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 this is 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 Washington's efforts to pursue a similar strategy in Europe, where the idea has been stalled by the lack of willing partners.
The station here 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, the deputy commanding general of operations for the U.S. Army Space and Missile Defense Command.
In a recent mock-up of how it would work, U.S. 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-world crisis, the next 10 or 15 minutes could be the beginning of an all-out shooting war. Millions could die. Or, two missiles could collide in mid-air over the ocean.
$8 billion sought this year
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 a huge amount of resources — the U.S. Missile Defense Agency is seeking an $8 billion budget this year — into establishing a credible warning and response network.
Though Washington's focus, and world attention, has shifted toward Iran, North Korea has over the past several years 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 — a step that Iran has not taken — and more than a decade ago shot a multistage ballistic missile over Japan's main island and well into the Pacific, almost reaching Alaska.
Japan's concerns are obvious: Its islands arc around the Korean Peninsula, and relations between the communist North and its former colonial ruler have never been good.
But the threat to the United States is also pressing.
Under a mutual security pact, the United States has about 50,000 troops deployed around Japan — all within reach of North Korea's missiles.
The U.S. military last year deployed a Patriot missile battalion to Kadena Air Base, on the southern island of Okinawa. The U.S. and Japanese navies have also increased their ability to intercept ballistic missiles from sea-based launchers.
Japan shoots missile out of air
In a test off Hawaii in December, Japan became the first country after the United States to shoot a missile out of the air with a ship-launched SM-3 interceptor. Japan hopes to equip its ships with such interceptor missiles over next several years.
The sea-based interceptors, which have a longer range than land-based Patriots, are Japan's first line of defense.
Seward said he hopes the alliance with Tokyo on ballistic missile defense will serve as a model for the world.
The U.S. operates its three other JTAGs in Germany, Qatar and South Korea.
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 dismisses U.S. arguments that the installations are meant to counter a potential threat from Iran, saying they believe the intent is to weaken Russia.
Japanese officials admit that they have signed on to Washington's BMD alliance because the urgency of the Asian situation — which may not apply to Europe.
"Around Japan there are countries that could launch ballistic missiles against us," said Ro Manabe, the Ministry of Defense press secretary. "But in Europe, they do not have an imminent threat like that. In the near future, it may be possible that some countries, like Iran, may get that capability. But there are such states currently in this region. That is a basic and significant difference."
Manabe said the dense population of Tokyo makes the establishment of permanent bases inside the city unlikely.
Seward, meanwhile, said that while U.S. missile detection capabilities have vastly improved, it will largely fall to Japan to defend itself in an attack.
"Most assets in Japan are Japanese," he said. "The Japanese would have to defend themselves."