The Juno spacecraft, atop an Atlas 551 launch vehicle, lifted off from Kennedy Space Center on August 5, 2011. The spacecraft uses an energy efficient Delta V-EGA trajectory in transit to Jupiter ('delta V, Earth gravity assist'). This trajectory used deep space maneuvers on 30 August 2012 and 14 September 2012 followed by an Earth gravity assist (close flyby) on 9 October 2013, during whichit passed by the Earth at an altitude of approximately 500 km.
Jupiter arrival (orbit insertion) occurs on 5 July 2016. The capture orbit and orbit to follow will be 53.5-day orbits prior to commencing operations. Juno's year-long prime mission (one Earth year) consistsof 32 or more high inclination, high eccentricity orbits of Jupiter.
The orbit is polar (90 degrees inclination) with a periapsis altitude of about 4500 km and a semimajor axis of 19.91 RJ; the corresponding orbital period is 10.9725 days (Earth days). An alternative scienceorbit period of 14-days is also under consideration at this time.
The primary science is acquired during approximately 6 hours centered on each periapsis. However, fields and particles data are acquired at lower rates for the remaining portion of each orbit. All orbits will include fields and particles measurements of the planet's auroralregions.