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-----------------------------1903 - Juno’s mission arriving at Jupiter
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- The spacecraft “ Juno” made its closest approach August 29, 2016 in the first fly-by of the planet Jupiter. It was only 2,600 miles above the surface. It will be days before all the data being collected will begin to be analyzed and months before science can comprehend the new things to be learned.
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- The measurements are being made on the gravitational and magnetic fields, on the deep winds on the surface, and on the planet’s composition. The robotic probe is expected to continue its mission orbiting until February, 2018. Juno was launched August 5, 2011. Five years later it enters its orbit around this enormous gaseous planet after traveling 1.74 billion miles.
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- In order to get a boast of speed Juno had looped around Earth in a fly-by August 9, 2013. Stealing angular momentum from Earth’s gravity it gained another 8,800 miles per hour, reaching the Jupiter system traveling 165,000 miles per hour. ( See Review #1902 regarding the calculations using the Conservation of Angular Momentum ).
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- Juno becomes the fastest man-made object until it fires its engines for 30 minutes to put it into a 53.5 day orbit around Jupiter. The orbit is highly elliptical between 3,100 miles and 1,170,000 miles from the surface. A new orbit will eventually be reduced to 14 days allowing a total 37 orbits in its 20 month mission.
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- Juno carries nine instruments to explore the interior of the atmosphere. To map the gravity and magnetic fields. To track water in the atmosphere. To take pictures of the swirling clouds, the polar region, and the auroras at the poles.
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- The data collected takes 48 minutes, 19 seconds to return to Earth, if all goes well. Juno will be immersed in a strong and variable magnetic field and hazardous radiation. To shield the instruments they are surrounded by a 400 pound titanium vault. Titanium is radiation resistant. It will need it. The spacecraft must endure the equivalent of 100 million X-rays. The camera will have image resolution at 1.8 miles per pixel at its closest approach. ( Visit www.missionjuno.swri.edu/junocam ).
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- Juno is powered by a trio of 29 feet solar arrays that output 500 watts. These solar arrays will receive only 4% as much sunlight as they would orbiting Earth.
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- The instruments will map the deep winds that reach speeds of 384 miles per hour. The atmosphere consists of mostly hydrogen and helium, about the same ratios as our Sun. The instruments hope to measure the global water and ammonia that are in the atmosphere.
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- The magnetic field to be mapped is 1,000 times stronger that Earth’s. This map is created orbiting over the poles. It is designed to help science learn the origin of Jupiter’s magnetism and the nature of the planet’s core. Juno’s microwave radiometer will profile temperatures to a dept of 220 miles where pressures are 200 times Earth’s atmospheric pressure. This radiometer is only expected to survive for 11 orbits.
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- Measurements will be made of the ratio of oxygen to hydrogen and of the amount of water that exists in the atmosphere. Deep in the atmosphere the gravity is so intense that electrons are stripped form the hydrogen atoms and plasma becomes electrically conductive liquid metallic hydrogen. Science thinks this shell of metallic hydrogen might be the source of Jupiter’s magnetic field.
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- The magnetic field generates powerful auroras at the cloud tops that is 1,000 times stronger than Earth’s auroras.
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- Juno’s orbit crosses the paths of moons, Europa, Ganymede, and Callisto making it imperative that there is never an impact to cause pollution. Therefore in 2018 Juno will be sent into Jupiter’s atmosphere to disappear for good.
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- The end of Juno’s mission, February, 2018. But, the data will be analyzed for years to follow. Stay tuned, an announcement will be made shortly.
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- Other reviews available on this subject:
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- #1880 - More about the Juno mission
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- Lists 4 other reviews about Jupiter’s moons and rings.
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