NASA officials cheer the New Horizons spacecraft's flyby of Pluto at the Applied Physics Laboratory
NASA Principal Investigator for New Horizons mission Alan Stern (L) and Co-Investigator Will Grundy (R) hold up an enlarged, out-dated U.S. postage stamp with the "NOT YET" crossed out, during the celebration of the spacecraft New Horizons flyby of Pluto, at NASA's Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, July 14, 2015. REUTERS/Mike Theiler