We all know that we need a lot of fuel to escape from earth. Even 90% fuel of an spaceship is wasted in escaping the earth which definitely affect our power to explore the universe. we have to do a lot of calculations and even a small failure can waste a lot of money. for ex- the Manglayan Indian mission to Mars due to under performance of the engine was almost lost. As it a cheapest mission to Mars. They have a very limited fuel. So why can't we connect our space station with a long pipe and Make our space ship refuel at that point. I know a lot of energy will be required to pump the fuel up. But I was thinking about a better option. why can't we use vacuum to transfer liquid. Like if we have a pipe and we suck one end and the water automatically travels. Is it possible or what are the technical difficulty here.
A pump can lift water about thirty feet. That's the height where the column of water in the pipe weighs the same as an equivalent column of air (and that's why deep wells use submersible pumps: they push the water up from below, instead of pulling from above and relying on atmospheric pressure to provide the lift). While fuel would be less dense than water, it's still much more dense than air, and the pressure of the atmosphere simply doesn't provide enough force to raise that column of fuel very far.
The ISS travels over 7 kilometers per second, so the challenge of refueling would require bringing the pipe from Earth to the same speed as the ISS in order to make the connection. However, the pipe could be used to supply a stationary supply space station that has intermediate orbiters that connect the stationary supply station to the ISS. That is the idea of the space elevator.