this post was submitted on 15 Mar 2024
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[–] [email protected] 0 points 8 months ago (4 children)

Honest question, that might be answered in the article but I’m a little lazy (also not so great at physics). Is the energy efficiency the same for traditional rockets and a rail gun getting into space? I assume it’s the same amount of energy needed regardless of the method

[–] [email protected] 0 points 8 months ago (1 children)

It needs less energy overall because you don't carry the fuel with you. The vast majority of the energy needed for a rocket launch is used to carry a bit more fuel a bit faster.

So in theory a railgun could send a payload in space for only a fraction of the cost.

The problem on earth is the atmosphere, travelling through the atmosphere at orbital speed will instantly vaporize any object due to friction. In the article they are talking about sending objects at mach 1.6 which is close to 2 000km/h. Orbital speed is around 29 000km/h so they would still be far from reaching orbit.

[–] [email protected] 0 points 8 months ago

travelling through the atmosphere at orbital speed will instantly vaporize any object due to friction

You’re aware that re-entry is possible and is done at speeds around 28,000km/h right?

[–] [email protected] 0 points 8 months ago

A railgun will have vastly greater efficiency. Think of propelling yourself on a skateboard by farting vs using your feet.

[–] [email protected] 0 points 8 months ago

Even if it would be the same in theory (which makes sense to me), there's the matter of not needing so much fuel on board.

Even if we assume the cost of the fuel is equal to the electricity cost (though I imagine rocket fuel is pretty pricey), you're also saving on the cost of the larger fuel tank, and the cost of propelling the full fuel tank.

That's my entirely amateur opinion, anyway. Plus, it's cool as hell, which has got to count for something.

[–] [email protected] 0 points 8 months ago (1 children)

You don't have to carry a huge amount of rocket fuel so I assume that the energy requirement would be less. But this is just a laymens guess.

[–] [email protected] 0 points 8 months ago

Didn’t think of this, very good point. Sounds like it might allow for “better” payloads reaching space (supplies for building or food whatever) without needing to worry about huge fuselages.