1. Originally, Kusha was known as XRSAM and was supposed to have a range of 250km.
2. Later DRDO modified the system and now Kusha was supposed to have two missiles i.e. ERSAM with 150km range and XRSAM with 350km range. The whole system was dubbed as ERADS or Extended Range Air Defence System.
3. The Kusha system was given a new programme name i.e. PGLRSAM which stands for Programme Long Range Surface to Air Missile. It was now supposed to have three missiles.
4. The three missiles were known as M1, M2 and M3. The M1 missile was expected to have a range of 80km and it was not supposed to have any external booster attached to it.
5. The M1 missile was very similar in looks and performance to Akash-NG.
6. The M1 missile was to fill the role of Kill Vehicle for M2 and M3 missiles having ranges 250km and 350km respectively.
7. M2 and M3 missiles were shown to have big boosters attached to it for achieving the expected ranges.
8. Now, in the latest iteration: all the three missiles i.e. M1, M2 and M3 are going to have an external booster attached to them. M1, M2 and M3 will have ranges of 150km, 250km and 350km respectively.
