>A Notice to Airmen (NOTAM) has been issued for Kwajalein Atoll in the Marshall Islands, warning of a severe radiation hazard.
Space Fence surveillance radar site declared operational
The $1.5 billion Space Fence can track tiny objects in low Earth orbit as small as a marble.
March 28, 2020
The $1.5 billion Space Fence — located on Kwajalein Island in the Republic of the Marshall Islands — is a ground-based radar system that tracks satellites and space debris primarily in low Earth orbit.
https://spacenews.com/space-fence-surveillance-radar-site-declared-operational/
The World’s Most Advanced Radar
In March of 2020 the United States Space Force (USSF) declared operational acceptance and initial operational capability of the Space Fence radar on the Kwajalein Atoll in the Republic of the Marshall Islands.
Space Fence, now the world’s most advanced radar, provides uncued detection, tracking and accurate measurement of space objects, including satellites and orbital debris, primarily in low-earth orbit (LEO). The new radar permits the detection of much smaller microsatellites and debris than current systems.
https://www.lockheedmartin.com/en-us/products/space-fence.html
How Things Work: Space Fence
The new S-band phased-array radar will have tens of thousands of transmitters and hundreds of thousands of receivers, supported by structures capable of withstanding seismic activity. One of the largest S-band arrays in the world, the receiver alone measures 7,000 square feet. The transmitter is 2,000 square feet. Both will be enclosed in buildings with roofs of electronically transparent Kevlar. Within each element, gallium nitride semiconductors amplify the radar’s power. In a phased array, the elements can be pulsed separately, so the installation will be able to simultaneously search for and track individual objects.
Airspace above the array will be restricted to air travel, though the radar is expected not to harm birds because exposure times will be short, though personnel will monitor bird activity.
https://www.smithsonianmag.com/air-space-magazine/how-things-work-space-fence-180957776/