system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 why do space rockets take off from a upright position instead of taking off of a runway like a plane, reach 40,000 ft and entering space from there.
gpt
A rocket has to go really fast to reach speeds fast enough to orbit, and the atmosphere is thickest close to the ground. So a rocket tries to get out of the thickest part as fast as it can to save fuel, then it turns sideways to get to orbital speeds. Basically it would waste too much fuel going through the atmosphere like a plane.