The figure below shows three isolated planets, A, B and C on a grid where the spacing is a. The mass of the planets is M, M and 2M respectively.

The figure below shows three isolated planets, A, B and C on a grid where the spacing is a. The mass of the planets is M, M and 2M respectively. There is a small spaceship of mass m located at points P. Assume that the planets are fixed in position and the spaceship is initially at rest. Assume that the only force acting on the spaceship is the gravitational force due to the three planets.