The next spacecraft to explore Jupiter, the JPL-managed Juno, arrived in polar orbit around the giant planet on July 4, 2016, and continues to return stunning images and scientific data. The European Space Agency plans to launch the JUICE (JUpiter ICy moons Explorer) in 2022 to arrive at Jupiter in 2029, make several flyby of several of the large moons, and finally enter orbit around Ganymede in 2032 for an in-depth study of that satellite. Under development at NASA, the Europa Clipper will launch in 2025 with arrival at Jupiter between 2026 and 2031, depending on the launch vehicle chosen. Once in orbit around Jupiter, Europa Clipper will make up to 45 flybys of its namesake satellite at altitudes as low as 16 miles to complete a comprehensive study. The two missions, JUICE and Europa Clipper, will conduct complementary investigations to greatly increase our knowledge of Jupiter and its satellites. Juno is the second spacecraft to orbit Jupiter, after the nuclear powered Galileo orbiter, which orbited from 1995 to 2003. [8] Unlike all earlier spacecraft sent to the outer planets, [8] Juno is powered by solar panels, commonly used by satellites orbiting Earth and working in the inner Solar System, whereas radioisotope thermoelectric generators are commonly used for missions to the outer Solar System and beyond. For Juno, however, the three largest solar panel wings ever deployed on a planetary probe (at the time of launching) play an integral role in stabilizing the spacecraft as well as generating power. [10] Naming [ edit ] These studies may provide answers to an age-old question known as the ‘energy crisis’ that asks why Jupiter’s upper atmosphere is much hotter than we can account for due to solar energy alone. Astronomers believe the auroral energy could somehow be transmitted from the poles to the equator, but the planet appears to spin too fast for this to be feasible. Juice will use three instruments to look at how Jupiter’s auroras and winds interact to understand how energy flows through Jupiter’s atmosphere.

As Jupiter rotates, a doughnut-shaped region of charged particles has built up around the planet, in what is one of the most intense radiation environments in the Solar System. Jupiter’s fast rotation creates a powerful natural particle accelerator that causes the particles to release radio waves. Juice will observe and characterise the charged particles and their radio emission using a suite of sensors and probes, both from inside the doughnut and from a distance, to capture how Jupiter works as an overall space plasma system. What’s more, measurements of the accelerated charged particles will improve our understanding of fundamental physics. Since arriving at Jupiter in July 2016, NASA’s Juno mission has been orbiting the gas giant every 53 days, capturing stunning high-resolution snapshots as it goes. Juice will complement Juno by taking a more global view, continuously watching Jupiter as a whole system to monitor how its ever-changing atmosphere and auroras evolve over time, from minutes to days to years. Exploring how Jupiter changes with time can reveal the processes that shape the physics and chemistry of this archetypal atmosphere, and could one day enable us to generate robust forecasts of the Jovian weather and climate.How does this all come together? Artist impression of 25 ‘hot Jupiters’ – gas giant exoplanets that look physically similar to Jupiter but orbit closer to their host stars Left: Trajectory of Galileo to reach Jupiter, and key events during the planetary orbital phase. Right: Galileo and its scientific instruments.

Juice’s entire arsenal of instrumentation will also tell us more about the Great Red Spot. Although it has been raging for hundreds of years, we can see from Earth that this huge storm is shrinking and starting to interact with other storms. To really understand this new phase of existence, Juice will look at how the storm changes over many years. Inside the Great Red Spot, gases are ‘cooked’ by ultraviolet rays from the Sun to form potentially unique molecules; Juice will use spectroscopy (looking at the wavelengths of light being absorbed and emitted by molecules inside the storm) to uncover the strange chemical processes taking place and the origins of those striking red colours.Galileo made the first close-up observations of an asteroid during a flyby of 12-mile long 951 Gaspra. Flying within 997 miles of the asteroid on Oct. 29, 1991, Galileo returned much science data and 150 photographs. A second flyby of the Earth took place on Dec. 8, 1992, with Galileo coming within 188 miles of its home planet. The spacecraft now had the required velocity to head toward Jupiter. Along the way, Galileo explored its second asteroid, flying within 1,500 miles of 35-mile long 243 on Aug. 28, 1993. The spacecraft made the surprising discovery that Ida had a tiny companion, the 1-mile wide satellite Dactyl orbiting about 90 miles away, the first known moon orbiting around an asteroid. Left: Illustration of Galileo in orbit around Jupiter. Right: Illustration by Ken Hodges of Galileo’s entry probe during its descent through Jupiter’s upper atmosphere. In total, Jupiter is surrounded by almost 80 moons, as well as rings of tiny dust particles. Whilst Saturn’s rings shine loud and clear, it wasn’t until 1979 that Jupiter’s more subtle ring system was discovered by astronomers. The age of these rings is still unknown, but various processes in Jupiter’s fierce environment destroy small dust particles, meaning that something must be constantly replenishing the rings if they are to live for very long. Some of the more significant findings not already mentioned above, Galileo fully mapped the global dynamics of Jupiter’s magnetosphere and made the first observations of ammonia clouds in the planet’s atmosphere. The previously discovered volcanic activity on Io may be 100 times more active than on Earth, and Io’s atmosphere, largely generated by that activity, may interact with Jupiter’s atmosphere. Galileo found evidence that Ganymede has a significant magnetic field, to date the only planetary satellite known to have one. The spacecraft discovered that Ganymede, Callisto, and Europa may all have a liquid saltwater subsurface layer and all three may have a tenuous atmosphere. Galileo found evidence supporting a theory that liquid oceans exist under Europa’s icy surface. “Galileo taught us so much about Jupiter but there is still much to be learned and for that we look with promise to future missions,” said JPL Director Charles Elachi.