A small asteroid of mass 2.6 X 10^9 kg is discovered traveling ar a speed of 18 km/s on a direct heading for Starbase Alpha, which is a in deep space outside of the solar system. Lacking weapons of sufficient power to destroy the asteroid, the frightened starbase inhabitants decide to deflect it by hitting it with a Remote control spaceship. The spaceship has an empty mass of 25,000 kg and a top speed of 85 km/s when its fuel is exhausted. The asteroid hast to be deflected so that by the time it reaches the star base, its center is 1800 m away from its original path. What is the minimum time before the asteroid's projected impact that the spaceship must reach before the asteroid? Explain carefully.