NASA may send a mission to Jupiter's moon Europa to search for life. The Europa Clipper, still awaiting funding approval, will be the first dedicated mission to the watery moon.
Why Europa? It may be a more likely home to life than Mars.
"We generally focus down on Europa as the most promising in terms of potential habitability because of its relatively thick ice shell, an ocean that is in contact with rock below, and that it's probably geologically active today," Robert Pappalardo of NASA's Jet Propulsion Laboratory told the American Association for the Advancement of Science in Boston. "And we know there are oxidants on the surface of Europa."
Europa is covered in liquid oceans of water, which is blanketed by a thick layer of ice. Other large moons of Jupiter, like Ganymede and Callisto, also have liquid oceans under ice. The liquid remains unfrozen because of the pressure exerted on the oceans as the moons orbit Jupiter. This high pressure warms the water.
"On Earth, everywhere where there's liquid water, we find life," said Pappalardo. "The search for life in our solar system somewhat equates to the search for liquid water. When we ask the question where are the water worlds, we have to look to the outer solar system because there are oceans beneath the icy shells of the moons."
The Europa Clipper will cost about two billion dollars, and is still waiting for approval from NASA, reports The Guardian. The spacecraft will orbit Jupiter and do multiple fly-bys of the icy moon. This is similar to the Cassini probe's route, in which the probe orbited Saturn, studying the planet and its own moons.
The timetable for the probe won't put it near Jupiter for over a decade, if the funding is approved. The Europa Clipper could be ready to launch around 2021 and would take three to six years to reach Europa. It's unclear if NASA will go through with the mission, though. Currently, it seems more interested in Mars. The agency recently approved another rover to the Red Planet.
"Mars exploration is part of the bigger picture of human exploration," said Pappalardo. "However, part of NASA's mission is to go explore and that should include places that are an extremely high scientific priority. It really is one of the most profound questions we can ask: Is there life elsewhere in the solar system?"
