The spacecraft launched on August 5, 2011 to start its six year mission, culminating in a Jupiter arrival in 2016. The probe's trajectory included a flyby of Earth designed to conserve fuel. Unlike previous missions to the outer Solar System, Juno's energy will come only from solar panels, despite the relative dimness of the Sun at Jupiter's orbit.
|Juno's trajectory from launch in 2011 to arrival at Jupiter in 2016.|
In 2012, Juno executed several deep-space-maneuvers that prepared the probe for its flyby of Earth. Next, in October 2013, Juno completed its Earth flyby, assuming a trajectory directly toward Jupiter.
On July 4, 2016, the spacecraft executed an engine burn that inserted it into orbit around Jupiter. The probe assumed a highly elliptical orbit that took it past the north and south poles of Jupiter with every revolution.
The image above shows Juno's orbits around Jupiter over time, beginning with the orbital insertion on July 4.
This image, Juno's first acquired from orbit, shows the gas giant as well as three of the four Galilean moons, Io, Europa, and Ganymede (from left to right).
After its initial insertion burn, the Juno spacecraft spent over two months completing an elongated orbit that took it far away from the Solar System's largest planet. The first of 37 science flyby took place on August 27 and brought Juno over the north pole of Jupiter, capturing the first ever image of this polar region (see below).
The polar region is very different in appearance than the midlatitudes and equatorial region of Jupiter. The latter regions have characteristic colored bands of red, white, and orange, as well as prominent storm features. The poles are bluer, and lack these storm features.
Juno's path will take it just over 3,000 miles from the cloud tops near the poles, and will allow extensive observations of aurorae and other magnetic field phenomena. However, such an orbit also leaves Juno exposed to high concentrations of radiation, which will slowly degrade the functionality of the spacecraft. Juno is therefore planned to spend just over a year at Jupiter, making 33 orbits, before intentionally crashing into Jupiter late in 2017.
Juno will hopefully provide further information concerning the formation and evolution of Jupiter, specifically about its interior, about which little is known.
Sources: https://www.missionjuno.swri.edu/news/juno_spacecraft_in_orbit_around_mighty_jupiter, https://www.nasa.gov/feature/jpl/nasa-s-juno-spacecraft-sends-first-in-orbit-view, http://www.nytimes.com/2016/07/05/science/juno-enters-jupiters-orbit-capping-5-year-voyage.html?_r=0, https://www.nasa.gov/feature/jpl/jupiter-s-north-pole-unlike-anything-encountered-in-solar-system