The deployment of the powerful Sea-Based X-Band Radar from Pearl Harbor in March was hailed as a significant precaution in the face of a possible North Korean missile launch.
For whatever it means, the SBX now is back.
Navy Region Hawaii said the towering radar returned to Joint Base Pearl Harbor-Hickam just before 8 a.m. Friday.
The command referred questions to the Pentagon and Missile Defense Agency, neither of which could be reached Friday afternoon Hawaii time.
U.S. military officials said in mid-April that the phased-array radar was in place in the Pacific to track missiles fired by Pyongyang.
CNN reported Tuesday that North Korea had withdrawn two mobile ballistic missiles in a possible hint of easing tensions.
The unpredictable regime has fired test missiles before when signs pointed to a de-escalation, however.
"What we have seen recently is a provocation pause," CBS News quoted Pentagon spokesman George Little as saying.
Navy Region Hawaii said the 280-foot-tall radar tracking system got underway March 22 "to conduct routine systems checks at sea."
In early April, Little said the radar was conducting semiannual systems checks and that no decision had been made about further deployment, ABC News reported.
A U.S. official shortly after confirmed that the SBX had been sent out into the Pacific on an operational missile-defense mission, the news agency said.
The U.S. sent two destroyers to the western Pacific with ballistic missile shoot-down capability and decided to deploy a ground-based Terminal High Altitude Area Defense system to Guam.
The deployment of the SBX, a fixture at a Ford Island pier for much of the past year, was the second in recent years amid heightened concerns over North Korea's missile program.
The one-of-a-kind, $1 billion radar, which has the appearance of a giant golf ball on a six-legged platform, sailed out of Pearl Harbor a year earlier on March 23, 2012, about three weeks ahead of what ended up being a failed North Korea rocket test the following month.
The phased array inside the SBX's inflatable dome tracks U.S. and foreign missiles with 45,000 transmission and receiving elements, and is so powerful it could see a baseball flying through the air 2,500 miles away, according to the Missile Defense Agency.
The Missile Defense Agency said in February 2012 that it planned to sideline the missile tracker by placing it "in a limited test and contingency operations status" to save $500 million over five years.
Boeing had a maintenance and operation contract for the SBX prior to the Missile Defense Agency's transfer of the vessel to the Military Sealift Command, officials said.
The Navy awarded a $101.2 million contract to Gryphon Technologies in January 2012 for the work.