The U.S. Navy secretly tested advanced hyper velocity projectiles capable of executing multiple missions for a number of gun systems during the Pacific (RIMPAC) 2018 international exercise.

Twenty hyper velocity projectiles or next-generation, common, low drag, guided projectile were fired from the destroyer USS Dewey (DDG-105) as part of a study conducted by the U.S. Navy and the Defense Department’s Strategic Capabilities Office (SCO), unnamed officials familiar with the test told USNI on Monday.

USNI News got the scoop on the previously unannounced tests, citing anonymous sources, but did not say specifically when the test firing had occurred or if the experiments had successfully fulfilled all of the test points.

According to USNI media report, the test, conducted by the Navy and the Pentagon’s Strategic Capabilities Office as part of the Rim of the Pacific (RIMPAC) 2018 international exercise, was part of a series of studies to prove the Navy could turn the more than 40-year-old deck gun design into an effective and low-cost weapon against cruise missiles and larger unmanned aerial vehicles.

The hyper velocity projectile is being cast as a low-cost alternative to the weapons currently used against cruise missile threats. Each Evolved Sea Sparrow Missile, for example, costs $2 million; every Rolling Airframe Missile runs another $1 million; shooting a single Standard Missile 2 has a price greater than $400,000.

“If you think about the kinds of threats you might face in the Middle East, the lower-end cruise missiles or a larger UAV, now you have a way to shoot them down that doesn’t require you use a $2 million ESSM or $1 million RAM, because a hyper velocity projectile — even in the highest-end estimates have it in the $75,000 to $100,000 range, and that’s for the fanciest version of it with an onboard seeker,” Bryan Clark of the Center for Strategic and Budgetary Assessments told USNI News.

Officials told the publication the RIMPAC test was unclassified, but the Office of Secretary of Defense and the Office of Naval Research have declined to acknowledge it.

The hyper velocity projectile (HVP) is a next-generation, common, low drag, guided projectile capable of executing multiple missions for a number of gun systems, such as the Navy 5-Inch; Navy, Marine Corps, and Army 155-mm systems; and future electromagnetic (EM) railguns. Types of missions performed will depend on the gun system and platform, but range from Naval Surface Fire, to Cruise and Ballistic Missile Defense, Anti-Surface Warfare and other future Naval mission areas.

The HVP’s low drag aerodynamic design enables high-velocity, maneuverability, and decreased time-to-target. These attributes, coupled with accurate guidance electronics, provide low-cost mission effectiveness against current threats and the ability to adapt to air and surface threats of the future.

The high-velocity compact design relieves the need for a rocket motor to extend gun range. Firing smaller, more accurate rounds decreases the likelihood for collateral damage and provides for deeper magazines and improved shipboard safety.