For those of you not in the know, the UNSC Fox Cannon was a high tech mobile artillery vehicle originally slated for Ensemble Studio's Halo Wars RTS game. The vehicle made it far enough in the development process that there was good concept art and a reasonably thorough description of its capabilities. Well I guess an artillery piece capable of targeting enemies up to 50km distant was considered a little over powered because the vehicle was cancelled from the game. Bummer as it both looked and sounded very cool. So just what was so high tech about a mobile howitzer 500 years in the future you ask? Well the munitions were accurately guided to the target using what sounded much like GPS satellite guidance. So while the munitions were ballistic, they must have deployed little guidance fins after emerging from the cannon barrel. It makes me think that if the Fox Cannon had made the game and then transitioned into the Bungie/343 Halo universe, final guidance for the munitions would have been courtesy of the existing in-game laser Target Designator. Also in light of the Fox Cannon's range and firing rate of five shots per minute, the cannon could be set up at 20-50km from the target and then use "time on target" shelling techniques where the gun barrel starts at a high angle of elevation and then drops a precise amount between each successive shot so that all 5 rounds arrive at the target near simultaneously.