Subterranean Environment Challenge is Becoming More and More Relevant

Subterranean Environment Challenge is Becoming More and More Relevant

A lateral tunnel running off the main Malinta Tunnel on Corregidor Island lies in ruins 75 years after attacks and intentional detonations by the Japanese as seen May 10, 2017. The main tunnel served as a Headquarters for the Army and housed hundreds of people during the war and subsequent siege by Japanese Forces. Lt. James Crotty tried to defend the position until American and Filipino Forces were overwhelmed. (U.S. Coast Guard photo by Chief Petty Officer Sara Muir/Released)

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Underground environments pose significant challenges for situational awareness of first responders and military forces in several levels. Tunnels can extend many kilometers in length and include highly constrained passages, multiple levels, and vertical shafts. Urban underground environments are often more structured and constructed out of human-made materials, but can have complex layouts that cover multiple stories and/or span multiple city blocks. Natural cave networks often have irregular geological structures, with both constrained passages and large caverns, and unpredictable topologies often stretching large distances in extent and depth.

The US Department of Defense wants to enhance its capabilities in this field. The Defense Advanced Research Projects Agency has organized a Subterranean Challenge (SubT) in order to help military and civilian first responders overcome issues associated with operating underground, including constrained passageways and limited situational awareness. DARPA is interested in human-built tunnel environments such as mines, as well as underground urban settings

The SubT Challenge explores new approaches to rapidly map, navigate, search, and exploit complex underground environments. The challenges refer to both physical platforms as well as software and algorithms through virtual events.16 teams competed in the virtual cave circuit in November. During the event, competitors used their technology to traverse through eight simulated caves, which were designed by Angela Maio, virtual competition lead for DARPA’s SubT Challenge, using information from real man-made caves, she said during the competition. The competing teams submitted their software before it kicked off with the expectation that their systems could autonomously map, navigate the caves, find artifacts and coordinate with multi-robot teams all while operating in degraded communications environments in the virtual realm.

During the virtual exercises, the agency is able to test teams who coordinate their robots to autonomously perform, including communicating with each other and finding out how to explore the environment.

Coupled with the cave scenario, which are for naturally occurring cave networks, all [of this is] culminating in technology development that will allow for us to be able to address all three of these subdomains and do so in a way that isn’t always tuning or tweaking, but rather more holistically addressing the diverse challenges in these environments.

DARPA held its subterranean tunnel circuit in August 2019. An urban circuit took place in early 2020. The final event, which will be a culmination of all three terrains, will take place in late 2021, according to, based on DARPA.