Intro to the task

I am working on a simulating the orbit of moon Phobos around the planet Mars. I have completed the task of using numerical integration to update the velocity and position of both bodies. My final task is to produce an animated plot of the orbit of Phobos, with Mars centred at its initial position.

Code snippet

# plot the animated orbit    def plot_orbit(self):        # load all the data from the json file        all_data = self.load_data_for_all_bodies()        # get the positions and velocities as 2d vectors        positions, velocities = self.simulate()        # Create a figure and axis        fig = plt.figure()        ax = plt.axes()        mars_initial_pos_x = all_data["Mars"]["initial_position"][0]        mars_initial_pos_y = all_data["Mars"]["initial_position"][1]        print("mars: ", mars_initial_pos_x, mars_initial_pos_y)        phobos_initial_pos_x = all_data["Phobos"]["initial_position"][0]        phobos_initial_pos_y = all_data["Phobos"]["initial_position"][1]        print("phobos: ", phobos_initial_pos_x, phobos_initial_pos_y)        # Set the limits of the axes        ax.set_xlim(-9377300, 9377300)        # mars as a red circle        mars_circle = plt.Circle(            (mars_initial_pos_x, mars_initial_pos_y),            4,            color="red",            label="Mars",            animated=True,        )        ax.add_patch(mars_circle)        # Phobos as a blue circle        phobos_circle = plt.Circle(            (phobos_initial_pos_x, phobos_initial_pos_y),            80,            color="blue",            label="Phobos",            animated=True,        )        ax.add_patch(phobos_circle)        # Function to update the position of Phobos        def animate(frame):            phobos_circle.center = (positions[frame][0], positions[frame][1])            return (phobos_circle,)        # Create the animation        ani = FuncAnimation(            fig, animate, frames=self.iteration_counts, interval=20, blit=True        )        plt.title(f"Orbit of {self.name}")        plt.xlabel("x (m)")        plt.ylabel("y (m)")        plt.legend()        plt.show()

Data file(JSON)

{"Mars": {"mass": 6.4185e+23,"initial_position": [            0,            0        ],"initial_velocity": [            0,            0        ],"orbital_radius": null    },"Phobos": {"mass": 1.06e+16,"orbital_radius": 9377300.0,"initial_position": [            9377300.0,            0        ],"initial_velocity": [            0,            2137.326983980658        ]    }}

Output

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In the above output I can see that the positions and velocities array has been correctly filled because of my previous methods. However, the graph that is produced is a complete disaster. I ran the code in Jupyter notebook and VS code, Jupyter notebook does this and VS code prints nothing out on the screen. My first step is to get circles on the graph in the correct positions initially and then think about the animate function. Sadly, I can't see any circles in the output. I used very similar code that was given in the answer to a question about FuncAnimation on stack.

Any help would be appreciated!