Fresh images of NASA's Juno spacecraft reveal an ethereal shadow cast by Jupiter's volcanic moon Io on the planet's swirling cloud cover.
The JunoCam imager has captured views of Io's clear shadow on Jupiter during his final passage near the Giant Planet, and experienced amateur image analysts immediately began processing the data into dazzling renderings that swirled a black circle in the midst of Jupiter's Show clouds.
Juno discovered the solar eclipse during a Sept. 12 encounter near Jupiter, the 22th such flyby since arriving on July 4, 2016, in orbit around the largest planet in the solar system. The spacecraft carries instruments to study the internal structure and weather of Jupiter and sensors to measure and map the planet's strong magnetic field and gravity.
Io is the most volcanically active object in the solar system. Scientists have found hundreds of volcanoes on Io, many of which emit lava and gas fountains hundreds of miles above the lunar surface.
The volcanoes are caused by the immense gravity of Jupiter in conjunction with the weaker gravity of Jupiter's Moon Europa. The gravitational forces tug at Ios interior, move the rock material inside the moon and generate frictional heat.
The overheated molten rock or magma breaks through numerous geyser-like volcanoes and produces distinctive clouds that reach far beyond Io. Jupiter's volcanic moon is also covered by lava lakes and has a thin atmosphere of sulfur dioxide, a gas released during volcanic eruptions.
NASA's Juno probe orbits Jupiter in a 53-day elliptical orbit, with a nadir of about 2,100 positions 3,400 kilometers above the skyscrapers of the planet.
The spacecraft built by Lockheed Martin is sound and all its instruments are ready for use, said Scott Bolton, chief investigator of the Juno mission at the Southwest Research Institute in San Antonio, during a presentation to the NASA Outer Planets Assessment Group last month ,
Juno's instruments have looked under Jupiter's clouds to examine the planet's internal weather patterns.
Juno data indicates that Jupiter has a blurred, poorly defined core that is much larger than expected. The discovery led scientists to suspect that an ancient collision between a young Jupiter and another giant protoplanete might explain Jupiter's fuzzy center.
Juno has also depicted Jupiter's Aurors and studied the lightning in the planet's hydrogen-rich atmosphere.
NASA has authorized Juno's mission to continue until July 2021, but Juno could continue to do so later in the 2020s. Juno is facing a 2020 review of the mission expansion.
Engineers fear that strong radiation around Jupiter could damage Juno's electronics on repeated passes through the planet's radiation belts. The spacecraft computer and other sensitive electronics are surrounded by a titanium compartment or vault to protect the components from radiation.
Officials say they have not seen any sign of radiation damage to the spacecraft.
Juno was supposed to be doing maneuvers in a lower orbit of 14 days around Jupiter after he arrived on the planet in 2016. However, a problem with the main engine of the aircraft prevented the orbit from changing.
The longer orbit of 53 days requires more time for Juno to provide the required scientific data of the mission. The Juno mission was originally scheduled to end in 2018 with a controlled destructive immersion in the Jupiter atmosphere.
One advantage of the 53-day longer orbit is that Juno receives a lower dose of radiation, which eliminates some of the concerns over radiation damage to spacecraft.
In its current orbit, the Juno spaceship would fly through Jupiter's shadow in November, robbing the orbiter of sunlight for its power-generating solar arrays. Ground crews plan to use the engines of the spacecraft's reaction control system on 30 September for a burn to easily adjust the trajectory around Jupiter to avoid the eclipse.
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