An Atlas V rocket starts the Juno spacecraft on a five-year journey to study the planet Jupiter. Liftoff occurred at 12:25 p.m. on 5 August 2011 from Cape Canaveral Air Force Station.

Excerpts from NASA’s Juno Launch Press Kit and the Juno Fact Sheet:

If you take everything else in the solar system (not including the Sun), it would all fit inside Jupiter. . .

The largest and most massive of the planets was named after the king of the gods, called Zeus by the Greeks and Jupiter by the Romans; he was the most important deity in both pantheons.

The Juno spacecraft will, for the first time, see below Jupiter’s dense cover of clouds. This is why the mission was named after the Roman goddess, who was Jupiter’s wife, and who could also see through clouds.

During its mission, Juno will map Jupiter’s gravity and magnetic fields to learn what the planet’s interior structure is like. The spacecraft also will observe the composition and circulation of the deep atmosphere and improve our understanding of the forces that control the planet’s powerful auroras. In addition to expanding our knowledge of the solar system’s largest planet, these investigations will provide clues about what conditions in the early solar system were like when Jupiter was forming. Improving our knowledge of Jupiter’s origins and evolution will also help us to better understand the many planetary systems being discovered around other stars.

Juno’s trip to Jupiter will take about five years. Though the journey may seem long, this flight plan allows the mission to use Earth’s gravity to speed the craft on its way. The spacecraft first loops around the inner solar system and then swings past Earth two years after launch to get a boost that will propel it onward to its destination.

In July 2016, Juno will fire its main engine and slip into orbit around the giant planet to begin its scientific mission.