As Americans launch fireworks on Monday, NASA’s Juno spacecraft will be going through a trial by fire, as it will get its first exposure to the solar system’s most intense radiation environment, according to Space.com.
During the night of July fourth, Juno will fall into orbit around Jupiter, where it will be hit by a barrage of electrons moving at nearly the speed of light by the planet’s potent magnetic field.
“Once these electrons hit a spacecraft, they immediately begin to ricochet and release energy, creating secondary photons and particles, which then ricochet,” said Heidi Becker, the leader of Juno’s radiation-monitoring team, during a news conference. “It’s like a spray of radiation bullets.”
Juno needs to survive for more than a year
And Juno will have to survive this hail of bullets for about a year and a half, so that it can study Jupiter for the span of 37 orbits. After that, in February of 2018, Juno will plunge into the planet’s atmosphere—thus preventing the probe from accidentally introducing Earth microbes to Europa, one of Jupiter’s moons, which may already host life outside of our planet.
In order to keep Juno from frying prematurely, the team has devised a plan to both minimize radiation exposure and reduce its effects on the spacecraft. For example, the orbit Juno is planned to take will help it avoid Jupiter’s intense radiation belts as much as possible.
Beyond that, Juno is decked out in a sort of radiation Kevlar; its core is covered by a 400-pound (180-kg), 0.5-inch (1.75-cm) thick titanium suit. This should lower the radiation exposure of the probe’s main computers and the more sensitive components of several of its scientific instruments by 800 times (as compared to the outside). The outer parts of the scientific instruments are similarly protected, along with Juno’s star-tracking camera, which is used to help it navigate.
“Without that protection, the noise from the penetrating radiation would be too high to see stars, and Juno would never know where it was pointing,” said Becker.
But as long as all of this works to plan, Juno should be well-protected for doing its job—which mainly will involve mapping the gravitational and magnetic fields of the planet, as well as determining its composition and inner structure. Of particular interest is how much water is in Jupiter’s atmosphere, as well as whether or not it has a core, which can help scientists understand how, when, and where the planet formed.
Yet despite all this careful work, there is always a bit of concern when heading off into the unknown.
Jupiter has the scariest radiation environment of any planet in the solar system,” said Becker. “It’s the harshest, it’s the most intense and it hasn’t been fully explored yet — and it hasn’t been fully explored where we’re going.”
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Image credit: NASA
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