Bigger brains, better batteries will enable new missions for robotic submarines.

• Author: Parsons, Dan

* Compared to the notoriety and money spent on unmanned aircraft, robotic submarines have garnered little attention or funding during their several decades of development.

As the Navy takes on a larger role in national security strategy following the conclusion of two land wars, unmanned underwater vehicles may have another shot at becoming a technology favored in future budgets.

"There's not a lot of money in underwater robots compared to unmanned aerial vehicles," Chris Mailey, vice president of knowledge resources at the Association for Unmanned Vehicle Systems International, told National Defense. "Globally, spending on maritime robots is about 8 percent of what is spent on unmanned aerial systems."

The Defense Department budgeted a little more than $1 billion for all unmanned maritime systems in fiscal year 2014, about half of which is aimed at procurement and development of underwater vehicles. The Pentagon plans to spend more than $5 billion on pilotless aircraft next fiscal year, according to AUVSI figures.

The six UUV programs of record--those that are being purchased and fielded--will be allocated a total of $88 million in fiscal 2014.

A major factor in the disparity between flying and underwater drones is that the U.S. military--a pioneer of unmanned technologies--has been fighting in landlocked nations over the past 12 years. UAVs and bomb-disposing ground robots gained all the glory in those conflicts, Mailey said.

So-called "gliding" submarines that use buoyancy instead of engines for propulsion cost about $100,000 apiece--a bargain compared to their multi-million-dollar flying counterparts that cannot see beneath the waves. A heavy reliance on commercially available technologies has driven the cost of UUV development and procurement down as well, he said. Most small and medium-sized robotic subs cost less than $1 million.

UUVs were capable of gathering intelligence and performing mapping functions in the early 1990s, but have faced budgetary and fiscal hurdles in the following years. Development of underwater robots has been aimed almost solely at explosives disposal. Any funding to build robots for other maritime missions has had to compete with larger legacy procurement programs, Mailey said.

"There hasn't been much evolution in the technologies since then," he said. "There has only been so much money to go around. Anything outside mine countermeasures is competing with other programs like the Ohio-class replacement submarines.

"If...