http://www.straightdope.com/columns/030307.html “Why are we in space?” The Stennis Space Center FAQ explains that NASA’s funding represents a penny out of every dollar in the U.S. federal budget and that “diverting this money into social programs would provide a very minimal increase for those immediate needs, while eliminating resources devoted to the future and new solutions to problems.” (I don’t think NASA itself is necessarily bad value, though sending people into space might be.)
(NASA used to have a more official “justification” page on one of their sites but I can’t find it now. It was pretty weak, I recall.) 11:15
