NASA’s Juno skims the surface of Jupiter’s icy moon Europa

This next week will mark a scientifically valuable success for NASA’s Juno mission, as the groundbreaking spacecraft launched on the 29th as part of its expanded mission to explore the Jupiter system. A flyby this close to Europa’s surface will allow Juno to capture some of the highest-resolution images ever taken of the icy moon. For context, the last mission to probe Europe deeply was NASA’s Galileo spacecraft, which came within 351 kilometers (218 miles) of the surface on January 3, 2000.

High-resolution imagery isn’t the only goal, as Juno is expected to collect data on Europa’s ionosphere, its interior, surface composition, and the Moon’s interaction with Jupiter’s magnetosphere. All of this new data about Europa could be useful for future missions, including NASA’s Europa Clipper, which is currently scheduled to launch in October 2024 and arrive at Jupiter in April 2030.

“Europa is such an intriguing Jovian moon that it is the focus of its own future NASA mission,” said Dr. Scott Bolton of the Southwest Research Institute in San Antonio and principal investigator for the Juno mission. “We are excited to provide data that can help the Europa Clipper team with mission planning and provide new scientific insights into this frigid world.”

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In addition to collecting valuable scientific data during the close flyby, Juno’s trajectory will also be modified, reducing the number of days it takes the spacecraft to orbit Jupiter from 43 to 38. This flyby will also make Europa the second Galilean satellite to be explored by Juno during its enhanced mission, the first of which is Ganymede in June 2021, and is also scheduled to make close flybys of Io in 2023 and 2024.

While the most valuable images and data are undoubtedly generated at closest approach, Juno will begin collecting data about an hour earlier when the spacecraft is within 83,397 kilometers (51,820 miles) of the icy moon.

“The relative speed between the spacecraft and the moon will be 14.7 miles per second (23.6 kilometers per second), so we’re screaming by pretty quickly,” said Dr. John Bordi, Juno Deputy Mission Manager at NASA’s Jet Propulsion Laboratory in Pasadena. “All steps must run like clockwork to successfully capture our planned data, because shortly after the flyby is complete, the spacecraft must be realigned for our upcoming approach to Jupiter, which occurs just 7 ½ hours later.”

Juno is carrying a myriad of scientific instruments used in the exploration of Jupiter, and they will all be active during this close flyby of Europa to gather as much data as possible about the icy world. These include the Waves, Jovian Auroral Distributions Experiment (JADE) and Magnetometer (MAG) instruments looking for possible water plumes over Europa’s surface.

“We have the right gear to get the job done, but capturing a cloud takes a lot of luck,” said Dr. Bolton. “We have to be in the right place at exactly the right time, but if we’re that lucky, it’s a home run for sure.”

Juno’s Microwave Radiometer (MWR) instrument will collect data on the composition and temperature of Europa’s water-ice crust, the first time such data has been collected on Europa’s icy shell.

To top it off, Juno’s JunoCam will attempt to capture four visible-light images of Europa during the close flyby, with an expected resolution of 1 kilometer (0.6 miles) per pixel. Upon returning to Earth, the Juno science team will compare them to images from previous missions, looking for differences in Europa’s surface features that may have emerged over the past two decades. As mentioned, all of this new data will support the upcoming Europa Clipper mission, as this spacecraft is scheduled to make 50 flybys of Europa when it arrives at Jupiter in April 2030. Therefore, this close flyby of Europa by Juno can be seen as a test run for clippers.

What new knowledge will Juno teach us about the icy shell of this Europa and the moon at large? We’ll know soon enough, and that’s why we’re researching!

As always, keep doing science and keep looking up!

Featured image: Jupiter’s moon Europa, taken by the Juno spacecraft’s JunoCam on October 16, 2021 from a distance of approximately 82,000 kilometers (51,000 miles). (Credit: NASA/JPL-Caltech/Southwest Research Institute/Malin Space Science Systems)