This anti-population weapon is condemned by all civilized governments, and used by many of them. It is typically directed at lightly-defended factory worlds far behind the battle lines, to disrupt the enemy economy.
Once fired, the A-90 travels at a speed of 200 to its target world. If it finds no defending forces, it goes into orbit and calls for a surrender . . . which always occurs. Otherwise, it attacks!
It does no damage on the first combat round; this is its "run-in" to the world. If it is not destroyed in the first combat round, though, it strikes and does its damage on the second round. It has a very small chance of actually destroying an enemy unit . . . but the tailored viruses it releases will kill 50 Population.