Zurbuchen added that the missions were getting humans closer to understanding whether they were "indeed alone or not".
The moon Enceladus is just 502 kilometers (311 miles) in diameter and has an icy surface, a rocky interior and an ocean of liquid water sandwiched between the two. We know Europa and the moons around Jupiter existed 4 billion years ago so that is a lot more time for life to have emerged and start taking advantage of these energy sources. In laymen's terms, Enceladus could have hydrothermal vents that are similar to those found on Earth. Scientists think this kind of chemical reaction could have been the origin of life on Earth.
Microbes process both to obtain energy in a process known as methanogenesis.
While some ingredients for life were found on Enceladus, the scientists made clear that the discovery didn't confirm life on the planet, but merely confirmed favorable conditions.
The orbiting spacecraft Europa Clipper will investigate if Europa is habitable by studying the world's subsurface ocean. Only phosphorus and sulfur are missing. Cassini then sampled the plume's composition, and the scientists have determined that almost 98% of the gas in the plume is water, about 1% is hydrogen, and the rest is a mixture of other molecules including carbon dioxide, methane, and ammonia. This was detected during the spacecraft's final and deep dive amid the plume on October 28, 2015.More news: MPs back May's call for snap election
Meanwhile, Cassini's longstanding mission is soon coming to an end.
Using a spectrometer, the spacecraft determined that the plumes are 98% water and one percent hydrogen, with traces of molecules including ammonia, carbon dioxide and methane. Simple Earth organisms eat methane and excrete carbon dioxide, reports Sputnik. The INMS smells gases to ascertain their composition. INMS was created to sample the upper atmosphere of Saturn's moon Titan.
Researchers called its latest discovery a "capstone finding for the mission".
Writing in the journal Science, the U.S. team led by Dr Hunter Waite, from the Southwest Research Institute in San Antonio, Texas, concluded: "Our analysis supports the feasibility of methanogenesis as an energy-releasing process that can occur over a wide range of geochemical conditions plausible for Enceladus' ocean".
Older results have suggested that the hot water is intermingling with the rock underneath the sea.
Scientists said the moon appeared to have ample energy supplies to support life - roughly the equivalent of 300 pizzas per hour, according to Christopher Glein, a geochemist at the Southwest Research Institute in Texas. "But we do now have the last piece of evidence needed to demonstrate that life is possible there".