 Major changes to the PAC-2 missile were the size of the projectiles in its blast-fragmentation warhead (changed from around 2 grams to around 45 grams), and the timing of the pulse-Doppler radar fuse, which was optimized for high-speed engagements (though it retained its old algorithm for aircraft engagements if necessary).Engagement procedures were also optimized, changing the method of fire the system used to engage ballistic missiles.Instead of launching two missiles in an almost simultaneous salvo, a brief delay (between 3 and 4 seconds) was added in order to allow the second missile launched to discriminate a ballistic missile warhead in the aftermath of the explosion of the first.