WASHINGTON – A U.S. Missile Defense Agency review of a failed ballistic missile intercept test showed that a mistaken input into the combat system by a sailor on the destroyer John Paul Jones caused the missile to self-destruct before reaching the target.

A tactical datalink controller, in charge of maintaining encrypted data exchanges between ships and aircraft, accidentally identified the incoming ballistic missile target as a friendly in the system, causing the SM-3 missile to self-destruct in flight, according to a source familiar with the test.

The head of MDA did not comment on the sailor error, but said in a statement that the ongoing review confirmed it wasn’t an issue with the SM-3 Block IIA missile or the Navy’s Aegis combat system.

“Though the review is still in process, the SM-3 IIA interceptor and Aegis Combat System have been eliminated as the potential root cause,” of the failure, said Air Force Lt. Gen. Sam Greaves, the director of MDA.

“We are conducting an extensive review as part of our standard engineering and test processes, and it would be inappropriate to comment further until we complete the investigation.‎”

The test marked the fourth flight test of the SM-3 Block IIA and the second time it was launched from a ship. The missile successfully intercepted a ballistic missile target in a February test launch. The missile is being developed by Raytheon and is a joint project between the U.S. and Japan, designed to counter rising missile threats from North Korea and others.

The revelation that human error likely caused the failed test on June 22 is a relief to the military and contractors racing to advance BMD technology as the threat from ballistic missiles is on the rise.

The silver lining is that there appears to be that there are no issues with the interceptor, said Thomas Karako, a missile defense expert with the Center for Security and International Studies.

“As unfortunate as this might be, it’s a good thing that this wasn’t a technology issue or some deeper failure that needs to be investigated at great length and time,” Karako said. “There is no reason to believe the basic capability that has already been demonstrated has any new problems.”

John Paul Jones is the Navy’s missile defense ship; it replaced the cruiser Lake Erie in 2014. Lake Erie was the test ship since 2000 and is currently on deployment in the Asia-Pacific region.