Juno’s main body is made of an advanced carbon composite material in a honeycomb structure. The spacecraft has a hexagonal shape, with three large solar arrays symmetrically placed around the hexagon. Most of the science instruments are between the solar arrays, with their sensors attached to Juno’s main deck. The instruments’ electronics are housed inside Juno’s titanium vault, atop the main deck, which provides the base for Juno’s main antenna. Beneath the main deck reside the propellant tanks and Juno’s rocket engine that’s used for maneuvers and orbit insertion.    

The Juno mission benefits from three important firsts:

• Juno is the first spacecraft to go into orbit around the poles of one of the gas giant planets of the outer solar system.
  
• It is the first solar powered spacecraft to visit the outer solar system.
  
• The spacecraft is the first to carry a specially designed vault to shield its sensitive electronics from dangerous radiation in space.    
  

Space is a harsh and unforgiving environment. Impacts from micrometeors could cause grave damage to an unprotected spacecraft. Temperatures tend to be scorching hot or extremely cold, without any air to circulate in order to keep a spacecraft from overheating or freezing. Juno faces an especially tough challenge from the intense belts of charged particle radiation that surround Jupiter. To meet these threats, engineers protect the robotic explorer with a shiny skin of insulation and a unique protective shield for its electronics.

The shiny blankets on Juno’s exterior protect the spacecraft from micrometeoroid strikes and act as insulation. The material also helps electricity to flow over the spacecraft in the charged environment around Jupiter – electrons that can’t flow build up as an electric charge, which can be unleashed as a dangerous spark. Juno’s shiny skin is its best defense against these threats.