A fairly recent study has shown that any reusable launch system would have to be used at a rate around 100 times that of the shuttle to be economically advantageous over an expendable system. I wonder how they missed that calculation back in the 70s? Each shuttle mission, no matter what it's carrying, costs as much or more than an ambitious multi-year robotics mission to Mars. And the $150 billion orbiting hotel in search of a real mission that sucks funds away from real space science, the ISS, should be disassembled and de-orbited immediately before it sucks even more money away from the robotic exploration of our solar system. Robotic missions not only generate vastly more scientific payback per dollar spent, but they don't risk lives and they develop robotic and AI technologies that are potentially useful here on Earth, too. Here's an interesting 1974 popular Science article on what a bargain the Space Shuttle would be: http://books.google.com/books?id=tE0idc3G364C&lpg=PA70&ots=oONm3QBO…