US Navy SQUID magnetic anomaly detection program

Late 1980s Navy concern that Soviet satellites equipped with HTSC-based SQUID detectors would render steel-hulled submarines visible from orbit. The applied motivation for both titanium and stainless-steel submarine programs.

I said they may be important for detecting magnetic fields, in what's called SQUID — superconducting quantum interference devices. The US Navy got very concerned in the late 80s that the Soviets would be able to put a SQUID in a satellite, and all of a sudden these big magnetic submarines would be magnetically visible in the whole ocean. They'd light up like a light bulb to a SQUID detector. At the time, you could fly an aircraft at 10,000 feet above the ocean with a SQUID detector and you could find the magnetic field signature of the steel submarines. The US Navy ever since has wanted to build a titanium submarine because it's non-ferromagnetic. They now want to build a stainless steel submarine because it's non-ferromagnetic. They want to get rid of this lousy ferromagnetic iron because superconductors can detect those submarines. The question is, could they do it from 100 miles in the air? With high-temperature superconductors it might have become possible. People were talking about magnetically levitated trains and all these wonderful things, and I said, you're not going to see magnetically levitated trains and big high-field magnets in our lifetimes or our grandchildren's lifetimes. There's the sound bite that someone will remember — we won't see it in our grandchildren's lifetimes.