After the Atlas V rocket launched Juno into space, it placed the spacecraft in a parking orbit, in which it coasted around Earth. At a particular point in this orbit, the rocket fired again to put Juno on course toward Jupiter. Before separating from Juno, a set of thrusters fired to spin up the spacecraft along with its upper stage. Once Juno separated from the rocket, its three large solar arrays unfurled to begin charging its batteries.
While on its way to orbit, Juno communicated with ground controllers using the antennas on the Atlas rocket. But once the spacecraft detached from the last rocket stage, it began communicating with Earth directly. NASA’s Deep Space Network, with giant antennas in California, Spain and Australia, locked onto its signal.
Juno spent two years cruising the inner solar system before arriving at Jupiter.
Extensive testing is done to ensure Juno makes it to Jupiter
Juno’s trajectory takes it on a five-year voyage, circling the inner solar system before arriving at Jupiter.
Since there are no filling stations in space, Juno has to carry enough fuel for its entire trip.