NASA’s Juno Spacecraft Will Perform Close Flyby of Jupiter’s Icy Moon Europa

An artist’s concept of the Juno spacecraft in orbit around Jupiter. Credit: NASA

As the Juno spacecraft makes a close approach to the moon Europa, it is expected to provide valuable science – and remarkable imagery – for[{” attribute=””>NASA’s upcoming Europa Clipper mission.

In less than three days, on Thursday, September 29, at 2:36 a.m. PDT (5:36 a.m. EDT), NASA’s Juno spacecraft will come within 222 miles (358 kilometers) of the surface of

Future missions could benefit greatly from this detailed information. One such mission is Europa Clipper, which is set to launch in 2024 to study the icy moon. “Europa is such an intriguing Jovian moon, it is the focus of its own future NASA mission,” said Juno Principal Investigator Scott Bolton of the Southwest Research Institute in San Antonio. “We’re happy to provide data that may help the Europa Clipper team with mission planning, as well as provide new scientific insights into this icy world.”

Jupiter’s Moon Europa JunoCam 2021

This image of Jupiter’s moon Europa was taken by the JunoCam imager aboard NASA’s Juno spacecraft on Oct. 16, 2021, from a distance of about 51,000 miles (82,000 kilometers). Credit: Image data: NASA/JPL-Caltech/SwRI/MSSS, Image processing: Andrea Luck CC BY

Europa is about 90% the size of Earth’s Moon, with an equatorial diameter of 1,940 miles (3,100 kilometers). Researchers believe a salty ocean lies below a miles-thick ice shell, sparking questions about potential conditions capable of supporting life underneath Europa’s surface.

Gravitational forces from the close flyby will modify Juno’s trajectory, reducing the time it takes to orbit Jupiter from 43 to 38 days. It will be the closest a NASA spacecraft has approached Europa in over 22 years, since Galileo came within 218 miles (351 kilometers) on January 3, 2000. Additionally, this flyby marks the second encounter with a Galilean moon during Juno’s extended mission. In June 2021, the mission explored Ganymede and plans include making close approaches of Io in 2023 and 2024.

Data collection on the spacecraft will begin an hour prior to closest approach, when the Juno is 51,820 miles (83,397 kilometers) from Europa.

“The relative velocity between spacecraft and moon will be 14.7 miles per second (23.6 kilometers per second), so we are screaming by pretty fast,” said John Bordi, Juno deputy mission manager at Juno’s Extended Mission

Juno’s extended mission includes flybys of the moons Ganymede, Europa, and Io. This graphic depicts the spacecraft’s orbits of Jupiter – labeled “PJ” for perijove, or point of closest approach to the planet – from its prime mission in gray to the 42 orbits of its extended mission in shades of blue and purple. Credit: NASA/JPL-Caltech/SwRI

Juno’s full suite of instruments and sensors will be activated for the Europa encounter. The spacecraft’s Jupiter Energetic-Particle Detector Instrument (JEDI) and its medium-gain (X-band) radio antenna will collect data on Europa’s ionosphere. Its Waves, Jovian Auroral Distributions Experiment (JADE), and Magnetometer (MAG) experiments will measure


This movie was generated using imagery collected on October 29, 2018, during Juno’s 16th perijove (the point at which an orbit comes closest to Jupiter’s center). Citizen scientists Gerald Eichstädt created this movie using data from the spacecraft’s JunoCam imager. Credit: Enhanced image by Gerald Eichstädt based on images provided courtesy of NASA/JPL-Caltech/SwRI/MSSS

Juno will be in Europa’s shadow when closest to the moon. However, Jupiter’s atmosphere will reflect enough sunlight for Juno’s visible-light imagers to collect data. The mission’s star camera (called the Stellar Reference Unit) will take a high-resolution black-and-white image of Europa’s surface. It was designed to take images of star fields and search for bright stars with known positions to help Juno get its bearings. Meanwhile, the Jovian Infrared Auroral Mapper (JIRAM) will attempt to capture infrared images of its surface.

Juno’s closeup views and data from its MWR instrument will inform the Europa Clipper mission, which will perform almost 50 flybys of the icy moon after it arrives at Europa in 2030. Europa Clipper will gather data on the moon’s atmosphere, surface, and interior. With this information, scientists expect to better understand Europa’s global subsurface ocean, the thickness of its ice crust, and possible plumes that may be venting subsurface water into space.

More About the Mission

NASA’s Jet Propulsion Laboratory (JPL), a division of Caltech in Pasadena, California, manages the Juno mission for the 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 at NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington. Lockheed Martin Space in Denver built and operates the spacecraft.

Leave a Reply

%d bloggers like this: