NASA’s Europa Clipper spacecraft will investigate whether Jupiter’s icy moons can support extraterrestrial life

The discovery of extraterrestrial life would be one of the most profound scientific and philosophical revelations humanity has ever made. However, such breakthroughs do not come easily. Our starting point is to first look for signs of habitability on other worlds, that is, signs of the possibility of life.

NASA is doing just that. On October 10th, the spacecraft will be launched towards Europa, a moon of Jupiter that holds twice as much water as all of Earth’s oceans combined. Europa’s ocean is 60 to 150 kilometers deep and hidden beneath an icy shell 15 to 25 kilometers thick. Marine evidence began to mount in the late 1990s.

The Europa Clipper mission will carry nine instruments designed to assess whether this oceanic world is habitable. As we know, a place can be habitable to life if three materials are available: liquid water, energy, and carbon-containing compounds called organic matter.

Despite more than five major mass extinctions, Earth has remained full of life for almost 4 billion years. Water and organic matter are abundant on our planet, and sunlight fuels photosynthesis in plants, allowing them to produce sugars that enter the animal kingdom through the species that eat them.

However, Europa’s salt ocean is pitch black below a few hundred meters, and photosynthesis cannot occur there. In 1977, when scientists probed deeper, nearly 2,500 meters deep into a volcanic hotspot on the Pacific ocean floor, they were surprised to find life thriving around the hydrothermal vents. It’s for a reason.

Life at that depth is supported not by photosynthesis but by chemosynthesis, which is how organisms obtain energy from chemical reactions. Sunlight is no longer a prerequisite for habitability.

The water in Europa’s ocean remains liquid due to frictional heating. This heating occurs because Europa is stretched and then relaxed as it interacts with Jupiter’s gravity during its orbit around the giant planet. For Europa’s ocean to be habitable, there must be a steady supply of raw materials for some chemical synthesis to take place.

If these components exist, they could be similar to those on Earth, seeping from hydrothermal vents on Europa’s rocky ocean floor or from its icy crust (or “ocean ceiling,” if you prefer). It may come from substances that cause The validity of these mechanisms is not yet known, and more data from various angles are needed.

There is growing evidence that plumes of matter are escaping from Europa’s surface into space. If this material comes from the ocean, measuring its composition could provide insight into the ocean’s habitability.

long road to europe

Scientists have been advocating for a mission to Europe since at least the 1990s. NASA’s Europa Orbiter was canceled in 2002, followed in 2005 by the ambitious Jupiter Icy Moon Orbiter (Jimo), which was scheduled to orbit the moons Europa, Ganymede, and Callisto.

In 2008, NASA and the European Space Agency (Esa) proposed the Europa Jupiter System Mission – Laplace (EJSM-Laplace), which aims to send orbiting satellites to Europa and Ganymede.

Both were canceled in 2011, but from the ashes rose Aether’s Jupiter Icy Satellite Orbiter (JUICE) and NASA’s Europa Clipper. Juice is scheduled to launch in April 2023 and arrive in July 2031, while Europa Clipper is scheduled to launch on October 10 and arrive in April 2030, as it will be launched with a more powerful rocket. , faster than juice. Both spacecraft will remain in the Jupiter system for three years at the same time, ultimately not far from the EJSM-Laplace mission.

Europa Clipper will not orbit Europa, but instead will cleverly orbit Jupiter in such a way that it will pass over Europa 44 times, eventually building a complete global scan of the moon. The spacecraft carries nine scientific instruments to provide a comprehensive understanding of the current state of Europa’s ocean, its geology, and activity.

NASA’s main missions are: “Europa Clipper’s main scientific goal is to determine whether there is a place for life beneath the surface of Jupiter’s icy moon Europa.”

During the flight, magnetic field instruments will help measure the depth and salinity of the ocean, mass spectrometers can “taste” the plume and see its composition, and ground-penetrating radar will tell if water is within the Earth’s crust. and helps understand whether substances are being exchanged. From the sea to the surface. Infrared equipment scans the surface for traces of organic matter that may be leaching, and also performs thermal imaging.

Planetary scientists have for decades pointed to oceanic worlds like Europa as potential habitats for life. Although Europa Clipper cannot directly detect life, it represents humanity’s first dedicated mission to study the ocean world and search for signs of habitability.

Any hint that life exists there could be followed by surface landers to probe deeper, and the surface observations collected by Clipper would be essential to planning that mission. . And as before, this only concerns life as we know it.

This article is republished from The Conversation under a Creative Commons license. Read the original article.