A planet is in orbit around a larger planet, and I want to push it out of orbit.
The planet has an average radius of 250 miles, and a mass of about 1.47x10^22 kg. The planet it is orbiting has a radius of about 3000 miles, and is about 1.5 times as dense. Assume they have a proportionate gravitational pull. I'm plucking the figures out of the air partly, but they give a general idea of size.
What force would I realistically need to break the planet free from it's orbit? Assume I have access to several tug-spaceships, what power would they need to be able to shift this?
You can include hard science to show what you've based your answer on, but I'm looking for some ideas of size of the ships and the power output required so I can make sure they are realistic.