WASHINGTON — If a U.S. negotiating team in China can’t repossess a downed EP-3E plane there, the Pentagon will be left wondering whether the Chinese military gained clues to ultra-secret missile-monitoring technology aboard the surveillance aircraft, defense experts say.

The EP-3E Aries II plane, stranded on the tarmac of a Hainan, China, military airport, ranks among the most secret pieces of equipment in the Pentagon’s arsenal.

The $80 million aircraft, one of only a dozen or so owned by the Navy, is loaded with state-of-the-art radio receivers and high-gain dish antennae that can pick up, record and analyze — using on-board computers running highly classified software — electronic emissions, or signals, from deep within China’s territory. The technology is called radar

All this is well-known. What has not been widely reported, if at all, is that the EP-3E has the added ability of monitoring the flight path — in 3-D — of a missile. The sophisticated technology is called missile telemetry.

“It takes a special sort of aircraft to get missile telemetry intelligence, and if the Chinese were able to pry that technology away, they’d have a pretty nice trophy indeed,” said a former Navy officer familiar with the EP-3E technology.

The officer, who asked not to be identified by name, suspects the EP-3E’s ability to monitor missile launches — particularly ones from submarines — off the China coast is what has provoked such a violent reaction from the Chinese military to recent U.S.
reconnaissance flights over the South China Sea.

“Sub-launched missiles would certainly be something they would want to hide,” he said.

China has been testing a new submarine that has the ability to launch missiles such as the Sunburn — which can knock out U.S. aircraft carriers — while submerged in the South China Sea.

“There’s a significant submarine squadron based in Hainan,” said Rick Fisher, a Chinese military expert with the Jamestown Foundation here.

“Detailed knowledge of their ability to launch submerged missiles — probability rates included — would be important to any [American] carrier commander’s order of battle in defending the Taiwan Strait,” the Navy officer said.

Communist China, which has threatened to use force against Taiwan, has been beefing up its missile forces near the independent island, which has a democratic government.

If China is able to figure out how the U.S. monitors its missile launches, it may be able to counter that technology.

“If this plane has been seriously compromised, there is a significant damage to regional and national security,” the officer said.

Defense Secretary Donald Rumsfeld has said that the EP-3E crew was not able to destroy all equipment and computer programs aboard the aircraft before Chinese military authorities took control of it.

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