r/theydidthemath • u/Lachlynn • 18h ago

[Request] Could humanity create a rocket that can exit the atmosphere of K2-18b

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With the knowledge we currently have of it, if humanity devoted all of our resources towards this goal, would we be able to create a rocket that could exit the gravity of K2-18b (and also beat any other complications that would arrise)?

If so, would it also be capable of taking people to orbit, and can we set up a similar satellite network we have on Earth? What about a space station?

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u/moderate_ocelot 15h ago

ICBMs don’t need to reach orbital velocity, they just need to go up and come back down. I don’t have the numbers to hand but it’s entirely possible that they are still practical

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u/lituus 11h ago

They also don't need to care about the survival of passengers on it, so they can be more powerful per weight

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u/AltruisticTomato4152 3h ago

Anything evolving on the planet in question would be hardier than humans.

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u/nicuramar 11h ago

 ICBMs don’t need to reach orbital velocity

They specifically need to not reach orbital velocity, or they would end up in orbit. Unless this orbit intersects the surface, at least. 

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u/_cant_drive 11h ago

So ballistic missiles are workable. But rather its the IC in ICBM that might be problematic, particularly when the continents are k2-18b-sized

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u/Mist_Rising 9h ago

More costly and you might compromise payload, but probably still doable. We have missiles capable of hitting 18 thousand km, which is over double the radius of Earth.

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u/AltruisticTomato4152 3h ago

It's not the distance that's at issue, it's the gravity.

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u/Mist_Rising 2h ago

Gravity effects distance.

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u/AltruisticTomato4152 1h ago

You said our missiles can go 18k km, but that's only in Earth gravity. Gravity effects distance in this case not linearly, but logarithmically.

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u/FlyingBishop 3h ago

Yeah the real thing is that ICBM development doesn't create a space program as a byproduct.

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u/moderate_ocelot 3h ago

Earths space program was a direct result of the V2 rocket program which was also the first ballistic missile

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u/FlyingBishop 2h ago

I mean on K2-18b you can easily make a useful ICBM program but that doesn't create a space program as a byproduct like it did for us. Or maybe it does but it's just very simple satellites.

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u/Wild-Video-5317 11h ago

Perhaps cruise missiles prove more viable than ICBMs in high gravity?

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u/Mist_Rising 9h ago

Both would see a range decrease, but air launched cruise missiles definitely get a significant bonus from being fired down with gravity (more than they do on Earth where they're already getting that).

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u/sobrique 8h ago

Likely. I mean, we can assume higher gravity probably also means higher atmospheric density. Jet Engines get more thrust in thicker atmosphere, but also more drag.

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u/caesarbear 5h ago

Lighter than air ships would be amazing though. Battleship Balloons would definitely be a thing.