“The big question is whether there can be habitable environments” on moons

“The big question is whether there can be habitable environments” on the moons of Jupiter, explained Thursday April 13 on franceinfo Olivier Witasse, scientific manager of the Juice mission (JUpiter ICy moon Explorer) at the European Space Agency. The European Juice probe will cross part of the solar system to explore Jupiter and its satellites. It will take eight years before arriving on Jupiter.

franceinfo: The probe will travel two billion kilometers to arrive at Jupiter, i.e. three times the distance between Earth and Jupiter. For what ?

Olivier Witasse: In space, we rarely go in a straight line. The problem with Juice is that it is an extremely heavy satellite, it weighs six tons, and you cannot send a satellite of this mass directly to Jupiter. We will therefore make it do several laps around the Sun, make it go towards the Earth, towards Venus. Each time we go to a planet we gain a little bit of energy and speed. That’s why it takes eight years to get to Jupiter.

>> Space: we explain the European Space Agency’s Juice mission, which is going to explore Jupiter and its icy moons

The probe will be confronted with extreme temperatures, up to 250° and down to -250°. How can you be sure it arrives intact?

We have been working with manufacturers since the beginning of 2015. We gave them our specifications, it must also resist Jupiter’s radiation. The manufacturers answered yes and we are building a satellite that can withstand these temperatures. They made a working satellite design, we tested it.

What will happen once there?

Six months before its arrival on Jupiter, we will turn on all the instruments of the probe to start taking measurements, to see that everything is fine. Then there will be the insertion into orbit around Jupiter. As the probe arrives with a certain speed, it must be decelerated so that the speed decreases. To do this, a motor is turned on the probe which allows the speed to be reduced and the probe to be captured by Jupiter’s gravity field. This will take a few tens of minutes. Then we will be in orbit around Jupiter and for four years we will fly over Jupiter and its icy moons regularly. At the end of the mission, we will go into orbit around Ganymede, which is the largest moon in the solar system. The end of the mission will end with an impact.

What is special about these moons?

They are called icy moons because they are covered in ice. What is fascinating is that several kilometers below the surface there is more liquid water than on Earth. On Ganymede, it is believed that there is an ocean more than 100 kilometers deep and that it contains perhaps five to six times more liquid water than on our own Earth. We’re sending Juice over there to find out more. The big question is whether there can be habitable environments inside these moons. To find out, we have several detection elements including a magnetometer which allows us to study the magnetic fields with very high precision. These oceans have magnetic marks that can be detected from orbit.

Was there life on Jupiter?

It’s a big question. Currently, Jupiter and its icy moons are thought to be the most interesting for looking for traces of life. It could also be moons around Saturn. But we focus on Jupiter and its moon Europa is the most interesting for the search for life. But we’re going to study all the moons of Jupiter.

What about the power consumption of the probe?

We are far from the Sun, so we have 25 times less solar flux on Jupiter. So, we made solar panels that are 25m2. The power generated is that of a hair dryer or a microwave oven.