The ISS is around 400km above us. A rocket needs a speed of at least 8km per second to get to space. If we cut out the acceleration part it could in theory reach the ISS in around 50 seconds. Even if we factor in the acceleration part etc. it should still be very quick up there. Yet the fastest possible time to get to the ISS is 4 hours. That would be an average speed of 100Km/h which is way slower than the speed of the rocket after a few seconds. Why the long journey?
In: Planetary Science
The people in the ISS want the rocket to approach them at approximately 0 speed, relative to the ISS (which is of course moving really fast). If you approach them at high speed, there is a collision and everybody dies.
It takes time to get into the right orbit and then very slowly approach the ISS.
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