Led by NASA, this mission must arrive near the largest planet in our solar system in 2030, after more than five years of travel.
Does life exist anywhere other than Earth in our solar system? To try to provide some answers to this fundamental question, the American space agency, NASA, must launch the Europa Clipper mission. Monday October 14. She will study Europa, one of the many moons of Jupiter, the largest planet in our solar system. Beneath its frozen surface, this star shelters an ocean of liquid water. It is considered by the scientific community as one of the most promising celestial bodies in our solar system for harboring life.
Franceinfo presents this American mission, which will partly work in a coordinated manner with the European Juice mission launched in April 2023.
A journey of five and a half years
Clipper is scheduled to depart aboard a SpaceX Falcon Heavy rocket, launched from the Kennedy Space Center (Florida, United States). The device should arrive near Jupiter in 2030, that is to say after five and a half years of journey. On its route, Clipper must pass close to the planet Mars to benefit from its gravitational force, as shown in this infographic from NASA.
In sight, Europa, one of Jupiter’s main moons
The largest planet in our solar system, Jupiter, has 95 official satellites, that is to say recognized by the International Astronomical Union. Among them, four are considered major: Io, Europa, Ganymede, Callisto, in order according to their distance from Jupiter. These stars are often called Galilean moons after their discovery in 1610 by the Italian Galileo.
Visually, Europe is distinguished by its striated surface, crossed by large lines like scratches.
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The surfaces of celestial bodies are often covered with craters, like our Moon, explains in this NASA video Erin Leonard, scientist involved in the Europa Clipper mission (1 min 08). Gold “there are very few craters” on the surface of Europa, underlines Shawn Brooks, another scientist on the mission. “This means something is happening to clear the craters. Like it happens on Earth, where we call it geology.”
Better understand its structure and its internal ocean
“All of Jupiter’s Galilean moons have a hidden ocean beneath their surface”remarks to franceinfo the geophysicist Olivier Grasset, specialist in our solar system. The particularity of that of Europe is that it is “probably in contact with the silicates, the rock mantle”completes the president of the space science advisory committee of the European Space Agency.
The composition of Europa is markedly different from that of the Earth and the Moon. Everything suggests that the outer surface is a frozen crust, under which is a liquid ocean, which is in contact with a thick rocky mantle, behind which is housed a core composed of rocks and metals.
On Earth, scientists have found kinds of chimneys, also called “black smokers” at the bottom of the oceans. These formations are created on reliefs created by the movement of tectonic plates. They spit out part of the Earth’s heat in the form of boiling water (up to 350°C) loaded with minerals, methane and hydrogen sulphide.
“It’s not the heat that allows wildlife to thrive nearby [de ces cheminées] but the chemistry of the sources”explains Claude-Bernard Lyon 1 University in this video published in May. In the darkness, chemosynthesis (instead of photosynthesis) developed, continues the commentary accompanying the images. Bacteria, which “draw their energy from the chemical compounds released by smokers”evolve in symbiosis with organisms. All these elements then become the foundations of a unique ecosystem, as shown in this Brut video.
Clearly, this activity (called hydrothermalism) makes it possible to generate, in a localized manner, life at the bottom of the oceans. The Europa Clipper mission will focus on characterizing the structure of Europa, by determining the thickness of its icy crust and the depth of the ocean (which is currently estimated at 100 kilometers). It is possible that formations similar to black smokers are found on the ocean floor of Europa, scientists suggest.
“At the bottom of the European ocean, we can imagine that we have the same conditions (pressure, temperature, chemistry) as at the bottom of the Earth’s ocean, where there is life.”
Olivier Grasset, planetologistat franceinfo
Some 50 flybys planned (the closest of which is only 25 km from its surface)
Weighing just over three tonnes with empty tanks, Clipper measures around 5 meters high and 30.5 meters long when its solar panels are deployed. In total, Clipper must carry out 50 flights over Europe to sift it with all its instruments (camera, spectrometer, magnetometer and radar), which will all be activated at the same time. NASA showed in a video a diagram showing the multiple flybys that the probe will carry out around Europe. The closest one will pass just 25 kilometers from the icy crust.
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Europa Clipper does not aim to find a possible form of life on Europa. She goes there to establish the most precise inventory possible, in particular to study possible geysers on its surface. “We are on geophysical observation, on standard chemistry”specifies Olivier Grasset.
Working in pairs with the European Juice mission
The European probe Juice, which left in April 2023 to explore the icy moons of Jupiter (including Europa) will collaborate with Europa Clipper for a time. The two devices will notably make it possible to better understand Jupiter’s magnetic field, which is up to twenty times more powerful than that of the Earth, and the way in which it interacts with its satellites, including Europa.
“Having two machines on site at the same time allows you to do science that would be unthinkable with just one.”
Olivier Grasset, planetologistat franceinfo
With two devices, it will be possible to take readings as if there were a transmitter and a receiver, the specialist further summarizes. “All of this is worked jointly between the teams [de Juice et d’Europa Clipper] with joint meetings of the order of twice a year, explains Oliver Grasset. This will allow optimization of scientific feedback.”
A crash planned on Ganymede
After its mission, Europa Clipper could end its journey by crashing into Ganymede, an important satellite of Jupiter, and the largest moon in our solar system. “This could be interesting because the impact would raise a cloud of ice which could then be observed by Juice”notes Olivier Grasset.
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Why not predict the crash of Clipper on Europa and possibly allow final remarkable discoveries? International planetary protection rules do not authorize such a maneuver. To the extent that Europa can potentially shelter a form of life, and that there are suspected points of communication between its surface and a hidden ocean, the Earthlings have decided not to contaminate it. On the other hand, as the European Space Agency explained for the Juice mission, Ganymede has a fairly thick ice crust, with no point of contact with the ocean below, which makes it possible for a manufacturing object to crash. land with less risk.