Some of the most tantalizing targets in space exploration are frozen ice worlds. Take Jupiter's moon Europa, for instance. Its warm, salty subsurface ocean is buried under a moon-wide sheet of ice. What's the best way to explore it?

Maybe an ice robot could play a role.

Though the world's space agencies—especially NASA—are getting better and better at building robots to explore places like Mars, those robots have limitations. Perhaps chief among those limitations is the possibility of breakdown. Once a rover on Mars—or somewhere even more distant—breaks down, it's game over. There's no feasible way to repair something like MSL Curiosity if it breaks down while exploring the Martian surface.

But what if the world being explored was a frozen one, and the robot was made of ice? Could icy robots perform self-repair, even in a limited fashion? Could they actually be manufactured and assembled there, even partly?

Prepping for a spacewalk typically means diving underwater to rehearse and fine-tune operations.

In 2016, ESA astronaut Alexander Gerst performed such an underwater rehearsal for the ColKa high speed radio, the brown box imaged above, that will be installed this month on the International Space Station.

NASA astronauts Mike Hopkins and Victor Glover will integrate the small fridge-sized device outside the European Columbus module during a spacewalk scheduled this year. ESA astronaut Andreas Mogensen will be at NASA's mission control directing the spacewalkers as Capcom. The Columbus Ka-band terminal, nicknamed "ColKa," will enable faster communication with Europe.

Orbiting the planet every 90 minutes means the Space Station is constantly making and breaking short links with ground stations on Earth as it passes over them at a height of 400 km.

With Colka, a European telecommunications satellite in geostationary orbit can pick up data sent from the Columbus module. This satellite is part of the European Data Relay System and will be able to directly relay the signals from Columbus to European soil via a ground station in Harwell, in the U.K.