A study published Monday suggests that the Galileo mission conducted 20 years ago may have flown through a water plume on Europa.
Data collected by Galileo in 1997 could be sent back to Earth in its entirety due to an antenna that failed to unfurl properly, according to the Washington Post.
Since 2012, scientists have suspected that water vapor plumes exist on the moon after the Hubble Space Telescope captured ultraviolet plume emissions at its South Pole.
Europa is one of 69 known moons of Jupiter and has been widely considered as a location where alien life might be discovered.
NASA plans to send its Europa Clipper mission in the 2020s, when it will investigate the possibility of water at or near the surface.
Read more on the discovery here.