Mars rovers could use a Hansel and Gretel-inspired trick to explore caves on the red planet: study

While cities on Earth are locked in a perpetual struggle to solve housing shortages, the market on Mars is already heating up.

Engineers at the University of Arizona have developed a system they say could allow autonomous vehicles to scout out habitats for astronauts in caves and other underground features. It’s been a long time since humans thought of caves as home, but the researchers say subterranean features on the red planet will offer some of the best options for shelter when humans finally make it to Mars.

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"Lava tubes and caves would make perfect habitats for astronauts because you don't have to build a structure," Wolfgang Fink, an associate professor of electrical and computer engineering at the University of Arizona, said in a media release. "You are shielded from harmful cosmic radiation, so all you need to do is make it pretty and cozy."

Fink and his co-authors detailed how the system works in a peer-reviewed study published in the scientific journal Advances in Space Research on Feb. 11. Their approach involves a communication network that would link different types of rover vehicles through a "mesh topology network."

These independent rovers would be deployed by a larger "mother" rover and travel over, and under, the Martian surface on their own, continuously monitoring their environment and maintaining awareness of where they are in space. They would also keep in touch with each other via a wireless data connection.

To avoid travelling outside of communication range and getting lost, the rovers would deploy communication nodes along the way, just like Hansel and Gretel leave a trail of breadcrumbs in the classic German fairy tale.

In a nod to the fabled siblings, the team has named their patent-pending system the "Breadcrumb-Style Dynamically Deployed Communication Network" paradigm, or DDCN.

"In our scenario, the 'breadcrumbs' are miniaturized sensors that piggyback on the rovers, which deploy the sensors as they traverse a cave or other subsurface environment," Fink said.

Once a rover senses the signal is fading but still within range, it drops a communication node, regardless of how much distance it has covered since it placed the last node.

"One of the new aspects is what we call opportunistic deployment – the idea that you deploy the 'breadcrumbs' when you have to and not according to a previously planned schedule," Fink said.

Fink and his co-authors say their novel approach could help address one of NASA's Space Technology Grand Challenges by providing the technology needed to safely traverse environments on comets, asteroids, moons and planetary bodies. NASA's Grand Challenges are an open call issued for innovative solutions that solve critical space-related problems, like the need for mobility systems that allow humans and robots to explore on, over or under any destination surface.

The DDCN concept can work in one of two ways. In one mode, a mother rover passively receives data transmitted by rovers as they explore Martian caves and lava tubes. In the other, the mother rover acts as the orchestrator, telling the rovers' where to go.

Both modes should allow a team of rovers to navigate underground environments without ever losing contact with their "mother rover" on the surface. Equipped with a light detection and ranging system, also known as lidar, the rovers could even map out cave passages in three dimensions.

The paper has attracted some attention in the field of solar system exploration, drawing praise from Dirk Schulze-Makuch, president of the German Astrobiological Society.

"The communication network approach introduced in this new paper has the potential to herald a new age of planetary and astrobiological discoveries," Schulze-Makuch said in a media release.

"It finally allows us to explore Martian lava tube caves and the subsurface oceans of the icy moons – places where extraterrestrial life might be present."