https://www.navalgazing.net/ESSM https://www.navalgazing.net/ESSM says the range is estimated to be 50km, Block II no longer needs illumination from the firing

https://www.navalgazing.net/ESSM https://www.navalgazing.net/ESSM says the range is estimated to be 50km, Block II no longer needs illumination from the firing ship, but may not be fully integrated into AEGIS such that it can take targeting data from other ships. “But despite its capabilities, ESSM still had the drawback of all previous versions of Sea Sparrow. It relied on semi-active guidance, requiring illumination from the firing ship. It did have an autopilot and uplink from the firing ship, allowing illumination only in the last moments of its flight, but this was still a potential problem when facing saturation attack. The obvious way to solve this was to fit the missile with an active seeker head, and discussions of doing so were happening as far back as 2002, but it wasn’t until relatively recently that serious work began on what is known as ESSM Block II. Block II kept the motor and fins, and replaced the forward 8″ section with a new 10″ guidance section, with a new dual-mode active/passive radar seeker. This removed the need for firing-ship illumination entirely, allowing Block II to be used against swarm attacks or targets that the firing ship couldn’t see, although reports don’t seem to indicate that it’s fully integrated into the Collective Engagement Capability (CEC) system.”