FILE - In this April 4, 2011, file photo, school children look from a viewing gallery at NASA engineers working on the rover Curiosity at the Mars Science Laboratory, at the Jet Propulsion Laboratory in Pasadena, Calif. (AP Photo/Damian Dovarganes, File)
Juno Project Manager Rick Nybakken holds a model of the Juno spacecraft as he discusses the orbit it will take around Jupiter during a briefing at the Jet Propulsion Laboratory in Pasadena, California, on Monday. (Associated Press)
John Callas, Mars Exploration Rovers project manager, with a one-tenth Rover scale model, speaks at a news conference marking the 10th anniversary of the NASA Mars Opportunity rover mission, at a news conference at Jet Propulsion Laboratory in Pasadena, Calif., Thursday, Jan. 23, 2014. (AP Photo/Reed Saxon)