Traveling through our solar system, a spacecraft with a mass of 4.00 x 10^5 kg maneuvers to avoid collisions. The spacecraft detects two asteroids. Asteroid 1 is located directly behind the craft at a distance of 5.00 x 10^8 m and has a mass m = 2.50 x 10^20 kg. Asteroid 2 is 3.00 x 10^6 m directly in front of the craft and is twice as massive as asteroid 1 (M = 2m).
What is the magnitude and direction of the net gravitational force on the spacecraft due to these two asteroids at this time?