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Interestingly, development of rockets has only made a bunch of the things you mention cheaper (to the multiple orders of magnitude), not impossible.

Eg. determining location through radio signal triangulation can tell you a location pretty well, but would require placing a lot of signal stations throughout the world. Eg. remember the time-synchronisation mechanisms for watches through AM signals (including in hand watches).

Similarly, we did build a global communications network by placing expensive undersea cables across the world, but systems like StarLink are much cheaper (once you get to economies of scale for launching satellites).

So, like many things, rockets have accellerated discovery and progress, but are ultimately not the be-all solution: they work in tandem with the rest of science and engineering (including cultural development).

GPS done via land radio systems would be so flakey and expensive it would still likely not be implemented. Easy to jam too. And subject to control by terrestrial authorities.

Putting a dozen satellites in orbit - and out of reach of local authorities - is so much cheaper and more reliable, it’s not just a matter of cost - it’s an entirely different product.

Same with starlink. A big part of its advantage is someone can’t just walk over and cut a cable. And no one needs planning approval to put a cable in.

Line of sight to low orbit is about the only way to accomplish that - maybe some kind of high altitude ballon/plane could (loon?) but they’re so comparatively easy to shoot down that it makes it a very different kind of situation.

It seems like you are looking at it only from one side.

Undersea cables are probably more expensive than satellites today, but we'll still continue to put them in. And nope, someone can't just walk in and cut a cable sitting at 5000m under the surface.

Detecting a StarLink terminal is relatively easy from the ground, and someone can just walk in and demolish it once they locate it.

Basically, all tech has pros and cons.

Of course. But to Russias recent chagrin, blowing up/severing a fixed and very expensive cable (or underwater pipeline) is a generally far easier proposition than tracking down mobile and intermittent sources on the ground.

Still possible. But orders of magnitude harder. Nothing says that starlink ground station needs to stay in one place, after all.

Undersea cables get cut all the time, from shipping to nation states.

Trains don’t make cars obsolete, anymore than cars make trains obsolete. Taking out train tracks is much easier and more effective than taking out all possible roads though.

> Undersea cables are probably more expensive than satellites today, but we'll still continue to put them in. And nope, someone can't just walk in and cut a cable sitting at 5000m under the surface.

The cable has to come out on to the surface somewhere, though.

But barring that, dropping IEDs from a fishing boat, with a time fuse and some weight, isn't hard; the trickier part would be knowing where to drop them so they land near the cable. But there are tricks for that too.

Dragging an anchor seems to work pretty well.

D'oh. Of course!

All too easy to get bit by the curse of overcomplicating things.

You might be surprised to learn that Enhanced LORAN recently became operational around the UK's coast, specifically because satellite-based PNT is so susceptible to interference and jamming.

Not at all. It's only being installed in specific, high value areas within a specific jurisdiction. And mainly as a backup. Notably by a party which doesn't control GPS (albeit a close ally).

LORAN has also been used near airports in developed areas for a long time.

That isn't the 'base case' though.

The US military initially developed and launched GPS because of the reasons I stated, and it is still widely used as a base case for exactly those reasons.

Yeah and to add to this I think people are forgetting why Bell was given a sanctioned monopoly. Because there were just cables everywhere. When people say natural monopolies exist in markets with network effects, that can mean literal networks of cables that will block out the sun. Sure, this stuff will improve too, but I think people are also forgetting about the increased surface area and the increased gravity which makes each of these cables required to be thicker or require more support.

https://history.stackexchange.com/questions/58872/did-they-r...

> Interestingly, development of rockets has only made a bunch of the things you mention cheaper (to the multiple orders of magnitude), not impossible.

With finite time, lifespan and resources, "cheap" is often equivalent to "possible". If you look at the connections between inventions and developments that GP mentioned, it's usually the case that the necessary prerequisites don't involve just knowledge, but something getting cheap enough to be available / worth building.

If something is worthwhile, it gets developed and gradually becomes cheaper.

If you were handed an internal combustion engine car without petrol, it would be extremely expensive to get that fuel for the first time.

That even happened with satellites!

Which actually leads me to thinking that a space-adapted race really doesn't want to bother with planets and their big ass gravity well.

Resource extraction from asteroids or moons is a lot easier than carting it out of a big gravity well. Building stations in zero G rather than having to worry about orbital degradation and the like. Atmospheres get in the way of solar energy collection.

Earth is probably only useful as a vacation destination. Unless of course all those UFO reports are actual physics-defying antigrav drives with little green men.

The nice thing about gravity wells is they naturally concentrate things along density gradients.

The bad thing about gravity wells is they naturally concentrate things along density gradients.

Interesting thought. I think ground-based GPS wouldn't be too difficult though - we already have most of earth covered by GSM/3G/LTE, and with updated towers you could have something as precise, if not more, as GPS. Of course the coverage wouldn't be 100%, and navigating in ocean would be more difficult.

Planes would be replaced by trains and aquaplanes for sure. Our modern fastest trains (TGV, Maglev) are only half as slow as the fastest commercial planes. Also, you might have rocketry on such a planet, just not for orbit, and for things that right now we use jets for.

The biggest issue with be probably no detailed aerial maps, and in later stages - no space mining, so such civilisation would be limited to resources on their own planet.

Also, I'm imagining that such a civilisation would send out more signals into space to encourage someone to come and visit them, and hopefully dropship resources from orbit :D

Imagine two civilisations living like that in symbiosis - one on the orbit, able to drop things to the one that is lower, but being able to extract only information / art / mental labour / energy from below.

Higher gravity -> denser atmosphere -> airships start making more sense? In those conditions, flying could've been actually cheaper and safer, even though slower than what we have on our planet.

If you could get to space with a fusion engine, then why would taking satellites into space on said rocket be any different then it is for us (to build GPS)?

Wouldn't LTA blimps work BETTER in higher gravity for flying?

A limit often ignored for high-gravity balloons is, the pressure gradient inside the balloon reaches a point where it tears it apart. When the atmospheric gradient is compressed to some point, the distance between the bottom of the balloon and the top can create enormous forces on the fabric.

So depending on the gravity we're talking about, blimps are out!

That civilization could have invested in rail transit and tunneling instead. Positioning isn’t so hard on fixed roads, although fixing the, in the first place under oceans could be a problem. They might figure out triangulation using their planet’s magnetic field or something. It’s also completely possible that life isn’t viable at all on non-Earth like planets.

Remember that the gravity is higher. Your mountains are more dense and your oceans have more pressure. You're not living on a world with 14psi. You're not living in a world with the same ground, air, or ocean composition. All these change. So all your drills have to be thicker and harder. All your cables need to be stronger.

All projectiles become much shorter range weapons. Maybe once they've got gunpowder they can finally fight at range, though each shot would require a lot more gunpowder relative to the same shot on earth. Maybe it sort of washes out if you figure the inhabitants are all stronger and more sturdy as a result of the gravity.

Such an effect may even highly discourage ranged combat in the first place. I'm sure you'd still have ballista but bows? Probably crossbows. But there's definitely a butterfly effect for sure.

It feels like we've finally found a reason for the old sci-fi trope of future battles using melee weapons

I'm wondering if siege weapons work at all

Dune has a take on this that the movie doesn't do a great job at explaining. But the shield is made to prevent high velocity projectiles and energy weapons. This way the shield can be hidden and fool enemies because the user is still able to interact with daily objects. Like you can eat while wearing the shield and since you'd have body guards it's much harder to get in and stab someone wearing a shield. The Apple version of Foundation has a similar shield but it is more sensitive. Dune's shield has obviously affected many subsequent works.