President Barack Obama talks with the crews of the Space Shuttle Atlantis and the International Space Station during a phone call in the Oval Office, Friday, July 15, 2011, in Washington. (Official White House Photo by Pete Souza)

President Barack Obama greets First Lady's box guest Scott Kelly following President ObamaÕs State of the Union address at the U.S. Capitol in Washington, D.C., Jan. 20, 2015. (Official White House Photo by Pete Souza) P012015PS-1206 This official White House photograph is being made available only for publication by news organizations and/or for personal use printing by the subject(s) of the photograph. The photograph may not be manipulated in any way and may not be used in commercial or political materials, advertisements, emails, products, promotions that in any way suggests approval or endorsement of the President, the First Family, or the White House.