- By Jonathan Amos
- BBC Science Correspondent
Europa’s mission to Jupiter’s icy moons blasted off from Earth.
The JUICE satellite was launched into the sky aboard an Ariane-5 rocket from the Gauro spacecraft in French Guiana.
It’s second time lucky for the European Space Agency project after the Jupiter launch attempt was canceled due to weather.
The Jupiter IC Moons Explorer (JUS) is being sent to the Solar System’s largest planet to study its main moons, Callisto, Ganymede and Europa.
These icy crustal worlds are thought to retain vast reservoirs of liquid water.
Scientists are curious to know if moons can also support life.
This may sound like a fantasy. Jupiter is in the cooler, outer regions of the Solar System, far from the Sun and receives only about twenty-fifth of the light that falls on Earth.
But the gravitational pull exerted by a gas giant planet on its moons means it could have the energy and warmth to power simple ecosystems — similar to those around volcanic vents on Earth’s ocean floors.
“For Europa, a deep ocean is thought to lie 100 km deep beneath its icy crust,” said mission scientist Professor Emma Bunce of the University of Leicester, England.
“That ocean is 10 times deeper than the deepest ocean on Earth, and we think the ocean is in contact with the rocky floor. So that presents a scenario where there is mixing and some interesting chemistry,” the researcher told the BBC. news.
Arion didn’t have the guts to send the juice directly to its destination, at least not in a useful timeframe.
Instead, the rocket will send the spacecraft into orbit around the inner solar system. A series of flybys of Venus and Earth will carry the gravity towards its intended destination.
It is a journey of 6.6 billion km lasting 8.5 years. It is expected to arrive in the Jovian system in July 2031.
The icy moons Callisto, Ganymede and Europa were discovered by the Italian astronomer Galileo Galilei in 1610 using a recently invented telescope. He could see it returning as small dots around Jupiter. (He could also see the fourth body we now know as Io, a much smaller world covered in volcanoes).
The ice cloud has a diameter of 4,800 km to 5,300 km. To put this in context, Earth’s natural satellite is approximately 3,500 km.
Juice can study the moons at a distance. That is, it flies over their surfaces; It won’t go down. Ganymede – the largest moon in the Solar System – is the satellite’s final destination. It will go into orbit around this world in 2034 and complete its tour.
Radar is used to see the moons; Lidar, a laser measurement device, will be used to create 3D maps of their surfaces; Magnetometers probe their complex electrical and magnetic environments; and other sensors to collect data on particles orbiting the moons. Cameras, of course, send back countless images.
JUICE will not attempt to search for specific “biomarkers” or find alien fish in the deep ocean.
Its mission is to gather more information about potential habitat so that subsequent missions can directly address the life question.
Already scientists are thinking about how to land on one of Jupiter’s frozen moons and drill its crust for the water below.
In Earth’s Antarctica, researchers use heat to drill hundreds of meters through the ice to position submarines where the local sea freezes.
This is challenging work and would be an even bigger task on a Jovian moon where the ice crust is tens of kilometers thick.
Juice is not alone in its work.
The American space agency NASA is launching its own satellite called Clipper.
Although it will leave Earth after Jupiter, it will arrive next year, ahead of its European sibling. It has the advantage of a more powerful launch rocket.
Clipper will focus its investigations on Europa, but will do the same job.
“There is great complementarity and the teams are very keen to collaborate,” said European Space Agency Science Director Professor Carol Mundell.
“Of course, there will be a lot of data. But first, we need to make sure that our missions get to Jupiter and operate safely,” he told BBC News.