NASA’s Juno Spacecraft Will Make Closest Flyby of Jupiter’s Moon Io Since 1999
NASA’s Juno spacecraft is set to make the closest flyby of Jupiter’s moon Io that any spacecraft has made in over 20 years. On Saturday, December 30, Juno is expected to come within roughly 930 miles (1,500 kilometers) from the surface of the most volcanic world in our solar system.
This pass is expected to allow Juno’s instruments to generate a firehose of data and study how Io’s volcanoes vary. The spacecraft will also be performing a second ultra-close flyby of Io on February 3, 2024, in which Juno will again come within about 930 miles (1,500 kilometers) of the surface.
According to Juno’s principal investigator, Scott Bolton of the Southwest Research Institute in San Antonio, Texas, the spacecraft has monitored Io’s volcanic activity from various distances and provided the first views of the moon’s north and south poles. In addition to Io, Juno has also performed close flybys of Jupiter’s icy moons Ganymede and Europa.
Bolton stated, “With our pair of close flybys in December and February, Juno will investigate the source of Io’s massive volcanic activity, whether a magma ocean exists underneath its crust, and the importance of tidal forces from Jupiter, which are relentlessly squeezing this tortured moon.”
The flyby of Io will mark Juno’s 57th orbit around Jupiter. The spacecraft has three cameras which will be active during the Io flyby. The Jovian Infrared Auroral Mapper (JIRAM), the mission’s Stellar Reference Unit, and the JunoCam imager will all be collecting data from the flyby.
Juno was designed to operate for up to eight flybys of Jupiter and as it enters the third year of its extended mission to investigate the origin of Jupiter, the spacecraft will increase its frequency of encounters with Jupiter’s moons. The Juno team has adjusted the spacecraft’s planned future trajectory to add seven new distant Io flybys to the extended mission plan, with each orbit growing progressively more distant.
After its close Io pass on February 3, 2024, the spacecraft will fly by Io every other orbit, with each orbit growing progressively more distant. This will be the case until the spacecraft’s extended mission ends in late 2025.
The cumulative effects of radiation exposure have started to take a toll on Juno’s cameras, however, with the engineering team working on solutions to keep them operational.
Juno is a part of NASA’s New Frontiers Program and is managed at NASA’s Marshall Space Flight Center in Huntsville, Alabama by the Science Mission Directorate in Washington.