 NASA launched Juno on August 5 , 2011 to study Jupiter in detail from a polar orbit when it arrives in 2016 . The spacecraft will be placed in a polar orbit to study the planet 's composition , gravity field , magnetic field , and polar magnetosphere . Juno will also search for clues about how Jupiter formed , including whether the planet has a rocky core , the amount of water present within the deep atmosphere , and how the mass is distributed within the planet . Juno will also study Jupiter 's deep winds , which can reach speeds of 600 km / h . Juno started orbiting Jupiter on the night of 4th July 2016 . 
