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Comment by nradov | Hacker News Reader

That is not feasible at a cost any current nation state could afford. Due to the inverse square law, the power output requirements to achieve any noticeable jamming from geostationary orbit would be enormous. There have been limited tests of fission reactors in space but they are too complex to operate reliably unattended for long. So, satellites are going to limited to solar or RTG power.

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Only if using old school ‘blanket the area’ monopole antennas or if the goal was to cover the entire potential area all at once -but that seems unlikely to be desirable most of the time.

Phased arrays and beam steering would allow them to pick and choose the area at will with high resolution - or even specific targets like several hundred airliners at once.

Notably, the same things that starlink needs for being able to properly track base stations and communicate at the timescale/numbers it needs, and the tech is widely used in everything from cell phone towers to military.

Starlink has it a lot easier due to LEO, but they’re also a private company with a much harder problem and on a shoestring budget compared to a nation state.

TDP would be a lot lower if they could get it focused well enough. And it wouldn’t need to be operating all the time - a ‘war’ mode vs sleep mode seems like it would work too.

When not jamming, it could be a passive signals intelligence platform.

Or build a couple dozen and put in a lower orbit. Not like it would make a dent in China or Russias military budget, or require any tech newer than 20 years old for them.

Given the wavelengths and distances involved there are severe physics limits to how much beams can be steered and focused. These aren't lasers. What you are proposing isn't practical at a cost any nation state can currently afford.

You seem really invested in ‘no one could afford it’, even at lower orbits.

Which seems pretty hilarious considering how much is getting spent on all this tech, and how much of an arms race it clearly is.

Especially considering how TS programs in general are usually a decade or two ahead tech wise anyway.

[https://www.defenseone.com/threats/2022/04/dia-warns-chinas-...]

If you think there aren’t surprises hiding in the Chinese or Russian’s pockets on this front, you’re far more optimistic than I.

Maybe they’ll just shoot down all the GPS satellites though.

> there are severe physics limits to how much beams can be steered and focused.

Are you skimming over this part? Of course enemy nation states have invested in jamming capability... just not on this front

And are you skimming over the part where I said lower orbit would still be cheap?

While not responding to my other comments?

> Or build a couple dozen and put in a lower orbit. Not like it would make a dent in China or Russias military budget, or require any tech newer than 20 years old for them.

Look at this animation[1] for a moment (click the >> or >>> button to speed up) and think about what it would actually take to get "in front" of enough satellites to block out a given geographic region; even just a single city. There are hundreds of satellites in each orbital plane, rapidly cycling through and taking each others' place.

You obviously cannot have counter-satellites in a geosynchronous "position", and you also can't have satellites simply move between greatly different orbits (or phases of existing orbits) willy nilly; The delta-V requirements are just too great. This just isn't a feasible strategy.

[1] https://heavens-above.com/Starlink.aspx

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