One most interesting aerospace project that has managed to keep a relatively low profile is the American X37B reconnaissance spacecraft, as reported by the BBC http://www.bbc.co.uk/news/science-environment-16423881 and described on Wikipedia http://en.wikipedia.org/wiki/X-37B.
First going in to service (apparently) in April 2010, this vehicle is rather like a miniature un-manned version of the Space Shuttle, but it can stay in orbit for several months before returning to earth, landing on a runway just like the Shuttle.
While there is speculation about what surveillance technologies it can carry, and just what its principal roles are, I think it will probably be some decades before that becomes public information.
An interesting technical point is that R&D project which lead to the X37B used a propulsion system using that whacky old favourite hydrogen peroxide together with kerosene fuel. No surprise, however, that the operational vehicle has not used hydrogen peroxide, but is apparently using hydrazine and nitrogen tetroxide. As the great sage John D. Clark said so long ago about peroxide, “always a bridesmaid, never a bride”!