What Lies Beneath: Inside DARPA's Subterranean Challenge.

• Author: Harper, Jon

The military, law enforcement and search-and-rescue teams have different missions but face a common problem: operating underground. The Defense Advanced Research Projects Agency, better known as DARPA, is about to kick off a competition aimed at furthering robotics technology to help them do their jobs.

The subterranean operating environment is multifaceted. For example, militant groups like the Islamic State and Hamas have built extensive networks of underground passageways to move fighters and protect themselves from aerial attack. Drug cartels are using tunnels to smuggle contraband into the United States from Mexico. A former Thai navy SEAL died last year while trying to deliver oxygen tanks to kids trapped inside a cave.

Meanwhile, top defense officials believe the U.S. military will have to do battle in megacities and other urban areas that have complex underground facilities such as subway systems.

"Subterrain is just going to be something that we have to contend" with, said Army Lt. Gen. Robert Ashley Jr., director of the Defense Intelligence Agency. "That will be part of the war-fighting in the future."

The U.S. military will need technology to sense and understand what is taking place underground, he noted during remarks at a technology summit in Washington, D.C., last year.

"You may not want to put a person in there. You may not want to put a soldier at risk or a Marine," he said. "It may be something you do from a robotics standpoint where you put an autonomous vehicle into" the threat area.

DARPA's Subterranean Challenge is trying to address those needs. It's a multi-phase competition aimed at promoting robotics technologies that can traverse, navigate, map and search underground environments. It will feature three different circuits--tunnel, urban underground and cave--before culminating in the grand finale that combines elements of each.

"The genesis of the SubT Challenge is the ability for us to operate in... the underground environments where we can't take advantage of GPS, we cannot guarantee that there's even lighting, and certainly can't say that the terrain is going to be friendly," Tim Chung, the SubT program manager in DARPA's Tactical Technology Office, said during an interview at the agency's headquarters in Arlington, Virginia.

For the competition, DARPA is interested in four technical areas: mobility, perception, autonomy and networking. "They all have to come together in orde to get these things to work," said Chung

There are a number of different...