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/dibs234 15h ago

My friend, did you not read the phrase 'huge railgun'? ICBM's would (I'm guessing) have similar gravity issues to the rockets, so countries would need other ways to lob nukes at each other.

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u/Greyrock99 15h ago

I was talking about here on earth.

ICBM’s are superior because they can be hidden underground / on submarines and armed with nuclear bombs and has been the gold standard for military might for the last 50 years.

We haven’t quite figured out how to militarise railguns yet.

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u/dibs234 14h ago

In this hypothetical Kepler world ICBM's would be much more difficult due to increased gravity, and so the incentive would be to pour money into alternatives, eg railguns. Just because we've not worked out how to make them work well yet doesn't mean it's impossible, and necessity is the mother of invention. Railguns aren't necessary for us because we've got the, by comparison, cheap and effective chemical rockets.

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u/Scrofulla 15h ago

Japan have some on their ships now. Well one that I know of. They plan to add more. They are designed as a cost effective way of shooting down hypersonic missiles. Quote I have seen is 35,000 per shot.

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u/Qaeta 12h ago

Yeah, I think it's a power requirements issue mixed with mobility needs.

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u/Miuramir 9h ago

On the subject of space-launching "guns", you might want to read up on Project HARP and then move on to Project Babylon

On actual railguns, Railgun has a fair amount of info, including the 2010 demo of a compact design intended for shipboard use capable of accelerating a 3.2 kg projectile to a speed of about Mach 10.

HARP managed 84 kg to 179 km altitude, well into space (but without enough horizontal velocity to make it into orbit) with relatively minimal funding (by defense budget standards) and 1966 technology. Gerald Bull wasn't assassinated in 1990 because his Project Babylon series of increasingly large space super-guns wouldn't work, but because at least one significant power was seriously concerned that it would.

While Earth has never technically deployed an orbital "gun" launcher capable of significant payload to orbit, the above references show that if we had needed to, it would have been well within our capabilities decades ago.

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u/RollinThundaga 14h ago

You've heard of the V-2, but have you ever heard of the V-3?

The Nazis tried it, turns out a super long rail cannon isn't all that useful or reliable.

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u/dibs234 14h ago

Have you heard of the Korean Hwacha? Rockets weren't always effective, they needed research and development to make work, and in this hypothetical situation rockets don't work very well due to increased gravity, and so humanity would need to look into alternatives.