A trick inspired by Hansel and Gretel could help rovers explore other worlds

In the classic fairy tale, Hansel and Gretel dropped bread crumbs while walking through a treacherous forest so they wouldn’t lose their way. Rovers may one day use a similar trick to traverse other planets without losing their data.

Typically, if a rover permanently loses communication during a mission, all the information that it has gathered is lost. To avoid this, researchers suggest using a multi-rover system in which a smaller rover piggybacks on a larger “mother rover.” The smaller rover would then venture into any especially uncertain territory, such as a cave or lava tubes, deploying sensors the size of an AirPods case like bread crumbs as it goes.

The sensors could then communicate with each other via a wireless network and funnel any collected data back to the mother rover, theoretical physicist Wolfgang Fink and colleagues propose February 11 in Advances in Space Research. As proof of concept, the team built prototype sensors that communicate via Wi-Fi.

It’s not that the smaller rover would be following the “bread crumbs” back the way it came. Instead, “we use [the sensors] for the data to find its way communication-wise out of the cave to the mother rover,” says Fink, of the University of Arizona in Tucson.

The technology could also be useful here on Earth, especially after a natural disaster such as an earthquake. A rover could be sent with the deployable sensors into rubble where it’s too dangerous for people to perform search-and-rescue missions (SN: 12/3/14).

The bread crumb–like communication network could allow researchers to “cater to the essence of scientific exploration,” Fink says, by allowing rovers to overcome some of the constraints posed by tricky terrain. “To get to the real exciting science, you most of the time have to go to exotic places, hard-to-get-to places.”