Juice Mission: Voyage to Jupiter’s Moons | Knowledge & Environment | DW

It’s a special mission that will launch Thursday from the Korou Cosmodrome in French Guiana. The European Space Agency (ESA) is sending its ‘Jupiter Icy Moons Explorer’, Juice, to explore three of Jupiter’s icy moons.

Doesn’t that sound too exciting? Then you should consider that one of the objectives of the mission is “to characterize these moons both as planetary objects and as possible habitats”, according to the ESA. In other words, the mission is to find out whether life is possible on Ganymede, Europa or Callisto, or whether there was life on these moons in the past.

The Juice Project is a mission with many firsts. Launched on an Ariane 5 rocket, the probe will be the first to change orbit from another planet (Jupiter) to one of its moons. And it will be the first to orbit a moon other than our own.

The total cost of the mission is around 1.6 billion euros (1.7 billion US dollars). Juice will carry several high-tech systems, including the “most powerful remote sensing, geophysical and in situ payloads ever flown to the outer Solar System,” according to ESA.

Although the mission is European-led, it is the result of international collaboration. The NASA contributed one of the instruments, a UV spectrograph. The Japanese space agency JAXA has contributed the hardware for several instruments on board the spacecraft, while the Israel Space Agency ISA has contributed the hardware needed for a radio science experiment.

If all goes according to plan, Juice will reach Jupiter in July 2031 – a marathon travel time of eight years. Between July 2031 and November 2034 it will complete 35 flybys around the three moons. After that, the probe will enter Ganymede’s orbit, where it will remain until December 2035, collecting information.

Jupiter, the largest planet in our solar system

While the Juice mission only deals with three moons, Jupiter has a total of 95 moons with confirmed orbits.

Jupiter is the largest planet in our solar system and has twice the mass of all other planets combined. The NASA puts it that way: “If the earth were as big as a nickel [eine US-Fünf-Cent-Münze]Jupiter would be about the size of a basketball.”

Jupiter has a strong magnetic field. Part of the Juice mission is figuring out how it affects the icy moons that surround the planet.

Scientists already know that the magnetic field moves gases between Jupiter’s moons. Sulfur and oxygen released from volcanoes on the moon Io reach the three moons that Juice will explore. The researchers want to learn from Juice how this process works.

The moons at the heart of the Juice mission

Ganymede, Callisto and Europa were discovered by Italian astronomer Galileo Galilei in 1610. They are three of the four “Galilean moons” (the fourth is Io), and were the first objects in our solar system to orbit a body other than the Sun or Earth.

Ganymede, the main target of the Juice mission, is the only moon in our solar system that generates its own magnetic field. It is the largest moon in our solar system with a diameter of 5268 kilometers and a metallic core composed of a liquid containing iron. Its subsurface ocean is believed to contain more water than all of Earth’s oceans combined.

Callisto is the second largest moon of Jupiter. ESA scientists hope that by orbiting Callisto, Juice will be able to gather information about Jupiter’s environment in the planet’s early days. The moon is made of equal parts rock and ice and may have an underground liquid ocean more than 100 kilometers deep.

Europe is slightly smaller than that earth moon and possibly features vast subterranean oceans. It consists mainly of silicate rock and has a water ice crust. Juice scientists suspect that Europa may be releasing water vapor into space via geysers. One of the main goals of the mission is to find out if there are biosignatures and water accumulations – signs of life – on Europa.

The three moons are all named after characters from Greek mythology. In Greek mythology, Ganymede was a hero who was said to be the most handsome mortal on earth and was kidnapped by the gods to serve Zeus. Callisto was a nymph turned into a bear and later became the constellation Ursa Major. Europa was the mother of King Minos of Crete and the lover of Zeus, the Greek counterpart of the Roman god Jupiter.

The difficult environment of Jupiter

The Juice spacecraft will operate under extreme conditions. The environment around Jupiter and its moons is one of the most radiant in our solar system. The temperature around the gas planet is a chilly -230 degrees Celsius (-382 degrees Fahrenheit), a stark contrast to the sweltering 250 degrees Celsius Juice faces during its Venus flyby en route to Jupiter.

The gravity-assisted flyby, a small detour of 300 million kilometers, will put the probe on course for its arrival at Jupiter in 2031.

The researchers behind Juice hope the mission will answer a number of questions about Jupiter’s atmosphere, Jupiter’s magnetic field, and how these factors interact to affect the planet’s moons.

It is hoped that the answers to these questions will help scientists better understand the basic physics of planetary environments and eventually determine if life would be possible on one of Jupiter’s moons.