JUNO IS GO FOR JUPITER
After the Atlas V rocket launches Juno into space, it will place the spacecraft in a parking orbit, in which it coasts around earth. At a particular point in this orbit, the rocket will fire again to put Juno on course toward Jupiter. Before separating from Juno, a set of thrusters will fire to give the space-craft some spin. Once Juno is deployed from the rocket, its solar arrays unfurl to begin charging its batteries.
While on its way to orbit, Juno communicates with ground controllers using the antennas on the Atlas rocket. But once the spacecraft detaches from the last rocket stage, it will communicate with Earth directly. NASA’s Deep Space Network, which has giant antennas in California, Spain and Australia, will lock onto its signal.
Juno will spend two years cruising the inner solar system before its trajectory takes it to Jupiter.
TEST AS YOU FLY
Extensive testing is done to ensure Juno makes it to Jupiter
Test as you fly
THE FLIGHT PLAN
Juno’s trajectory takes it on a five-year voyage, circling the inner solar system before arriving at Jupiter.
The Flight PlanJuno launched in August 2011 and will take about five years to travel to Jupiter, first looping around the inner solar system and swinging past Earth to get a boost in its speed that will propel it onward to its destination. But why not send it directly to Jupiter?
Though the journey may seem long, Juno’s flight plan allows the mission to use Earth’s own gravity to speed the craft on its way. To get the necessary speed from a rocket would require a much more powerful launch vehicle and a lot more fuel. Lots of space missions have used this technique, called a gravity assist (also sometimes called a “gravitational slingshot”), to get to their destinations.
In July 2016, Juno will fire its main engine and slip into orbit around Jupiter’s poles to begin its investigation of the planet’s many exciting mysteries.
AMOUNT OF FUEL
Since there are no filling stations in space, Juno has to carry enough fuel for its entire trip.
Amount of fuelJuno carries six spherical propellant tanks – four containing fuel (called hydrazine) and two holding oxidizer (called nitrogen tetroxide). When the two propellants combine, they burn to give Juno thrust. Together, the propellants have a mass of just over 2,000 kilograms (4,400 pounds), accounting for 55 to 60 percent of the spacecraft’s mass at launch.
Aboard Juno, there are also 12 thrusters that fire bursts of hydrazine to adjust its rotation and orientation in space. In addition, Juno has two tanks of liquid helium, which provide pressure to the fuel lines, allowing the propellants to flow.