Ground controllers at the NASA Jet Propulsion Laboratory erupted in applause when the solar-powered spacecraft beamed home the news it had entered the planet's orbit.
"Juno, welcome to Jupiter," said mission control commentator Jennifer Delavan of Lockheed Martin, which built Juno.
The four-ton Juno launched on Aug. 5, 2011, and is equipped with three 30-foot-long solar arrays, along with 18,696 individual solar cells, to help it make the most of the solar power it receives on its journey.
The spacecraft conducted a 35-minute burn of its main engine Monday, essentially hitting the brakes and slowing Juno by about 1,200 mph so it can enter Jupiter's polar orbit.
Once inserted into Jupiter's orbit, Juno will circle the giant planet a total of 37 times over the course of 20 months. During that time, Juno is set to come as close as 3,100 miles above Jupiter's cloud tops, getting our closest look ever at the planet.
The Juno probe gets its name from the Roman goddess and wife of Jupiter who was able to see through clouds.
NASA officials said they hope the mission will help scientists learn more about Jupiter's origins, structure, atmosphere and magnetosphere.