NASA's Juno probe will make its closest flyby of Jupiter's moon Io on Saturday, December 30, the closest flyby of Io by any man-made probe in more than 20 years. The flyby, about 930 miles (1,500 kilometers) from the surface of the most volcanic world in the solar system, is expected to produce a wealth of data from Juno's instruments. The orbiter has flown by Jupiter 56 times and recorded close encounters with three of the gas giant's four largest moons.
This image revealing the north polar region of Ganymede was taken by NASA's Juno spacecraft on October 15. The three peaks visible near the day-night boundary in the upper half of the image were first observed by Juno's cameras. Image source: Image data: NASA/JPL-Caltech/SwRI/MSSS, Image processing: TedStryk
"By combining data from this flyby with our previous observations, the Juno science team is studying how Europa's volcanoes change," said Juno principal investigator Scott Bolton of the Southwest Research Institute in San Antonio, Texas. "We are studying the frequency of their eruptions, their brightness and heat, changes in the shape of lava flows, and how Europa's activity relates to the flow of charged particles in Jupiter's magnetosphere."
Europa's second ultra-close flyby is planned for February 3, 2024, when Juno will once again approach a range of approximately 930 miles (approximately 1,500 kilometers) from Europa's surface.
The spacecraft has been monitoring Europa's volcanic activity from a distance of about 6,830 miles (11,000 kilometers) to more than 62,100 miles (100,000 kilometers) and provided the first views of its north and south poles. The spacecraft also made close flybys of Jupiter's icy moons Europa and Ganymede.
"Through our two close flybys in December and February, Juno will investigate the source of Io's massive volcanic activity, the presence of a magma ocean beneath its crust, and the importance of tidal forces from Jupiter that are mercilessly squeezing the tortured moon," Bolton said.
The solar-powered spacecraft will also explore the ring system that houses the gas giant's inner moons.
All three cameras on Juno will be in working order during the Io flyby. The Europa Infrared Auroral Imager (JIRAM), which takes infrared images, will collect heat from the volcanoes and craters covering the moon's surface. The mission's Stellar Reference Device, a navigation star camera that also provides valuable scientific information, will obtain the highest-resolution images of the lunar surface to date. The JunoCam camera will capture visible light color images.
JunoCam is installed on the spacecraft for public participation and is designed to operate for up to eight flybys of Jupiter. The upcoming Io flyby will be Juno's 57th orbit around Jupiter, where the spacecraft and cameras have endured some of the harshest radiation environments in the solar system.
"Over the past few orbits, the cumulative effect of all the radiation has begun to show up on the Juno camera," said Ed Hirst, Juno project manager at NASA's Jet Propulsion Laboratory (JPL) in Southern California. "Photos from the last flyby showed a reduction in the dynamic range of the imager and the appearance of 'streak' noise. Our engineering team has been working on solutions to mitigate radiation damage and allow the imager to continue working."
After months of study and evaluation, the Juno team has adjusted the spacecraft's future planned trajectory, adding seven new long-distance flybys of Io (18 in total) to the expanded mission plan. After the close flyby of Io on February 3, the spacecraft will fly by Io every other orbit, with each orbit gradually increasing in distance: the first flyby will be about 10,250 miles (about 16,500 kilometers), and the final flyby will be about 71,450 miles (about 115,000 kilometers).
During the December 30 flyby, Io's gravitational pull on Juno will shorten the spacecraft's orbit around Jupiter from 38 days to 35 days. After its flyby of Jupiter on February 3, Juno's orbit will be reduced to 33 days.
After that, Juno's new orbit will cause Jupiter to block the sun for about five minutes when the orbiter is closest to Jupiter, a period known as perijove. Although this will be the first time the solar-powered spacecraft has encountered darkness since it flew by Earth in October 2013, the duration is too short to affect its overall operation. In addition to the near-lunar eclipse on February 3, the spacecraft will encounter such an eclipse every time it makes a close flyby of Jupiter between now and the remainder of the extended mission, which ends in late 2025.
Starting in April 2024, Juno will conduct a series of occultation experiments, using Juno's gravity science experiments to detect the composition of Jupiter's upper atmosphere, thereby providing key information about the shape and internal structure of Jupiter.
JPL, a division of the California Institute of Technology in Pasadena, California, manages the Juno mission for principal investigator Scott J. Bolton of the Southwest Research Institute in San Antonio. Juno is part of NASA's New Frontiers program, which is managed by NASA's Marshall Space Flight Center in Huntsville, Alabama, for the Science Mission Directorate in Washington. Lockheed Martin Aerospace in Denver builds and operates the probe.
Compiled source: ScitechDaily