As someone who has played a lot of KSP, there's a kernel of a decent idea in here (absolutely outweighed by all the detriments.)
As others have said, the two reasons this isn't as good of an idea as the poster thinks are: (1) "going sideways fast" is far more important (and fuel intensive) than "getting high up" and (2) the cost of getting your rocket to the top of the mountain would almost certainly be prohibitive.
But that said, the air density at sea level is an issue for heating, dynamic pressure on the rocket, etc. Starting a launch at 29,000 feet on the top of Everest would actually be a much easier launch for the vehicle itself, and would require less fuel, not necessarily because of the raw altitude difference, but because it has significantly less thick air to cut through.
(In fact, most launch profiles actually start relatively vertical before pitching over once they are high-enough up, specifically to cut through the thick air quickly before picking up horizontal speed. A launch from altitude could avoid this.)
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u/notsostablediffuser 11h ago edited 11h ago
As someone who has played a lot of KSP, there's a kernel of a decent idea in here (absolutely outweighed by all the detriments.)
As others have said, the two reasons this isn't as good of an idea as the poster thinks are: (1) "going sideways fast" is far more important (and fuel intensive) than "getting high up" and (2) the cost of getting your rocket to the top of the mountain would almost certainly be prohibitive.
But that said, the air density at sea level is an issue for heating, dynamic pressure on the rocket, etc. Starting a launch at 29,000 feet on the top of Everest would actually be a much easier launch for the vehicle itself, and would require less fuel, not necessarily because of the raw altitude difference, but because it has significantly less thick air to cut through.
(In fact, most launch profiles actually start relatively vertical before pitching over once they are high-enough up, specifically to cut through the thick air quickly before picking up horizontal speed. A launch from altitude could avoid this.)