Washington: Europa - the sixth closest moon of Jupiter - is the most likely place in our solar system beyond Earth to have life, according to NASA.
As NASA scientists continue to search for signs of past life on Mars, they're also casting a hopeful eye toward finding life on Europa.
Most of what scientists know of Jupiter's moon Europa they have gleaned from a dozen or so close flybys from NASA's Voyager 2 spacecraft in 1979 and NASA's Galileo spacecraft in the mid-to-late 1990s, researchers said.
Even in these fleeting, paparazzi-like encounters, scientists have seen a fractured, ice-covered world with tantalising signs of a liquid water ocean under its surface.
Such an environment could potentially be a hospitable home for microbial life, NASA researchers said.
"If one day humans send a robotic lander to the surface of Europa, we need to know what to look for and what tools it should carry," said Robert Pappalardo, the study's lead author, based at NASA's Jet Propulsion Laboratory, Pasadena.
"There is still a lot of preparation that is needed before we could land on Europa, but studies like these will help us focus on the technologies required to get us there, and on the data needed to help us scout out possible landing locations.
"Europa is the most likely place in our solar system beyond Earth to have life today, and a landed mission would be the best way to search for signs of life," said Pappalardo.
The team found the most important questions clustered around composition: what makes up the reddish "freckles" and reddish cracks that stain the icy surface? What kind of chemistry is occurring there? Are there organic molecules, which are among the building blocks of life?
Additional priorities involved improving images of Europa - getting a look around at features on a human scale to provide context for the compositional measurements, researchers said.