What is Juno? Juno is a spacecraft enroute to Jupiter. The unique trajectory Juno is taking to Jupiter requires less delta-v than a direct (Hohmann transfer) route. After a single orbit of ~2 years, Juno returned and flew by Earth to get a gravitational assist to Jupiter. Because the assist came from Earth, Juno could launch whenever the phase angle between Earth and Jupiter was right and didn't have to wait for other bodies (like Mars) to be in the right spot. Who cares? This method can be