JUNO to Jupiter
The Juno trajectory took it initially beyond Mars’ orbit and then after a deep space manoeuvre back for an Earth flyby. Then it followed the outer cruise until Jupiter orbit insertion five years after launch.
After 20 months of science at Jupiter the mission is scheduled to end in February 2018 when Juno will be steered into the gas giant.
The insertion manoeuvre occurred at the spacecraft’s closest approach to Jupiter, and slowed it enough to be captured by Jupiter’s gravity into a 53.5-day orbit. In this way the spacecraft saved fuel as compared to going directly into the 14-day orbit required for the science mission.
Juno is in a highly eccentric, polar orbit over Jupiter and passes very close to the planet at its closest approach (jovelion). Juno needs to get extremely close to Jupiter to make very precise measurements required by the mission. This orbital path carries the spacecraft repeatedly through hazardous radiation belts, which are similar but much stronger than the Earth’s Van Allen belts. See this animation.