An electric line of force is an imaginary straight or curved path along which a small positive test charge is supposed to move when free to do so.
The tangent at a point on an electric line of force gives the direction of the resultant electric field at that point.
The relative closeness of electric lines of force in a certain region provides us an estimation of the electric field strength in that region.
In a satellite, there is condition of weightlessness.
Therefore, mg = 0.
On account of electrostatic force of repulsion between the balls, the strings would become horizontal.
Therefore, angle between the strings = 180°.
Also, tension in each string = force of repulsion