This composite image of the Jovian moon Io was generated using data collected by the JunoCam imager aboard NASA's Juno spacecraft during four separate flybys. The resolution of the images gets progressively better as the distance between spacecraft and moon decreases with each flyby.

The image of the moon on the far left has a resolution 44 miles (71 kilometers) per pixel. It was taken on April 9, 2022, during Juno's 41st orbit of Jupiter (perijove 41, or PJ41), when the spacecraft flew past Io at a distance of about 66,000 miles (106,000 kilometers). Note the gray, roughly triangular patch at the terminator near the moon's center. Citizen scientist Björn Jónsson created this image using data from JunoCam.

The center-left image was acquired on July 5, 2022, during Juno's 43rd orbit of Jupiter (PJ43) at a distance of 53,000 miles (86,000 kilometers). The resolution in this image has improved to 36 miles (58 kilometers) per pixel. In this view, more detail of the gray patch is seen (from a different perspective). Citizen scientist Jason Perry created this image using data from JunoCam.

By the time the center-right image of Io was taken on Dec. 14, 2022, (PJ47), the distance between spacecraft and moon had decreased to 40,000 miles (64,000 kilometers), which increased the resolution to 27 miles (43 kilometers) per pixel. Here, the gray triangle appears as three distinct volcanoes with the central vents visible as dark spots in their centers. Characteristics of other nearby volcanoes also begin to stand out. Citizen scientist Mike Ravine created this image using data from JunoCam.

The far-right image, taken during Juno's 49th flyby (PJ49) on March 1, 2023, shows that the spacecraft again approached the moon from a changed perspective, allowing different territory on Io's surface to be viewed. The triplet of volcanoes that make up the gray triangular patch are visible near the top of the image, and more detail of the volcanic terrain can be made out. The altitude at the time of closest approach was about 32,000 miles (51,500 kilometers), allowing resolution to increase to 22 miles (35 kilometers) per pixel. Citizen scientist Kevin M. Gill created this image using data from JunoCam.

More information about Juno is online at https://www.nasa.gov/juno and https://missionjuno.swri.edu.

NASA's Jet Propulsion Laboratory manages the Juno mission for the principal investigator, Scott Bolton, of 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 NASA's Science Mission Directorate. Lockheed Martin Space Systems, Denver, built the spacecraft. Caltech in Pasadena, California, manages JPL for NASA.