Domed radar platform departs Puget Sound

That odd-looking floating object topped by a dome, which arrived in Puget Sound in May, departed yesterday after three months of maintenance at Vigor Shipyard Seattle (formerly Todd Shipyards).

The sunny weather provided prime viewing for boaters and shoreline observers, as the huge radar platform — called the Sea-Based X-Band Radar, or SBX — moved out of Elliott Bay and up through Puget Sound.

The radar ship is part of the U.S. Ballistic Missile Defense System (BMDS) and is the only vessel of its kind in the world. One of the upgrades during refit was a new electrical system to allow the ship to operate with offshore power instead of running its diesel generators while in port.

The radar that sits on top of an oil-drilling platform is extremely powerful and can cover a huge area, limited mainly by the Earth’s curvature.

“You could put the SBX in the Chesapeake Bay and it could track something the size of a baseball hit outside here from Safeco Field, provided it could get over the curvature of the earth,” Army Col. Mark Arn was quoted as saying on the website after the ship arrived in Seattle. Arn is the Missile Defense Agency’s project manager for the X-band sensors.

In operation, the radar is designed to track missiles in flight, with the ability to distinguish between a hostile missile warhead and decoys, according to a fact sheet (PDF 148 kb) from the Missile Defense Agency and a booklet called “A Brief History of the Sea-Based X-Band Radar-1” (PDF 3.4 mb) Data collected from the radar system can be transmitted to interceptor missiles that are sent out to destroy the incoming missile before it strikes its target.

When the SBX first came in, I wondered what the radar equipment looked like under that white dome, which stands 103 feet high and is made of a synthetic inflatable fabric that apparently can withstand 130-mile-per-hour winds. I found a photo on Boeing’s website that shows the ship under construction and the radar being installed. Click on the Boeing SBX link and click again to see a large version.

The SBX is 240 feet wide and 390 feet long, larger than a football field. It towers more than 280 feet from its keel to the top of the radar dome.

The main deck houses living quarters, workspaces, storage, power generation, bridge, and control rooms, as well as the radar antenna array plus command, communication and data-analysis centers.

The video embedded on this page was produced by Erik Hyypia, a kayaker who paddled a little too close to the docks to get this shot when a patrol boat asked him to move back. The later shots were taken yesterday from Seacrest Park in West Seattle as the platform passed by.

Erik, who works as a senior engineer at the Bill & Melinda Gates Foundation, enjoys taking video in his spare time. His YouTube channel features a variety of kayaking and hiking videos.

One thought on “Domed radar platform departs Puget Sound

  1. We got some photos of it as it passed in front of Pt. Wilson last night (Saturday). A number of people were looking out from the parade grounds at Ft. Worden, and asking aloud, “What IS that thing?!” Reminded me of the youtube video by Steve Martin and Bill Murray (what IS that thing?!)

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