the operational envelope
中国がdroneを開発し、所有していたとは驚きの一言です。operational envelopeは「動作範囲、動作領域」という意味でゲームなどでもおなじみのフレーズです。envelopeの意味合いを一度詳しくチェックしておいてください。（GP）
Hacking U.S. Secrets, China Pushes for Drones
The drone appeared to be a BZK-005, a long-range aircraft used by the Chinese Navy that made its public debut in 2006 at China’s air show in Zhuhai, said an American official.
Mr. Easton said deploying the drone near disputed waters and islands “was very much a first” for China and had caught Japanese officials off guard.
“I think this is really just the beginning of a much broader trend we’re going to see — for China to increase its ability to monitor the East China Sea and the Western Pacific, beyond the Philippines, and to increase the operational envelope of their strike capabilities,” he said.
The Chinese military, with its constant focus on potential war over Taiwan and an eye on China’s growing territorial disputes, is at the vanguard of preparing drones for use in maritime situations. That is unlike the United States, which has used drones to hunt and kill suspected terrorists and guerrilla fighters, mostly in Pakistan and Afghanistan.
American drones “are not designed to enter into contested or denied air space,” Mr. Easton said. “So they would be unable to fight in any conflict with China.”
China, on the other hand, is building drones, also called unmanned aerial vehicles, precisely to operate in contested spaces. “It’s a very useful instrument for safeguarding maritime sovereignty,” said Xu Guangyu, a retired major general and director of the China Arms Control and Disarmament Association. “China will gradually step up its use of U.A.V.’s in this area.”
