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.
In: Engineering
The key factor for getting away from earth’s gravity isn’t how high you need to get, but how fast you need to go to stay away. For example, to launch to the ISS an orbiter needs to accelerate to at least 17,400mph / 8000m/s.
This is why vast quantities of fuel are needed, not just to lift the orbiter to the required height but impart the energy required to get it up to orbital speeds.
From that perspective, trying to gain height via atmospheric flight (wing lifted) is simply a waste of energy/fuel in a high drag environment.
Consider that when flying at 80,000ft and Mach3+, a supersonic plane generates enough frictional drag that the leading edges have to be titanium to avoid melting. The edge of space is at over four times that altitude (100km/328,000ft) and at some intermediate point wing lift will stop working unless the wings are unbelievably large.
Therefore, the vertical launch profile is a tool to punch through the atmosphere into a low drag environment as quickly as possible so speed can be gained efficiently. HTH.
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