The instruments will hopefully reveal if there’s an underground ocean on the moon. Find out why scientists think Jupiter's moon Europa might have twice as much water as Earth! According to NASA, Pioneer 10 and 11 flew by Jupiter in the early 1970s, capturing images of Jupiter’s moons in detail. Voyager 1 and 2 followed in 1979, with images showing a surface brighter than Earth’s moon. The Galileo mission launched in 1989 and entered Jupiter’s orbit in 1995. “The information about Europa that Galileo sent was so intriguing that the mission was extended to make a total of 12 close flybys of the icy moon,” NASA said on its website. “Data from the mission included images of Europa at a range of scales, revealing new details about the surface and providing context for how those details related to the moon as a whole.” Scientists realized Jupiter’s magnetic field was disrupted around Europa. ARTICLE CONTINUES BELOW “Based on Europa’s icy composition, scientists think the most likely material to create this magnetic signature is a global ocean of salty water,” NASA said. “Europa Clipper will seek to confirm the presence of its ocean.” A few years ago, NASA used its Hubble Space Telescope to examine Europa, and scientists found what appeared to be a plume of water vapour, which increased curiosity. NASA's Hubble Space Telescope took direct ultraviolet images of the icy moon Europa transiting across the disk of Jupiter. Along with the $5 billion Europa Clipper mission, other missions to the moon are planned, including a Europa Lander mission concept to land on the surface to study composition and habitability. NASA’s Hubble Space Telescope has also revealed there may be an underground saltwater ocean on Ganymede — Jupiter’s largest moon.