July 4, 2016[CLICK ON IMAGE FOR HIGH RESOLUTION]
NASA’s Juno spacecraft was to fire its main rocket engine late Monday to slow itself down from a speed of 150,000 mph (250,000 kph) and slip into orbit around Jupiter. With Juno on autopilot, the delicately choreographed move comes without any help from ground controllers.
The spacecraft is traveling through a hostile radiation environment and rings of debris and dust, “making for very serious hazards,” Juno chief scientist Scott Bolton said during a morning briefing. But Juno should be able to withstand the harsh conditions because it’s “built like an armored tank,” he said.
The spacecraft’s camera and other instruments were switched off for arrival, so there won’t be any pictures at the moment it reaches its destination. … Juno’s mission: To peer through Jupiter’s cloud-socked atmosphere and map the interior from a unique vantage point above the poles. Among the lingering questions: How much water exists? Is there a solid core? Why are Jupiter’s southern and northern lights the brightest in the solar system? …
Plans called for Juno to swoop within 3,000 miles (5,000 kilometers) of Jupiter’s clouds — closer than previous missions — to map the planet’s gravity and magnetic fields. Juno, built by Lockheed Martin, is an armored spacecraft — its computer and electronics are locked in a titanium vault to shield them from harmful radiation. Even so, Juno is expected to get blasted with radiation equal to more than 100 million dental X-rays during the mission.
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