Description Summary
Missile Defence Software is a system that allows ships to automatically react to missile attacks. It locks on to the incoming missile and launches a Mosquito Missile of its own, to destroy it and thereby serve as countermeasure. The software can be bought at a number of equipment docks and corporation headquarters and, once installed, is permanently operational as long as there are Mosquito Missiles in the cargo hold.
Detailed Info
Note that MDS is /not/ necessary for <playership> /manual/ use (though its manual function may require an explicit keybind in <settings>); neither do manual or automatic anti-missile measures require Mosquito missiles to be explicitly selected in <playership> loadout: they simply have to be in the ship's cargo. MDS simply automates the counter-missile launch for both <playership> & any NPC ship
Also note that to conserve your missiles, the MDS will not attempt to destroy all missiles, it determines which missiles to take down based on their destructive power and your current level of shields. If you shields can easily absorb the damage, a Mosquito is not wasted to take it down. Therefore some missiles will hit your ship3, but they shouldn't do much damage to you3