Europa’s orbit is an ellipse, and the satellite’s shape is affected by Jupiter’s gravity, deforming as it approaches Jupiter.
This change in shape creates friction within Europa, generating enormous amounts of heat in a mechanism known as tidal heating, which melts some of the ice and forms a vast inner ocean beneath the moon’s thick icy crust.
Europa’s inner ocean is salty and is estimated to be about 100 kilometers deep on average, and the total volume of water is twice the volume of all Earth’s oceans, even though this moon is much smaller than our planet.
In addition, inner oceans are thought to exist on Jupiter’s moons Ganymede and Callisto and Saturn’s moons Titan and Enceladus.
Liquid water is essential for life as we know it, which is why ocean worlds are at the forefront of the search for extraterrestrial life.
under the sea (ice)
The autonomous underwater exploration robots envisioned by SWIM are extremely small. Their wedge-shaped bodies are about 12 cm long. A device called a cryobot will move robots under the moons’ thick icy shells, using nuclear energy to melt the ice. The idea is to put about forty of the robots in the cold robot and have them penetrate the thick ice crust over several years.
There are benefits to sending so many exploration robots. The first is that they can explore a wider area. The other reason is that it is conceivable to work in teams, so that multiple robots can explore the same area in overlapping directions, reducing errors in monitoring data.
Each robot will be equipped with sensors to measure the temperature, pressure, acidity, electrical conductivity and chemical composition of the water it explores. All of these sensors will be mounted on a chip that is only a few square millimeters in size.
“People might ask, why is NASA developing an underwater robot for space exploration?” says Ethan Schaller, project leader at NASA’s Jet Propulsion Laboratory, explaining the motivation behind SWIM. “Because there are places in the solar system that we want to go to look for life, and we think that life requires liquid water.”
This story originally appeared on Wired Japan It was translated from Japanese.
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