How scientists might find life on Saturn's moons while avoiding the most difficult part

What evidence is Enceladus launching into space?

NASA's Cassini probe captured this close-up of one of Saturn's moons, Enceladus, an icy world, in 2010. Image credit: NASA/JPL/Space Science Institute.

Without having to set down a spacecraft on one of Saturn's 83 moons, scientists think they might be able to determine whether there are microscopic aliens there.

Planetary scientists looking for life outside of the blue marble have become fascinated by Enceladus, which is about 800 million miles from Earth and 25 times smaller. The ocean on the Saturn moon spews geyser-like plumes into space that contain small particles of gas and water. The halo that is produced by that continuous spray helps to form one of Saturn's rings.

Scientists have urged NASA to support upcoming space flight missions and asked for funding to make landings on the planet's surface. One such proposal, the Enceladus Orbilander created by the Johns Hopkins Applied Physics Laboratory in Maryland, would study it over a 1.5-year period beginning in the 2050s from the moon's surface as well as from space. According to The Planetary Society, a nonprofit organization devoted to advancing space science, the complicated mission would cost approximately $2.5 billion.

Now, a research team led by the University of Arizona has outlined a proposal for a fairly simple method, contending that all scientists would require to ascertain whether microbes exist beneath Enceladus' icy shell is an orbiting space probe. This December, The Planetary Science Journal published the study.

The lead author, Antonin Affholder, said in a statement: "Our research shows that if a biosphere is present in Enceladus' ocean, signs of its existence could be picked up in plume material without the need to land or drill. However, such a mission would require an orbiter to fly through the plume several times to collect lots of oceanic material.

The Cassini spacecraft of NASA captured this mosaic image of Enceladus in 2008. Image Credit: NASA / JPL / Space Science Institute

How many times, exactly? The paper estimates that there have been over 100 flybys.

The research team is focusing on the most amount of organic material that could be present without life, rather than trying to determine how much organic material would have to be found to prove that life is there, in order to find the presence of alien life.

Enceladus wasn't much more than a tiny snowball when it was first observed by NASA's Voyager 1 probe in 1980. Recently, scientists have discovered that beneath the thick layer of ice covering the moon, there is a warm saltwater ocean that emits methane, a gas that is typically produced by bacteria and other microorganisms on Earth. NASA's crewless Cassini spacecraft traveled through Saturn's rings and moons between 2005 and 2017, providing a wealth of new data.

A group from the University of Arizona and Université Paris Sciences et Lettres in Paris determined last year that the moon's methane burps may be caused by microbial life on Enceladus.

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