For example, the radiation environment around the giant planet is the harshest and most intense in the solar system. Juno will have to withstand swarms of potentially damaging electrons accelerated to nearly the speed of light by Jupiter's magnetic field, which is 20,000 times more powerful than that of Earth.
"The minute they hit that spacecraft, they will ricochet and create shrapnel of photons and other particles, which will then scatter," said Heidi Becker of JPL, leader of Juno’s radiation-monitoring team. "And that's what gets in and degrades the electronics."
Juno's core electronics are protected by a 400-lb. (180 kilograms) titanium vault, which should keep them safe. But the team isn't taking anything for granted; the spacecraft will fly through the harshest part of Jupiter's radiation belts just as the engine is firing up for the orbital-insertion burn, Becker said.
Indeed, Juno will be exposed to the equivalent of 1 million dental X rays just during the orbital-insertion maneuver tonight, she added.
