One of only four in the world, the Joint Tactical Ground Station sits in a field of snow behind the high fences of this remote base in northern Japan like a windowless trailer home with a few good satellite dishes out back.
It's not impressive. But it's the front line.
In a multibillion-dollar experiment, Japan and the United States are erecting the world's most complex ballistic-missile defense shield, a project that is changing the security balance in Asia and has deep implications for US efforts for a similar strategy in Europe, where the idea has been stalled.
The station here – the US operates three other JTAGs in Germany, Qatar, and South Korea – is the newest piece in the shield. "Japan is one of our strongest allies in the ballistic missile defense arena," said Brig. Gen. John E. Seward, deputy commanding general of operations for the US Army Space and Missile Defense Command.
In a recent mock-up of how it would work, US military satellites detect a flash of heat from a missile range in North Korea and within seconds, computers plot a rough trajectory across the Sea of Japan that ends in an oval splash-zone outlined in red near Japan's main island.
In a real crisis, the next 10 or 15 minutes could be the beginning of an all-out war. Millions could die. Or, two missiles could collide in midair over the ocean.
Washington and Tokyo are banking on the idea that early warning of the kind provided by the Joint Tactical Ground Station, or JTAG, and another state-of-the-art "X-band" radar station recently deployed nearby will lead to the latter. They are pouring resources – US Missile Defense Agency is seeking an $8 billion budget this year – into establishing a credible warning and response network.
North Korea has made major strides in its development of both nuclear weapons and the means to deliver them to the shores of other countries. In October 2006, it conducted its first nuclear test, and more than a decade ago, it shot a multistage ballistic missile over Japan's main island and well into the Pacific.
Japan's islands arc around the Korean peninsula. The US has some 50,000 troops deployed around Japan.
General Seward said he hopes the alliance with Tokyo on ballistic missile defense will serve as a model for the world. But Washington's efforts to deploy missile interceptors in Poland and a radar in the Czech Republic have deeply frayed ties between NATO and Moscow, which argues that the intent is to weaken Russia.