[Off-topic] Project ELF

[To be]

Very very off topic, but I don't think the relevant people would see it if I posted in the general forums. I didn't realize that Project ELF (the ELF communications system) had been shut down (in 2004). Apparently it was shut down as being obsolete, but I don't understand exactly what could replace it. Was it just shut down due to the controversy, or the cost, or is there actually some replacement for it out there that we don't know about? Has satellite communications just rendered it less useful, or are we less concerned about nuclear attack? A lot of questions...