This would be fantastic! Does anyone know if this is in development or even being considered?
10 cells each of ESSM and ESSM ER would give Hunter and GPG 40 med Sam’s and 40 er sams each and 12 spare cells for mission specific, would help quite well with magazine depth!
Unfortunately nothing that I can find. I am sure there is development on an ESSM block 3 but it doesn't seem to be public.
The ESSM block 2 uses the mk134 rocket, which it shares with it's block 1 older sibling. It's quite big though at about 2 metres (so more than half the full missile length) and comes with a thrust vector control on the end. An option could be to add a second mk134 as a booster. Alternatively there are some other 10 inch rockets used for the larger air to air missiles that could be used if the mk134 is too big.
I don't know what its improved range would be with a booster, but it would not be unreasonable to consider 80-100km and say 20km altitude. That would give it some viability against medium range balistic missiles.
While this may not be much benefit to a large destroyer with a big magazine of SM2s, it would be very useful to a frigate with 16 or 32 cells. All the 17 nations who participate in the ESSM consortium have (or will soon have) small frigates.
As NASAMS can use the AMRAAM ER, which has the body of the ESSM, any extended range could be useful in this application as well.
Adding a booster is however complex. It can impact its short range capability for instance, which is important to engage leakers, and it changes the vectoring controls.
I suspect we will not hear about a block 3 this side of the turn of the decade.