this post was submitted on 13 Oct 2023
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[–] [email protected] 17 points 1 year ago (1 children)

20% of the delta-v is not the same as 20% of the energy or fuel. The early stage when the rocket is the heaviest and down in the thickest atmosphere is by far the most fuel-expensive.

[–] [email protected] 1 points 1 year ago* (last edited 1 year ago) (1 children)

That actually makes it much worse. Kinetic energy is a square law so to reach orbit at 5 times the velocity requires 5x5=25 times the energy they're currently using. And air resistance is also a square law so making it go 5 times faster also results in 25 times the air resistance and 25 times the heating due to it.

Most likely if they did get it going fast enough to make it to orbit, it'd burn up in the lower atmosphere before it even got very far.

[–] starman2112 2 points 1 year ago

They don't need to get 100% of the orbital energy into the object at launch. Scarabic's point is that if it can just offer an alternative for getting through the lower atmosphere, it can save a lot of fuel.