Nasa scientists are planning a mission that could look for life on Europa, a moon of Jupiter that is covered in vast oceans of water under a thick layer of ice.
A probe could be ready in 2021, but it could take almost six years to get there depending on the type of rocket used. The Europa Clipper would be the first dedicated mission to the Jupiter moon, and would first need funding approval from Nasa.
BBC News reports that the project is set to cost $2 billion.
“On Earth, everywhere where there’s liquid water, we find life,” said Robert Pappalardo, a senior research scientist at Nasa’s jet propulsion laboratory in California, who led the design of the Europa Clipper.
“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.”
With 67 confirmed moons, Io, Ganymede, Callisto and Europa are Jupiter’s biggest moons . While they are too far from the sun to gain much heat from it, the oceans that lay beneath their layers of ice are warmed up as they orbit the planet.
Speaking at the annual meeting of the American Association for the Advancement of Science in Boston, Pappalardo said:
“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.”
Europa is also subject to bombardment by extreme levels of radiation. As a result, scientists say the moon is likely to be covered in oxidants at its surface. These are created when water is ripped apart by energetic radiation and could possibly be used by lifeforms as a type of fuel.
For years scientists have been considering plans for a spacecraft that could orbit Europa, but overstretched budgets stalled Nasa’s plans. Pappalardo has been worked with colleagues over the past year at the applied physics lab at Johns Hopkins University to come up with the Europa Clipper.
The plan is for a spacecraft to orbit Jupiter and make several flybys of Europa, in the same way that the successful Cassini probe did for Saturn’s moon Titan.
“That way we can get effectively global coverage of Europa, not quite as good as an orbiter but not bad for half the cost . We have a validated cost of $2 billion over the lifetime of the mission, excluding the launch,” Pappalardo says.
However, Nasa’s priority for exploration missions do not extend beyond Mars at the moment.
In December, the space agency announced plans for another rover to be sent to Mars, in light of the ongoing success of the Curiosity rover which last week drilled its first hole into the planet’s surface to begin an examination of the soil.
According to The Guardian, under Nasa’s current mission timetable, there will be no probes in the outer solar system after Juno arrives at Jupiter in 2016 and crashes into the planet a year later. Nasa scientists may have a small role in the European Space Agency’s Jupiter Icy Moon Explorer (Juice) mission, but that will not reach those moons until around 2030.
Undaunted, Pappalardo says:
“Mars exploration is part of the bigger picture of human exploration. 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?”
He went on to say that whereas Mars might have been habitable planet billions of years ago, Europa might be an ideal habitable environment for life today.
To Pappalardo, the time is now for such a mission. If it takes 50 years before humans send probes and then terraformers to Europa,”we’re going to look back and say we should have been doing this all along, and that would be tragic,” he said.