The Navy completed a first-of-its-kind test last month when an unmanned surface vessel was refueled without the help of any onboard personnel in a demonstration that marks a step forward for the Defense Advanced Research Projects Agency's No Manning Required Ship (NOMARS) program.
Conducted by DARPA in coordination with the Navy’s unmanned maritime systems program office (PMS-406) and USV Squadron 1 (USVRON-1) using the USVs Ranger and Mariner, the test demonstrated refueling technology designed by contractor Serco for use aboard the future NOMARS USV Defiant.
The NOMARS initiative was launched in 2020 with the goal of developing an unmanned platform capable of operating for up to a year without human intervention or maintenance. Serco was selected to build the first vessel in 2022, and in April, Navy officials said NOMARS would transition to the service in 2025.
During the demonstration, Ranger carried a “receiving station” designed for the future Defiant while Mariner deployed a refueling probe to complete the operation, according to a Dec. 19 DARPA announcement. Personnel were present on both vessels during the test but were not involved in operations on the fuel-receiving side.
“The team demonstrated all parts of the system [concept of operations] while underway, including passing the lead-line to the refueling side, passing and connecting the refueling probe to the USV side and pumping water. This was the first on-water test of the system, and all parts of the operation were successfully demonstrated,” the announcement states.
Current USV refueling techniques require people to board the vessel to handle lines and hoses, the notice continues. The presence of people on the USV imposes restrictions on its design and operations, while the refueling process itself can be dangerous for personnel in rough seas.
The next at-sea refueling test is slated to take place using the Defiant USV during the vessel’s sea trials. The 180-foot-long, 240-metric-ton vessel is nearing the completion of construction and is scheduled to begin a “multimonth at-sea demonstration” in the spring of 2025, the notice states.