With the help of a National Geographic Innovation Fellow, a team of engineering students from Colorado State University and additive manufacturing technologies from Solid Concepts build an Underwater Remotely Operated Vehicle unlike any before that will soon dive into the forgotten places of the earth.
Cave diving is a high-risk sport. It’s an exclusive sport, saved only for the master divers of the world, and even then it’s a risk few are willing or able to take. For this reason, Corey Jaskolski, president of Hydro Technologies and a National Geographic Innovation Fellow, embarked upon a mission to develop remotely operated vehicles to explore underwater caves instead of their human counterparts. His ambitious mission involved creating a small, portable and easily assembled underwater remotely operated vehicle, or UROV. The design required manufacturing and engineering expertise to become a vehicle that might go where no man, or robot, has gone before.
Jaskolski is primarily known for his work on the first pressure tolerant Lithium Polymer battery, which facilitated robotics operations for the filming of James Cameron’s Titanic documentary, “Ghosts of the Abyss,” in 2001. Jaskolski served as director of technology at the National Geographic Society developing marine imaging systems. He then founded Hydro Technologies to further commercialize technologies for ocean surface and underwater applications.
“There are very few places where you can make new discoveries or find new species,” said Jaskolski. “However, underwater is a unique environment.”
Before scuba diving became an accessible sport, deep-water cave exploration remained in the periphery, leaving hundreds of thousands of artifacts buried underwater from millennia of geographical changes on the earth’s surface.
Water continuously changes its distribution across the continents; sacrificial vistas where victims were killed to appease deities are now underwater with carefully preserved burial chambers waiting to be discovered.
“These places haven’t even been looted by people yet,” said Jaskolski. “But now, with the increase in scuba diving and commercialization of deep water gear, recreational divers can traverse underwater caves, laying out air tank after air tank behind them. And people are dying every year. Life insurance now asks if you sky dive or cave dive. I never had to fill that out before.”
Jasloski’s UROV should remove some of the danger of these dives.
Current ROVs, built largely for the oil and gas industry, are often purposed for seeking planted mines on the hulls of ships or aircraft. These ROVs are gargantuan systems laden with tether and wire, impractical for explorers based on weight, let alone affordability.
“There are great archeological teams unable to afford current UROVs; they can barely afford to travel out to these places for exploration,” said Jaskolski. “If we can make UROVs readily available, cheap, portable and easily replicable and get them in the hands of the right people, then we will be able to make amazing discoveries in our lifetime.”
Jaskolski turned to Colorado State University (CSU) and additive manufacturing company Solid Concepts to create a compact, 3D-printed UROV. “If everything had to be made by machining or molding without freedom to design one-off or two-offs, this would not have been possible,” said Jaskolski. “It would have turned into months of machining and hundreds of thousands of dollars.”
Instead, the resultant UROV took a few weeks to 3D print and ship out for testing. It is fondly known as NEMO.
NEMO, an acronym for Nautical Exploratory Modular Observer, is a combination of today’s leading technology and manufacturing processes. The vehicle’s bright orange body was manufactured using 3D printing Fused Deposition Modeling (FDM), a process that extrudes heated ABS thermoplastic through a fine nozzle layer by layer. Control surfaces were manufactured with Selective Laser Sintering (SLS), another additive manufacturing process. SLS uses CO2 lasers to sinter a bed of powdered nylon layer by layer.
The clear nose cones on either end of NEMO were manufactured first with a Stereolithography (SLA) master pattern. The SLA master pattern was then used to form a silicone mold, which was cast with urethanes through the QuantumCast Cast Urethane process. The process allowed each thread to be cast directly into the nose cones, eliminating further machining. The process also used a soft tool, which significantly cut down on manufacturing costs.
“Because of additive manufacturing abilities, this vehicle looks better than any other vehicle I’ve seen,” said Jaskolski.
Michael Hake was the lead engineer for the team that designed and constructed NEMO at CSU. “Corey [Jaskolski] saw the need to revolutionize current UROVs because a lot of explorers have been dying in underwater caves,” said Hake, who now works with Jaskolski at Hydro Technologies. “NEMO can do everything a scuba diver can do and more.”
UROVs traditionally use a generator tethered to the surface to maintain extended operation. Thick, heavy wires snake from the surface to the vehicle to control operations. An extreme amount of power is pumped into UROVs to keep the current low and to avoid power loss. Hake and his team engineered a method to power the vehicle from on board rather than through a generator.
“Old UROVs powered from the surface required 120-m-long cables half an inch in diameter and composed of solid steel—a tremendous amount of weight,” said Hake. Instead, NEMO is completely powered on board, though it is still tethered to the surface to maintain communication with a thin fiber-optic cable weighing less than 4 lb.
The orange FDM 3D-printed shield provides protection for the main pressure vehicle; it’s a vital shield, as a small nick could potentially damage the internal mechanisms once NEMO reaches low temperatures. The shell additionally provides a mount for all thrusters facilitating vehicular propulsion.
“It’s a nice, easy-to-assemble package,” said Hake. “The servos and thrusters all connect directly to NEMO’s outer shell, significantly decreasing part and manual assembly count. Instead, you can easily remove the shell without losing parts and reassemble when you reach your destination.”
NEMO’s thrusters and servos combine to make the UROV exact, similar to driving a radio or remote controlled airplane on a smaller, watery, scale. Additionally, the servos give NEMO more power than a typical model plane.
NEMO will withstand a depth of more than 60 m, the depth at which most master scuba divers will turn back; an average scuba diver is comfortable around 40-m deep. During analytic testing, Hake determined NEMO would withstand pressures at 190 m; however, at such a depth, the risk of electrical components experiencing damage increases exponentially.
NEMO will be capable of collecting samples from its environment, and is equipped with a camera to document its journeys. It’s compact enough for explorers traveling light and easy to assemble upon reaching the designated lake or underwater cave. Currently, Hydro Technologies aims to test NEMO in the high altitude lakes of Colorado, which haven’t been explored due to the increased risk of decompression sickness (“the bends”) in high up and cold regions.