NASA Wants to Explore the Icy Moons of Jupiter and Saturn With Autonomous Robots

Europa's orbit is an ellipse, and the satellite's shape is affected by Jupiter's gravity, becoming deformed when it passes closer to Jupiter. This change in shape creates friction inside Europa, generating enormous amounts of heat in a mechanism known as tidal heating, which melts some of the ice and forms a vast internal ocean beneath the moon's thick ice shell. Europa's internal ocean is salty and is estimated to be about 100 kilometers deep on average, with a total volume of water twice that of all Earth's oceans, despite this moon being considerably smaller than our planet. In addition, it is believed that internal oceans 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 the ocean worlds are at the forefront of the search for extraterrestrial life.