Europe may be the most likely place to host foreign life. Underneath its surface is a salty sea, warmed by the burial game of the moon's metal core. But how are you through archives?
You melt down with a nuclear-powered robot.
At least, it is the proposal of the United States Geophysical Union Meeting in Washington DC this week.
Nasas Glenn Research Center's interdisciplinary COMPASS team was founded to develop technology to overcome the challenges of space exploration.
Europe is a big one.
The ice that covers this extent of Jupiter can be somewhere between 2 and 30km thick.
But below it can be life.
To find it will open our understanding of how common life is in our universe, how robust it is – and how it occurs.
Planetaric researchers are not even some Europe having a sea. But all signs indicate that it has. The most enticing of these is the plumman of liquid water that periodically breaks out of its surface.
The COMPASS team has conducted a concept study on technology that can penetrate the ice with a series of sensors and send data that collects to the ground.
The best option, as they argue, is a nuclear-powered submarine.
Nuclear power packs most energy in a small space.
And it does not even need to be built into a nuclear reactor – but it was one of the concept designs. In its simplest form, radioactive "bricks" would simply radiate a heat source in front of a tubular probe which then gradually decreases when the ice below turns to wreck.
The power of such nuclear fuel cells has been clearly demonstrated by those like Voyager 1 and 2, which still send back signals when they pass into interstellar space about 40 years after they were launched.
The nuclear "tunnel" would distribute from a landlord with a fiber optic string of data repeaters unfurling when it's sinking.
Such a subway of Europe would be relatively large. And risky to start.
"We did not worry how our submarine would make it to Europe or be deployed in the ice," said University of Illinois at Chicago teacher Andrew Dombard. "We just assumed it could get there and we focused on how it would work during descent to the ocean."
What is the purpose of their mission. Whether or not such a nuclear-powered submarine is being built and distributed is the next step. But the decision will be based on an informed study of what it would take to peek under ice ice.
Sending a probe to Europe is one of Nasa's great ambitions in the coming decades. But getting the mission past an increasingly skeptical US Congress may not be easy.
On thin ice
The project's main advocate was Texas Republican John Culberson, who organized the subcommittee as Nasa funds. The Nasa study that produced the nuclear-powered tunnel was the result of his efforts.
But he lost his seat in the last half-time election.
And President Donald Trump's latest budget line says he does not intend to fund a European landlord.
Some experts express the fear that such an attempt would be a "bridge too far": we simply do not know enough about the odd moon, anyway.
"It's a mission that came out of Congress as opposed to an assignment that came out of science," says planetary society's Emily Lakdawalla.
Others argue for the long lead for such ambitious missions, it is now time to start working for the project.
And we will learn more about the mysterious moon anyway.
The Europa Clipper mission – a space probe designed to run the moon – has received initial funding. The goal is to circulate as little as 25 km for up to three years, map Europe's ice-cream surface and brag about what chemicals can spread in their plumes.
It is hoped that Clipper will be ready for launch in 2022. It takes six years for the probe to reach Jupiter and establish itself in orbit around Europe.