So far, the only robots to be sent to the Martian surface have come in the form of stationary landers or mobile rovers. But could the next generation of robotic Mars explorer come in the form of a… snake?

This little bit of lateral, slithery thinking comes from researchers at SINTEF (Stiftelsen for Industriell og Teknisk Forskning), a research institute based in Trondheim, Norway, who have built prototype robotic snakes that could explore where no Mars rover has ever explored before.

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The key problem with any robotic Mars exploration effort is that of maneuverability, even the most agile of wheeled rover has limits on what it can do. The best thing about snakes is that they are the ultimate contortionists able to probe any nook and cranny, avoiding hazards along the way.

“Manoeuvrability is a challenge. The Spirit rover was lost after it became stuck in the sand on Mars. The vehicles just cannot get to many of the places from which samples have to be taken”, said SINTEF researchers Pål Liljebäck and Aksel Transeth.

This work is based on a feasibility study funded by the European Space Agency (ESA), which is investigating different ways of exploring and sampling planetary surfaces. The SINTEF study focuses on a snake-like appendage for a more traditional Mars rover.

Like NASA’s Mars Science Laboratory’s robotic arm that is used to get up-close and personal with rocky samples, focusing the attached MAHLI (Mars Hand Lens Imager) camera on small-scale geological features, a snake-like probe could go one better, detaching itself and “slithering” up to samples and collecting them from hard-to-reach locations.

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“We are looking at several alternatives to enable a rover and a robot to work together,” said Transeth. “Since the rover has a powerful energy source, it can provide the snake robot with power through a cable extending between the rover and the robot. If the robot had to use its own batteries, it would run out of power and we would lose it.”

“One option is to make the robot into one of the vehicle’s arms, with the ability to disconnect and reconnect itself, so that it can be lowered to the ground, where it can crawl about independently.”

The independent nature of the robotic snake means that it could also come to the aid of its rover “mother ship” should its wheels get stuck in loose regolith. The snake could coil itself around a rock, and via an attached winch, the rover could use the snake as an anchor, pulling itself loose.

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Norwegian researchers have worked on snake robot technology for several years and the robotics are beginning to mature.

Artist's concept of a small snake robot exploring Mars along with a rover.
Credit: Copyright James Steidl/Shutterstock.com

Watch a video of a SINTEF snake prototype in action:

Image: SINTEF researchers Pål Liljebäck and Aksel Transeth, and Knut Robert Fossum of NTNU’s CIRiS, are playing with Wheeko the snake robot. Credit: SINTEF/Thor Nielsen

Mechanical "snake robots" could boost the scientific output of next-generation Mars rovers and get them out of jams from time to time, researchers say.

Small, serpentine robots could help Mars rovers collect soil samples from crevices beneath rocks and other hard-to-reach places, and they could pull their wheeled siblings to safety if the bigger vehicles get bogged down in soft sand.

"The connection between the robot and the rover also means that the snake robot will be able to assist the vehicle if the latter gets stuck," said Pål Liljebäck, a researcher with the Foundation for Scientific and Industrial Research in Norway, or SINTEF.

"In such a situation, the robot could lower itself to the ground and coil itself around a rock, enabling the rover to pull itself loose by means of the cable winch, which the rover would normally use to pull the snake robot towards the rover," Liljebäck said in a statement.

Such a backup may have been able to save NASA's Spirit rover, which got stuck in 2009 after exploring the Red Planet for five years. Unable to point its solar panels toward the sun over the Martian winter, Spirit stopped communicating with Earth in 2010 and was declared dead a year later.

SINTEF, with assistance from the Norwegian University of Science and Technology, is currently conducting a 500,000 Norwegian krone (US $84,700) feasibility study for the "snake robot" technology.

SINTEF researchers envision a Mars rover carrying the snake much of the time, dropping the smaller robot at soil-collection sites or other areas of scientific interest. The rover could then analyze the snake-snagged soil or set it aside for transportation back to Earth. 

The snake could fit atop or underneath the rover, as long as the wheeled vehicle were outfitted with some sort of hoisting mechanism to pick it up. But there are other possibilities as well.

"One option is to make the robot into one of the vehicle's arms, with the ability to disconnect and reconnect itself, so that it can be lowered to the ground, where it can crawl about independently," said Aksel Transeth, also of SINTEF.

The European Space Agency expects to receive a more specific proposal in December from the researchers. There's no word yet, however, on when the snake could crawl on Mars. ESA is planning a Red Planet rover to launch in 2018 as part of the ExoMars mission.