The Remote Minehunting System, or RMS, was developed for the Navy's new littoral combat ship. But the Defense Department's Office of Operational Test & Evaluation says the drone hunting technology was unable to consistently identify and destroy underwater explosives during tests dating back to September 2014.
"The Navy has determined that the RMS' total number of failures and periodicity of failures fall short of the design requirement for the system," said Capt. Thurraya Kent, a spokeswoman for the Navy.
Frank Kendall, the Pentagon's undersecretary of defense for acquisition, has scheduled a review of the program for early 2016.
The controversial unmanned mine-hunting drone, built by defense giant Lockheed Martin, is supposed to be a key component of the Navy's littoral combat ships.
In theory, the drone is deployed from the LCS towing sonar detection into suspected underwater minefields. The drone should then identify mines and communicate information about their whereabouts to the ship in real time so the explosives can be avoided or destroyed.
But the program has come under fire from lawmakers after a series of testing failures, including continued performance issues and "RMS mission package integration challenges," according to the Defense Department's Office of Operational Test & Evaluation's 2014 annual report.
The drone has continued to experience testing issues in 2015, according to an August 3 memo from Michael Gilmore, director of Operational Test and Evaluation, to Kendall.
"Recent developmental testing provides no statistical evidence that the system is demonstrating improved reliability, and instead indicates that reliability plateaued nearly a decade ago," Gilmore wrote.
Specifically, testing revealed that the vehicle "cannot be reliably controlled by the ship or communicate when it is operating out of the line-of-sight of the ship, and the towed sonar cannot detect mines consistently," according to the DOT&E.
The memo, cited in a September Senate Armed Service Committee report, also said the drone could only reliably operate for up to 25 hours before it failed during testing, falling far short of its required 75 hours.
Despite criticism from several lawmakers, the impending review by Kendall and an additional, ongoing independent review chartered by Navy officials, Lockheed Martin said it stands behind the underwater drone system.
"Lockheed Martin continues to work closely with the U.S. Navy on the Remote Minehunting System mission package, which remains the most advanced method of mine-hunting available to the U.S. fleet," said Joe Dougherty, a Lockheed Martin spokesman.
"We fully supported the Navy's independent review team when they visited our site in October, and demonstrated a clear path forward for RMS. We remain confident the RMS is the most mature system to identify and destroy mines in challenging conditions without putting sailors or high-value capital ships at risk in a minefield," he wrote.