The Clipper Probe Ready for a Six-Year Journey to Reach the Ocean of Water in Space

If no unexpected events occur, on October 11, one of the Falcon rockets will carry an important payload into space: a probe named Europa Clipper, which is set to visit one of the most significant moons in the solar system. Europa, a moon orbiting Jupiter, is believed to harbor a vast ocean of liquid water beneath its thick ice layer, and researchers think that beyond Earth, the greatest likelihood of life exists in the expansive oceans of this moon. When Galileo first looked at the sky through his small telescope, he was thrilled to see a world different from the common beliefs of his time. Jupiter was among the first sights he observed with the telescope. Galileo saw four bright points around it that orbited the giant planet over consecutive nights. This was one of the first observational evidences confirming that not everything in the universe revolves around the Earth. These four bright points, known as the Galilean moons, are four of over 95 moons discovered around Jupiter so far. The four moons, in order from the planet outward, are Io, Europa, Ganymede, and Callisto, each representing a remarkable world around our solar system's giant planet. Io has the most active eruptions observed in our solar system, Europa hosts a vast ocean of liquid water beneath a massive ice layer, Ganymede is the only moon in the solar system with a magnetic field, and Callisto, one of the most stable moons in this family, is considered a potential site for establishing a base in the future for exploring these worlds. In the early decades of telescopic exploration of the sky, we had little information about these amazing worlds. The beginning of acquiring more precise information about them started with the space age, particularly with the Pioneer and Voyager missions in the 1970s. The data these spacecraft collected while passing by the Jupiter family changed our view of these worlds. However, more time was needed to deepen our understanding of these diverse worlds. The Galileo space mission, which began its journey to Jupiter in 1989 aboard the Atlantis space shuttle, reached the planet six years later in 1995, revolutionizing our understanding of this amazing world and the evolution of the solar system. One of the most important achievements of this mission was the collection of data that reinforced the hypothesis of an ocean of liquid water beneath Europa's icy crust. The data from this mission increased the likelihood of some form of life existing in Europa and other large moons of Jupiter, prompting mission engineers to deliberately guide Galileo into Jupiter's thick atmosphere at the end of its mission to prevent any potential damage to these moons. Since then, with new information obtained and particularly models of the subsurface heat-generating structure of Europa, primarily created by Jupiter's tidal forces, the hypothesis of the possibility of life forming and even persisting to this day in this distant world has been proposed. In recent years, Europa, alongside Enceladus, a moon of Saturn (which also has a subsurface ocean of liquid water beneath an icy crust), has become one of the best candidates for hosting life in the solar system after Earth. However, the path to Europa is not straightforward. Many scientists hoped to send a lander on the first attempt to directly investigate this moon, capable of drilling a hole in its icy crust to send tiny robots to explore its oceanic world. However, Europa is a hostile environment. Europa's orbit around Jupiter passes through the region of high-energy radiation surrounding Jupiter, and any mission heading to this moon or even its orbit cannot operate for more than a few days under bombardment by high-energy particles with current technology, as its electronic devices would fail. On the other hand, our understanding of Europa's surface is still insufficient to determine where the best opportunity for a successful investigation lies, even if we were to risk sending a lander mission. The existing capabilities, alongside scientists' aspirations, ultimately led to the birth of a mission named Clipper; a mission that is among the last designed by the late Firouz Naderi and is now on the verge of its historic journey. To survive the problem of Jupiter's high-energy radiation field, Clipper will not head directly to the moon but will take a long path that will last six years, arriving at Jupiter in 2030. This spacecraft will pass by Earth and Venus several times to gain gravitational assistance for the energy needed to reach Jupiter. After reaching its destination, Clipper will enter an elongated orbit around Jupiter. However, this orbit is designed so that during the mission, the probe will pass close to Europa 45 times, at distances ranging from 25 to 100 kilometers from Europa's surface, allowing it to provide scientists with a relatively complete image of the entire moon. During this period, the spacecraft's instruments will examine the surface structure, surface materials, ice depth, and conduct detailed remote sensing studies of the ocean beneath the surface of this moon, providing scientists with a fresh and revolutionary view of Europa that could pave the way for understanding and formulating future missions to Europa. Simultaneously with Clipper, another mission by the European Union named JUICE, which has already begun its journey, will reach Jupiter. If both missions are successful, the 2030s should be regarded as a decade of revolution in understanding Jupiter and the family of the giant gas planet in the solar system; a time when this data will not only transform our understanding of the evolution of the solar system and the family around the giant gas planets but may also take significant steps toward answering the question of whether life exists somewhere in the neighborhood of our old home. Clipper carries with it a plaque to Jupiter. Part of this plaque features the poem 'In Praise of Mystery: A Poem for Europa' by Ada Limón, as well as an image of Ron Greeley, a pioneer in planetary science, and a chip containing the names of over two and a half million people. On the other side of this plaque, an audio wave of the pronunciation of the word 'water' in various languages is inscribed to remind us of the primary goal of this mission and its journey to the distant watery world of Europa.