Saturn's moon Titan could be hiding a deep ocean beneath a thick crust of ice, according to new research.
Radar images from the Cassini-Huygens mission support the idea that there's a huge pool of liquid water beneath the surface of the moon.
The Cassini spacecraft was sent into orbit around Saturn in 2004 before sending the Huygens probe onto the surface of Titan to get a closer look.
Now experts want to send an even better probe to Titan to test their theories.
Space expert Professor John Zarnecki, who was not part of the study, said the latest data was very exciting.
"Titan is 50% water-ice. If it is liquid, as this paper is implying some of it is, it looks as though we've got at least two of the things to initiate the chemistry that leads to life.
"We've got to go back again with balloons and rovers and really understand this place."
Titan is the second largest moon in the Solar System, behind Jupiter's Ganymede satellite.
Only three other Solar System objects are suspected of having deep oceans: Ganymede, Callisto and Europa.