Award-winning children’s science book author of more than 300 books, Seymour Simon, takes you on a trip from earth to infinity using his books as a guide at the inaugural X-STEM Symposium on April 24, 2014 in Washington, D.C. br The X-STEM Symposium is sponsored by MedImmune and the Northrop Grumman Foundation and is a program of the USA Science & Engineering Festival. br Lockheed Martin is the Founding and Presenting Host of the USA Science & Engineering Festival.