It’s back. Again.

The 280-foot-tall, $900 million Sea-Based X-Band Radar, otherwise known as the giant floating golf ball, has returned to Pearl Harbor.

It is the latest in a series of frequent stops here by the distinctive "SBX," which is part of the U.S. ballistic missile defense shield.

The U.S. Missile Defense Agency said the SBX will be at Pearl Harbor for the remainder of the summer for "routine maintenance." It will depart in early fall.

The powerful radar has 45,000 radiating elements within its white pressurized dome and is used to track targets and discriminate nuclear warheads from decoys.

Adak, Alaska, was the radar’s intended home port. Since the "golf ball" arrived here in 2006 from Corpus Christi, Texas, for a temporary stay, it has returned periodically to Hawaii for millions of dollars in maintenance and repairs.

In June 2009 the U.S. military prepared missile defenses around Hawaii and on the mainland as a precaution against a possible North Korean launch across the Pacific.

Defense Secretary Robert Gates also ordered the use of the X-Band Radar, which was in Pearl Harbor at the time.

The radar platform is large enough to fit 18 basketball courts. The radar is so powerful it can detect a baseball flying through the air on the East Coast when the SBX itself is on the West Coast.

In 2003, Pearl Harbor and Kalaeloa were considered as home port possibilities for the SBX, along with anchorages in California, Washington state, the Marshall Islands and two sites in Alaska, before Adak was selected.