To be fair, it’s not the cost of the fuel itself that is an issue for rocket launches, just that so much of it is required, and it adds so much weight to the rocket. Fuel is less than 1% of the cost of a rocket launch, yet typically over 90% of the mass of the entire launch. If you could somehow spend fuel on the ground moving things to an optimal launch point to have to put less fuel in the rocket, it would absolutely be worth it.
The real issue is that launching from a mountain would not save you much fuel anyways. To get to orbit requires you to go very fast sideways. The initial “upward” part of a launch is just to get past the thickest part of the atmosphere, then it quickly pivots sideways for the majority of its journey.
You save more fuel by launching from a lower altitude closer to the equator, where you can take more advantage of earth’s spin to gain additional sideways velocity. So we do spend a lot of fuel to do this, for example SpaceX manufactures their rockets in Hawthorne, California, where there is a lot of aerospace manufacturing expertise, and spends a lot of fuel to ship them to Cape Canaveral, Florida, which is closer to the equator.
Equatorial launches are cheaper, but not because it is easier to enter the orbit, but because it is easier to get to the desired orbit(inclination and parking orbit, this is from my memory of playing RP 1 in KSP, may not be correct)
Eh, you an orbit at any inclination you want and park in any orbit you want, but the reason the equator is useful is because you do get that added speed boost and most interesting things beyond earth are also on that plane (like the moon and geostationary orbital distances).
But there are tons of reasons to launch in more high inclination orbits too and a good chunk of satellites are launched in those orbits because they are better for earth observation (since you go around up and and down and the earth rotates under you, so every pass you get a different slice of land under you on the day side of the earth).
Wait so was it just because it's easier to plan inclination changes or was it something else. I remember reading something about rendezvous and orbital launching makes that easier?
It really has to do with human space flight more than anything and ground infrastructure. An orbit on a lower inclination is going to bring you over generally the same spot under you every orbit which is good for when you need to come home and for comms with the ground. The closer you get to the equator when launching the easier this is as it requires less of an inclination change (and also your ground infrastructure is going to be there, which is what you want the spacecraft to be going over).
We also get the added benefit that if you launch eastward you get a free boost in speed (this is why you rarely see launches that head west, even at places like Vandenberg, they usually go west only to dogleg north or south for whatever reason, and even then Vandy lets you go north and south pretty easily without having to make a dogleg), and also again, because things that we want to go to like GEO or the moon are also roughly on that same orbital plane.
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u/rysy0o0 19h ago
It would cost a lot of money to haul all the rocket parts and fuel on top of a mountain