The plan, nicknamed "tunnelbot", would offer an opportunity to delve deep beneath the distant world of Jupiter's moon Europa and check whether there are aliens hiding beneath its surface, as some researchers suspect.

The water hidden beneath Europa is considered one of the most promising places to find alien life in our own solar system. But it is stuck beneath a crust of ice, making it difficult to explore directly.

Now scientists have suggested that they could send the drill to dig into that crust and explore to try and find extraterrestrial life.

"We have performed a concept study for a nuclear powered tunneling probe (a tunnelbot) that can traverse through the ice shell and reach the ocean, carrying a payload that can search for nested, corroborative evidence for extant/extinct life," the researchers wrote in a proposal given at the 2018 meeting of the American Geophysical Union. "The tunnelbot would also assess the habitability of the ice shell and underlying ocean."

There are still a series of problems with the plan, including the question of how the tunnelbot would actually get all the way to the distant world. "How initial deployment on the surface would occur was not addressed and remains a challenge for future work," they note.

The researchers actually considered two possibilities: one that is powered by a nuclear reactor, and another by heat source bricks. Both use the heat generated from those power sources to melt through the ice sources.

But burying deep into the world would come with other challenges, too. It would be hard for messages to be able to be sent through the ice, for instance, meaning that the robot would carry a cable that could send messages back up and onto Earth.

The researchers also note that the tunnelbot would have to leave a cable or float when it reaches the ocean to make sure that it doesn't fall into the water when it digs through the ice.