Summary: Project Pacific Intertie Strategic Communications ELF System (PISCES) was proposed as an alternative extremely low frequency (ELF) communication system to the proposed Project Seafarer. The proposal was to adapt the existing Pacific Intertie system to radiate an ELF signal.
The Department of Defense (DOD) believes that the advantages of using the Pacific Intertie as an ELF antenna system are: (1) there are no tap-offs of DC power between terminals; and (2) there are no AC carrier interaction problems. DOD planned a three-stage approach to studying the PISCES concept, but did not complete the studies because it was unable to obtain congressional approval. TRW Systems Group conducted an independent study of the feasibility of using the Pacific Intertie for ELF transmissions concluded that Project PISCES is technically feasible for ELF transmissions. The Science Advisory Group of the Defense Communications Agency concluded that, while PISCES is technically feasible, it should be considered as a possible fallback ELF system. These conclusions were based on: (1) indications that the proposed system would not provide desired coverage for all operational areas; (2) uncertainty about conductivity under the Pacific Intertie transmission line; and (3) uncertainties about cost.
