SUBTERRANEAN SHOWDOWN: DARPA Pushes Underground Robots to Their Limit.

• Author: Roaten, Meredith

LOUISVILLE, Ky. -- It was 6 a.m. and Lt. Col. Dan Riley was laying in his hotel room, staring at the ceiling.

Though he is an active duty Air Force officer, Riley was not "chair flying" an airplane, a pilot's way of practicing procedures before a flight. Instead, his mind was far below ground--running through every possible obstacle facing the menagerie of robots under his control in a network of caves, tunnels and urban underground environments.

As an operator in the final competition of the Defense Advanced Research Projects Agency's Subterranean Challenge, he was the only one on his assembled 16-person robotics team Marble who was allowed to issue commands during the perilous hour of competition.

Only the day before, professional sportscasters hired by DARPA analyzed and speculated about failed unmanned aerial system take-offs, friendly robot collisions and fog-obscured sensors in the challenge's preliminary runs. He also was the lead for the competition that took place in the virtual realm, helping write the code for the autonomous systems to explore a cave and tunnel simulation. But Riley's long history in the Air Force equipped him for racing against the clock and operating delicate systems under pressure, he said.

"There's definitely a lot of stress involved," he said. "You feel the weight of everyone's expectations riding on what you're going to do."

This challenge was the final round of DARPA's SubT project aimed at accelerating the development of autonomy and robotics for search-and-rescue operations. Firefighters and first responders could soon command fleets of robots capable of pinpointing unseen hazards and locating survivors, Program Manager Tim Chung said in late September under the glow of the stage lights that filled the event's watch party at the Louisville Mega Caverns in Kentucky.

With $3.5 million on the line for the final challenge, it was not the time to play it safe.

On the surface, the eight teams competing in the systems challenge had a simple objective: locate as many objects as possible in one hour. But as the three winners who left the caverns with huge, lottery-style checks for $2 million, $1 million and $500,000 would find out, the labyrinth that took weeks to construct would test the limits of mapping, autonomy, robotics and communications capabilities that some of them had been developing for years.

The course was designed to highlight what is possible for the warfighters and first responders who could one day use the mapping, austere navigation, robotics and autonomous hardware and software to conduct subterranean operations, Chung said.

Prize-winning teams Cerberus and CSIRO Data61 scored 23 points, and the lowest scoring teams--Robotika and Coordinated Robotics--each detected two objects.

After an earthquake or a collapsed building, "There's always a gear turning in the back of my head--and for many of our competitors I'm sure--that in the event of some kind of emergency, what one of our robots could go out and help?" he said. "You've been able to push the entire frontier of this technology, but there are many people out there in this audience are grateful for even just the one piece of technology that you've advanced. That's so meaningful to me."

During the competition, each team had one...