Since 2011, our Juno spacecraft has been heading towards Jupiter, where it will study the gas giant’s atmosphere, aurora, gravity and magnetic field. Along the way, Juno has had to deal with the radiation that permeates space.
All of space is filled with particles, and when these particles get moving at high speeds, they’re called radiation. We study space radiation to better protect spacecraft as they travel through space, as well as to understand how this space environment influences planetary evolution. Once at Jupiter, Juno will have a chance to study one of the most intense radiation environments in our solar system.
Near worlds with magnetic fields – like Earth and Jupiter – these fast-moving particles can get trapped inside the magnetic fields, creating donut-shaped swaths of radiation called radiation belts.
Jupiter’s radiation belts – the glowing areas in the animation below – are especially intense, with particles so energetic that they zip up and down the belts at nearly the speed of light.
Earth also has radiation belts, but they aren’t nearly as intense as Jupiter’s – why? First, Jupiter’s magnetic field is much stronger than Earth’s, meaning that it traps and accelerates faster particles.
Second, while both Earth’s and Jupiter’s radiation belts are populated with particles from space, Jupiter also has a second source of particles – its volcanically active moon Io. Io’s volcanoes constantly release plumes of particles that are energized by Jupiter’s magnetic field. These fast particles get trapped in Jupiter’s radiation belts, making the belts that much stronger and more intense.
In addition to studying this vast space environment, Juno engineers had to take this intense radiation into consideration when building the spacecraft. The radiation can cause instruments to degrade, interfere with measurements, and can even give the spacecraft itself an electric charge – not good for something with so many sensitive electronics.
Since we know Jupiter is a harsh radiation environment, we designed Juno with protections in place to keep it safe. Most of Juno’s electronics live inside a half-inch-thick titanium vault, where most of the radiation can’t reach them. We also planned Juno’s orbit to swoop in very close to Jupiter’s surface, underneath the most intense pockets of radiation in Jupiter’s radiation belts.
Juno arrives at Jupiter on July 4th. Throughout its time orbiting the planet, it will send back data on Jupiter’s magnetic field and energetic particles, helping us understand this intense radiation environment better than ever before.
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