From a comment by the OP.
If you have gravitational pull even if your speed is greater than or
equal to escape velocity then what is the use of 11.2 km/s for a
javaprogrammer, to think that gravity somehow no longer affects the rocket after it attains escape velocity is to seriously misunderstand the nature of gravity.
The equation of motion that governs the rocket does not depend on the speed of the rocket.
For simplicity, consider the idealized case of just the Earth and the rocket.
The equation of motion tells us that the rocket, once the engine is shut down, will always have an acceleration towards the Earth no matter how fast the rocket may be travelling away from the Earth.
However, the equation of motion tells us something else, it tells us that, given a particular speed when the engine shuts off, there are three possible outcomes:
(1) the rocket will eventually slow, stop, and start travelling towards the Earth. This is the case that the rocket does not have escape velocity when the engine stops.
(2) the rocket will slow with its speed approaching zero but never quite getting there. This is the case that the rocket has exactly the escape velocity when the engine stops.
(3) the rocket will slow with its speed approaching some non-zero value but never quite getting there. This is the case that the rocket has greater than escape velocity when the engine stops.
Addendum to address comment by OP:
i saw in Discovery science in which they have said that NASA has sent
a spacecraft to move into outer solar system and it is run by slow
degradation of some radioactive element. And the fuel is little
sufficient till 2030. My question why does it require fuel at all
To produce electrical power to run the spacecraft systems.