Credit: Eric NyquistGalileo saw four bright moons orbiting Jupiter in 1610. This dispelled the long-held belief that all celestial bodies revolve around the Earth. When scientists plan to send the Europa Clipper spacecraft in 2024 to study one of these moons, they may also find evidence that fundamentally changes our understanding of the solar systems.Europa, which is about the same size and sixth closest to Jupiter, is approximately the same size as ours. Scientists are almost certain that there is a liquid ocean beneath Europa's icy surface thanks to data from the Galileo space probelaunched 1989 and named in honor of the Italian astronomer. Astronomers think it may contain twice as much water than all the oceans on Earth.Europa has existed for over 4.5 billion years. However, its surface is only 60 million years old geologically. This suggests that it has been continuously resurfaced. It may have been resurfaced through shifting plate tectonics similar to Earth's. Europa orbits Jupiter around and its strong gravitational pull causes the moon to bend like a rubber ball. This heat is capable of keeping an ocean's liquid status. Hydrothermal energy from the moon's core may heat the ocean at its seafloor.NASA has deemed Europa the "most promising place in our Solar System to find current-day environments suitable to support life beyond Earth" because of these unique characteristics. Life cannot exist without water and energy. It needs essential chemicals such as hydrogen, carbon, oxygen. Europa appears to have checked the first two boxes but its composition is still a mystery. Europa's habitability will depend on whether all three ingredients are confirmed.Haje Korth is a Johns Hopkins Applied Physics Lab space physicist and deputy project scientist for Europa Clipper. His colleagues from NASA and the Jet Propulsion Lab in California are preparing to explore whether Europa may contain the necessary ingredients for life elsewhere in the vast ocean.They will launch the orbiter in late 2024 into the sky above Cape Canaveral. It will then begin its five-and a half-year journey to Europa. It will pass by Mars and Earth during that time, and use the gravity of both planets to propel itself 484 million mile toward Jupiter. It should arrive in 2030. One of the mission's scientists on the project, Kate Craft, warns that the long journey will bring with it even more challenges.She says, "The radiation from Jupiter's is really harsh." "Our instruments must be able to withstand that."Credit: Johns Hopkins UniversityThe Europa Clipper is roughly the same size as a basketball court and will be carrying ten instruments. Korth claims that getting all the gadgets to work in space will be a challenge.Two powerful cameras will map the surface of the moon in color and from different angles using two cameras. Spectrometers will examine the chemical composition of Europa's surface and the particles that orbit above it. A magnetometer can determine the depth and salinity in Europa's ocean.A thermal emission imaging system (UV spectrograph) and an ultraviolet spectrograph will be used to search for areas in which Europa's ocean has escaped onto the surface by plumes or eruptions. Scientists would be able analyze the composition of Europa’s ocean without ever having to touch its surface if they find such an area.Korth states, "These would represent the most pure samples of the ocean beneath." This is not a plume hunting mission, but we will certainly seize the opportunity."Clipper will spend three-and-a-half years orbiting Jupiter. He will flyby Europa approximately every two to three week from 16 miles away. The return observations will be sent back in less than a week. Scientists will examine the data and adjust them if they find something that interests them. The mission team currently has 45 flybys planned, but funding may allow for more.Although launch is still three years away, Craft has been part of numerous studies to determine the feasibility and logistics for a Europa Lander mission. If Europa Clipper finds that the moon is habitable, this would be the next logical step. A sky crane could transport a lander to Europa, much like the Mars Perseverance. It would house a cryobot that will drill through the icy shell to the ocean below.APL isn't just interested in Europa's subsurface water. The Lab announced in October 2020 that it would pitch NASA for the Enceladus Orbilander spacecraft, which is designed to orbit Saturn's sixth-largest Moon to search for signs and life within its ocean.You might find that Europa's interior is hot enough to ignite seafloor volcanoes.
