Earth's atmosphere is shrinking and thinning, which is bad news for Starlink and other LEO Sats
- Reference: 1741674430
- News link: https://www.theregister.co.uk/2025/03/11/greenhouse_gases_reduce_satellite_capacity_paper/
- Source link:
That miserable set of predictions appeared on Monday in a Nature Sustainability [1]paper titled "Greenhouse gases reduce the satellite carrying capacity of low Earth orbit."
Penned by two boffins from MIT, and another from the University of Birmingham, the paper opens with the observation: "Anthropogenic contributions of greenhouse gases in Earth's atmosphere have been observed to cause cooling and contraction in the thermosphere."
[2]
The thermosphere extends from about 90 km to 500 km above Earth's surface. While conditions in the thermosphere are hellish, it's not a hard vacuum. NASA [3]describes it as home to "very low density of molecules" compared to the exosphere's "extremely low density."
[4]
[5]
Among the molecules found in the thermosphere is carbon dioxide (CO 2 ), which conducts heat from lower down in the atmosphere then radiates it outward.
"Thus, increasing concentrations of CO 2 inevitably leads to cooling in the upper atmosphere. A consequence of cooling is a contraction of the global thermosphere, leading to reductions in mass density at constant altitude over time."
[6]
That's unwelcome because the very low density of matter in the thermosphere is still enough to create drag on craft in low Earth orbit – enough that the International Space Station requires regular boosts to stay in orbit.
It's also enough drag to gradually slow space junk, causing it to descend into denser parts of the atmosphere where it vaporizes. A less dense thermosphere, the authors warn, means more space junk orbiting for longer and the possibility of Kessler syndrome instability – space junk bumping into space junk and breaking it up into smaller pieces until there's so much space junk some orbits become too dangerous to host satellites.
Which is bad because we're using low Earth orbit a lot these days for things like broadband satellites.
[7]Here's the ugliest global-warming chart you'll ever need to see
[8]Our world faces 'unprecedented' spike in electricity demand
[9]Humans brought the heat. Earth says we pay the price
[10]Microsoft accused of 'greenwashing' as AI used in fossil fuel exploration
The paper warns we may need to revisit such plans soon.
"Modelled CO 2 emissions scenarios from years 2000-2100 indicate a potential 50-66 percent reduction in satellite carrying capacity between the altitudes of 200 and 1,000 km."
[11]
The good news is the paper notes that satellite makers know Kessler syndrome instability is a possibility, so often build collision avoidance capabilities that let them avoid debris.
The authors hope manufacturers and operators work together on many debris-reduction tactics, and that greenhouse gas emissions are reduced to keep the thermosphere in fine trim. ®
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[1] https://www.nature.com/articles/s41893-025-01512-0
[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2Z9AX1yqfLBQIO550D__u9AAAAQk&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[3] https://science.nasa.gov/earth/earth-atmosphere/earths-atmosphere-a-multi-layered-cake/
[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44Z9AX1yqfLBQIO550D__u9AAAAQk&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
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[7] https://www.theregister.com/2025/02/23/ugliest_global_warming_chart/
[8] https://www.theregister.com/2025/02/14/iea_global_electricity_demand/
[9] https://www.theregister.com/2025/02/02/heatwaves_future/
[10] https://www.theregister.com/2024/10/31/microsoft_greenwashing_ai/
[11] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33Z9AX1yqfLBQIO550D__u9AAAAQk&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[12] https://whitepapers.theregister.com/
Re: Middle age bloat
If you bothered to read this article and the one you linked to, you'd realise that they are referring to different parts of the atmosphere. However, even that wouldn't change your mind about the cause of global heating because, once you go down the conspiracy rabbit hole, there's no getting back out.
Re: Middle age bloat
Using insults is counterproductive and implies you have no strong case for your point of view.
During the Medieval warm period which some claim only affected the Northern Hemisphere the Antarctica penguins thrived due to warmer weather which indicates there was increased warmth in the Southern Hemisphere as well during the Medieval warm period all without an increase in C02.
Google "Historical population changes of Adélie penguins in the Ross Sea region", read the paper & then reason why CO2 is the main driver & possibly what caused the Medieval warm period.
Re: Middle age bloat
>> Burning these fuels, generates tons of extra CO2, which makes the heat-trapping blanket thicker and thicker, warming the planet.
"Blanket thicker" - this is also what we call an "analogy". "If the atmosphere was a blanket, that blanket is now thicker". There may - or may not - be a literal "thickening", or at least an increase in density[1] but that article is very much an introduction for the non-scientific (well, more for the not-yet-scientific-but-we-want-to-get-you-started).
Just in case anyone wants to try "you can't say on this page the atmosphere is getting warmer but then say here it is getting colder" I'll point you to the conspiracy that mass air movements are obviously not caused by localised pressure changes, that is just the story put about by Big Wind.
[1] 'cos CO2 biggerer than just O2! Duh!
Starlink?
I heard a completely unsubstantiated rumour recently that Musk's Skynet grid has been losing satellites.
Could this be the cause?
Re: Starlink?
That probably was just Musk's justification for getting even more subsidies.
Re: Starlink?
No, Elon says Ukrainians have been shooting them down...
Re: Starlink?
It depends on what you mean by 'losing satellites'. Starlink is occasionally "losing" satellites all the time, because these sats simply stop working as a result of particle impact or radiation. And that is in turn because these sats are designed to be relatively cheap, as well as easily discardable and replacable, rather than super-robust but super-expensive. This is how the sats and the network they form are designed.
If you mean "losing satellites" in terms of these sats falling out of orbit and plummeting down in flames... No. That's not happening right now.
Adjust the orbit
If the atmosphere contracts as this suggests, does this not then open up a slightly lower orbit with a molecular density similar to the current environment we use for these satellite constellations?
Somewhere between the Caribbean Sea and the Sea of Tranquillity there must be a region with any given density.
Re: Adjust the orbit
If the atmosphere contracts as this suggests, does this not then open up a slightly lower orbit with a molecular density similar to the current environment we use for these satellite constellations?
Yep. It's one of those good news, bad news things-
The inset figure shows that millions of satellites may operate in the lowest altitude shells while avoiding Kessler syndrome instability. Debris from collisions is removed almost immediately at these low altitudes, so collisions can happen at a very high rate and the environment will remain stable. However, few operators would choose to place their satellites in such a region under those circumstances, so the operational requirements probably become the active constraint in the lower shells.
The SSP cases show that in addition to the cyclic variability in IKC that comes with the solar cycle, secular reductions in mass density from thermosphere contraction have a real impact on the overall capacity of this region. By 2100, considering SSP5–8.5 as the worst-case scenario, a 50% reduction in capacity is observed at solar maximum with a 66% reduction at solar minimum.
Lower density means less drag, so satellites might last longer. Downside is debris in orbit may also last longer, increasing the risk of collisions and Kessler syndrome. It's an interesting attempt to calculate carrying capacity at low orbits, but the 'safe' capacity is still high, ie 'millions of satellites'. But the paper also focuses on variability within the regular 11yr solar cycle, not what might happen during a Grand Solar Minimum, which we might be approaching.
An increase in space junk...
Straker believes the aliens could use space junk to crack our defences.
Middle age bloat
Others insist that CO2 continues to make the atmosphere thicker - https://www.exploratorium.edu/climate/atmosphere#:~:text=Making%20the%20Blanket%20Thicker,and%20thicker%2C%20warming%20the%20planet.