For a human trapped under rubble, any shape a rescuer can take is welcome, even if that rescuer is an articulated robot snake. The ZMEELOK-3M, developed in Russia by RTK, is a modular platform designed for use in urban rescue. It could also see military applications, a mechanical sensor platform slithering into caves to scout ahead of much more vulnerable humans.

“This is a prototype, but we are seeing that the Russian military is not only thinking creatively about technologies that can assist its war fighters — it also is following in the footsteps of other advanced militaries like the Israeli army that has built a similar snake robot earlier,” said Samuel Bendett, an adviser at the Center for Naval Analyses.

Part of that creativity comes through in the modular design. The robot is built with internally identical sections, weighing 12 ounces and roughly 3 inches in length and diameter each. The foremost segment, which functions as a head, carries a light and cameras and additional sensors. According to RTK, the design can be as small as four segments long and as long as 15 segments together. The developers also claim that the whole of the robot snake can be controlled through any module, so long as one remains connected to its remote operator.

“Such a robot can prove very valuable in urban and subterranean combat — it can crawl where other small tracked or wheeled UGVs cannot. No doubt, Russian military will want to test such a robot given that in Syria, the [Ministry of Defense] has encountered subterranean tunnels used by anti-Assad forces,” said Bendett, a fellow in Russia studies at the American Foreign Policy Council.

“Russians also note that in their own experience in Afghanistan, and in the American experience fighting in that country, such tunnels have been widespread by anti-government fighters. Today, Russian military is starting to utilize small UGVs for ISR in Syria — such as “Scarab” — but it has so far never had its own snake robot.”

Indeed, in its report on the ZMEELOK-3M, the Russian newspaper Izvestia quotes Valery Yuriev, representative of Russian veterans of the Afghanistan war, as saying that the snake robot would have proved valuable for scouting out caves, since sending human soldiers into combat underground was likely to lead to a tragic end.

Caves have proved one of the hardest domains to crack. It remains a frontier for military robots, with DARPA in the United States sponsoring a series of challenges to better explore the possibility of autonomous machines in both rescue and combat operations.

The rocky walls and natural interference of underground make remote control difficult. RTK states that the ZMEELOK-3M has a radio control range of about 330 feet, and a top speed of about 1.6 feet/second. That makes it a useful extension of an infantry unit, but not a far-ranging scout that can go forth, discover people, and return with useful information.

Looking to the drone’s animalian analog, RTK is interested in developing both terrestrial versions and a swimming, submersible mobile, already dubbed the ZMEELOK-AQUA.

What is perhaps most intriguing about the snake robot are the kinds of sensors envisioned for it. Right now, dogs possess one of the most powerful search-and-rescue sensors in the form of their nose. RTK envisions a version of the ZMEELOK in the future that pairs the standard video and infrared sensors with a new sensor that can “smell” underground.

Because if there is anything people trapped underground want to see as a sign of rescue, it’s not just a robotic snake. It’s a robotic snake that found its way by sense of smell.