Society, all viewpoints are my personal opinion and do not represent any formal positions or views of the Internet Society. This is just me, saying some of the things on my mind.