Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with a mass slightly less than one-thousandth of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn, Uranus and Neptune. Together, these four planets are sometimes referred to as the Jovian or outer planets.

Juno Spacecraft
Juno was carefully designed to meet the tough challenges of flying a mission to Jupiter: weak sunlight, extreme temperatures and deadly radiation. The spacecraft is covered in thermal blankets to protect from the extreme environment of space. All of the most sensitive electronics are placed inside of an armored vault to protect them from Jupiter's deadly radiation.

Source: Mission Juno