[brd]

The US was researching comparable systems (and smaller) back in the mid 2000s. I knew a few people involved in those programs and seriously considered joining. Things went very quiet on that front, I've heard no news on those programs in years. I don't know if that means they continued behind closed doors or were put on indefinite pause.

This is the best article I could find on the subject which gives some background as to what derailed the program. http://strangehorizons.com/non-fiction/articles/what-killed-...