What is the minimum work that has to be performed to bring a spaceship of mass 2000kg from the surface of the Earth to the Moon?

Answer 1

We would have to know the masses of the Earth and the Moon to figure that out. But I will tell you this: The minimum work done is the energy needed to get the spaceship to the point between the Earth and the Moon where the gravitational influences of the two celestial objects cancel each other. After it passes this point, the spaceship will be pulled towards the Moon by the Moon's gravitational attraction, thus eliminating the need to push the spaceship further.