The Juno spacecraft flew by Io on April 9 at a distance of 106,000 kilometers its way to its 41st perijove. This is Juno's closest encounter of Io so far in its nearly six year mission, and the closest encounter with Io by any spacecraft since Galileo flew by in November 2002. The JunoCAM camera acquired these five images of Io during the encounter over a period of nearly an hour, with the first image being taken 8 minutes before closest approach and the last being taken 50 minutes after closest approach. The original pixel scales range from 72 kilometers per pixel for the upper left and upper center image to 91 kilometers per pixel in the lower right image. All images have been magnified by 5x to increase visibility of features using a simple nearest neighbor enlargement to reduce over-interpretation. All images are a combination of red, green, and blue filter framelets.
No apparent major surface changes or plumes can be seen in these images but even at 70 km/pixel, large-scale surface features can be seen across Io's northern trailing hemisphere. In the bottom left image, three mountains can be seen along the terminator, the boundary between Io's night and day sides, poking up on the dark side of the terminator.
Juno's next "Voyager-class" encounter with Io takes place on July 5 at a distance of 86,000 kilometers. Juno will perform several more encounters with Io over the next year and a half culminating in a pair of 1,500 km altitude flybys in late 2023 and early 2024.