Several images have been returned to Earth from NASA’s Juno spacecraft showing the beauty of the giant planet Jupiter and its tiny lava-covered moon Io.
When the solar-powered spacecraft completed its 47th close pass (perijove) from Jupiter on December 14, it attempted to return its science data to NASA, but the downlink was disrupted.
After an initial return of just one image – of its volcanic moon Io – the rest of the raw data for Io and Jupiter appeared online on 4 January. Since then, a team of image editors – all dedicated volunteer “citizen scientists” – have been posting a bunch of spectacular finished images online.
The delay was caused by a radiation-intensive part of Jupiter’s magnetosphere, according to NASA. Mission controllers at NASA’s Jet Propulsion Laboratory restarted the on-board computer and put the spacecraft into safe mode.
Juno’s images of I0 — the most volcanic body in the Solar System — were taken while Juno was 40,000 miles away. The moon is believed to have an underground ocean of magma. Just before Juno came close to Io, a burst of volcanic activity began.
Io is in a constant gravitational tug of war with Jupiter and the other large moons, so much so that it actually changes shape during its 42-hour orbit. It is believed that constant stretching and squeezing causes frictional “tidal heating.”
This flyby of Io was Juno’s first of nine over the next few years, two of which will be from just 1,500 kilometers away.
“The team is very excited that Juno’s extended mission includes the study of Jupiter’s moons. With each close flyby, we have been able to obtain a wealth of new information,” said Juno principal investigator Scott Bolton of the Southwest Research Institute in San Antonio . “Juno sensors are designed to study Jupiter, but we’ve been excited by how well they can do double duty by observing Jupiter’s moons.”
Juno launched in 2011 and arrived at Jupiter in 2016. It has since completed 47 close flybys of the planet’s polar regions, with the last on December 15, 2022. It included the first of nine flybys of Io — the most volcanic body in the Solar System — two of them from only 930 miles/1500 kilometers away.
The two superclose flybys will take place on December 30, 2023 and February 3, 2024. During them, Juno will study Io’s volcanoes and how volcanic eruptions interact with Jupiter’s powerful magnetosphere and auroras.
The spacecraft is in a highly elliptical orbit that sees it come close to Jupiter’s moons and the planet’s polar regions only once every five or six weeks, which is when it turns on its two-megapixel camera.
Juno’s mission is to study Jupiter’s composition, magnetic field and magnetosphere, to measure water in the atmosphere and winds. It has discovered how Jupiter’s atmosphere works and revealed the complexity and asymmetry of its magnetic field.
Juno has also revealed the size of Jupiter’s “Great Red Spot”, which stretches over 200 miles/350 kilometers. The solar system’s largest storm is located 22º south of Jupiter’s equator and has been raging since at least 1830. Its diameter makes it almost twice the size of Earth.
The spacecraft also studied Jupiter’s “Great Blue Spot,” an isolated patch of intense magnetic field near the planet’s equator.
In October 2021, new findings from Juno provided the first 3D look at how the giant planet’s “beautiful and violent atmosphere” operates beneath the uppermost layers of clouds.
It has also completed close flybys of Jupiter’s moons Europa and Ganymede, sending back a total of over three terabits of scientific data so far.
However, the spacecraft is now in an exciting extended mission. After completing in November 2021 its standard 37-orbit five-year survey of Jupiter, Juno was given a new lifetime through 2025.
Although it may get a further extension, if not then the spaceship’s 76th and last perijove will be September 15, 2025, when it will perform a “death dive” into the gas giant. That would prevent it from accidentally crashing into, and possibly contaminating, one of Jupiter’s moons.
Juno is the ninth spacecraft to image Jupiter, the others being Pioneer 10 and Pioneer 11, Voyager 1 and Voyager 2, Galileo Orbiter and Galileo Probe, Ulysses and Cassini.
Juno’s next flyby of Jupiter, perijove 48, takes place on 22 January 2023.
Wishing you clear skies and big eyes.