Vintage space toys (particularly robots and ray guns) have a long history. The first toy robot -- called Lilliput -- was produced in Japan in 1938. Production ceased during the war, but started up again in 1949 with Atomic Robot Man. (Which, incidentally, was used as a piece of swag at NYC's Hydracon in 1950). The "Golden Age" of tin robot manufacture (as most people see it) lasted until the late Sixties; by then, the actual space race sucked some of the whimsy out of robots, rockets, and ray guns, and many of the toys opted for a more realistic -- relatively speaking -- approach to design.
The toys themselves are quite collectible, and range in price from a hundred bucks or so to many, MANY thousands of dollars. But there are enough fantastic pieces at the lower end of that scale for nearly anyone to build a nice sized collection of great toys.
I've written about my own collection of robots and space guns (and have posted photos) at my blog, Doc Atomic's Attic of Astounding Artifacts (astoundingartifacts.blogspot.com).
There's also a great forum for the discussion of these toys called Alphadrome, at www.danefield.com/alpha. Hundreds of members, many of them active; it's a deep resource for people interested in these toys.
There's even an actual, brick-and-mortar museum dedicated to toy robots: The Toy Robot Museum in Adamstown, PA. In fact, the museum often plays host to the only vintage space toy convention, Botstock (no, I didn't name it...).
It's a surprisingly thriving hobby, all things considered. The question, of course, is whether it will continue to attract fans once a certain generation dies off or loses interest. Or are there enough younger collectors -- like myself -- who find these toys fun and interesting despite not having grown up with them. Time'll tell, I guess...