A Sputnik moment is a point where people realise that they are threatened of challenged and have to redouble their efforts to catch up.
Obama followed his Energy Secretary Steven Chu in declaring that the United States stands at a new "Sputnik moment" in the development of such technologies as clean energy and high-speed rail. The idea has been percolating for several years now: Robert J. Samuelson of Newsweek and Mort Zuckerman of U.S. News & World Report both used the expression in 2005. It's unclear whether Americans listening to Obama will be moved by the historical reference, particularly those too young to appreciate the threat that the Soviet launch of the Sputnik satellite represented during the Cold War era. Obama continued the aeronautical allusions by referring to new energy innovation projects as the "Apollo projects of our time."
Sources: Using English
"Commander in Speak: Parsing Obama's Speech", CBSNews
"Choice Words from the State of the Union", Visual Thesaurus