NASA's mission to Europa, Jupiter's moon, will explore if life can exist under its icy shell

"There is very strong evidence that the ingredients for life exist on Europa. But we have to go there to find out," scientist Bonnie Buratti of NASA's Jet Propulsion Laboratory has said. "Just to emphasize: we're not a life-detection mission. We're just looking for the conditions for life," Buratti added.

Europa Clipper is the biggest spacecraft ever built by NASA for a planetary mission, measuring 100 feet (30.5 meters) in length, and about 58 feet (17.6 meters) in width. The probe weighs approximately 6,000 kg. The spacecraft, larger than a basketball court, will rely on solar power through its wide arrays to power instruments, and other systems on board.

NASA said it is aiming at 49 close flybys of Europa over three years.

NASA’s 1989 mission - The Galileo - had flown past Europa to measure its magnetic field, which confirmed a body of water beneath a layer of ice, estimated to be be 10-15 miles in thickness.

Findings from Clipper will be closely awaited as even though Europa is just a quarter of Earth's diameter, beneath its subsurface there is an ocean carrying twice as much water as there is on Earth's oceans.

"If we were to find that Europa is currently habitable, I think that’s paradigm changing," Amanda Nahm, deputy program scientist at NASA for the Europa Clipper mission has said.

Jupiter is the largest planet in the solar system with 95 officially recognized moons, with Europa being the fourth largest. While Europa gets only 4% of the solar radiation that Earth receives, its orbit is under the huge influence of Jupiter's strong gravitational pull, which produces heat.

Cracks on the surface where Europa's water meets the rocky mantle may reveal thermal vents, from where heat might be releasing energy. "They may be similar to thermal vents in the deep oceans of the Earth where primitive life exists and where life may have originated on the Earth," Buratti said.