I wonder whether dark energy can be used for interstellar propulsion? For instance, will this setup theoretically work?
Put a massive object far ahead of a spaceship.
Connect it with a rope to the spaceship.
Now, due to space expansion the both spaceship and the heavy object experience force directed from each other. But the force is proportional to mass, so it is greater for the heavy object. So it will pull the spaceship via the rope against local stars in the spaceship's neighborhood.
A disadvantage is that this would require astronomically big distance between the object and the spaceship, and similarly long rope.
Are there other methods of using dark energy for propulsion?