It was starting to look like 2001 again. That year, a Chinese naval fighter chased and hit a U.S. spy plane near its south coast, forcing it to land. The crew was detained for 11 days. Neither superpower was happy, and who could forget that the U.S. and China were Cold War rivals just a few decades ago. The Chinese seizure on Thursday of a U.S. Navy underwater drone that was exploring the widely disputed South China Sea raises the specter of another massive Sino-U.S. spat, even though President-elect Donald Trump loudly tweeted at China: “let them keep it!”
But the discovery of a U.S. drone in a politicized ocean on the other side of the world raises sticky questions that will become ever more relevant as China and the United States square off in the months, or years, ahead. Here’s a list of answers worth knowing: 
(Photo credit: TED ALJIBEAFP/Getty Images)
1. What’s the United States doing with naval drones in the South China Sea? Short answer: military surveillance. Target: China. The drone seized by China is officially called an unmanned underwater vehicle, UUV for short, or “ocean glider” if you like fancier terms. The Pentagon websitesays the vehicle gathers “military oceanographic data” such as salinity, water temperature and sound speed. A U.S. oceanographic survey ship USNS Bowditch responsible for the UUV was conducting “routine operations in accordance with international law” 50 nautical miles (92.6 km) northwest of the Philippines, the Pentagon website adds.
2. Why is United States exploring the South China Sea? The United States, being in another hemisphere, doesn’t claim the South China Sea. China claims about 95% of it, along with Taiwan (and China claims Taiwan itself). Brunei, Malaysia, Vietnam and the Philippines claim parts of the ocean. The United States is an old ally of all but Vietnam, and warmed towards Hanoi last year to help the Southeast Asian country’s resistance against China. In view of those alliances, China has accused the United States of trying to contain its expansion. China cites historical records to back its maritime claim to the 3.5 million-square-km (1.4 million-square-mile) ocean that stretches from Taiwan to Singapore. U.S. officials insist they want only freedom of navigation.
3. Why did China pick up the drone? Chinese officials said a naval lifeboat cleared the drone to ensure safe passage for other vessels. On Sunday the Chinese Ministry of National Defense said the vessel would be returned in an “appropriate manner,” perhaps meaning it would remove any equipment or footage. Or how about this explanation? China sees an American drone, like a spy plane, as an intrusion worthy of expulsion.
4. How does the drone seizure’s fallout impact other South China Sea claimants? Beijing irritates the Southeast Asian governments that call waters in the South China Sea their own by passing ships through their claims and militarizing some of the islets – including seven in the Spratly chain per data from the Center for Strategic and International Studies last week. Although most won’t say as much to avoid upsetting their prized economic ties with China, the other countries are glad the United States is poking around. Malaysia, Vietnam, Taiwan and the Philippines have all looked to Washington as a military benefactor either steadily for decades or here and there as needed. In exchange, the United States maintains a string of allies near China’s coast, part of a containment strategy.
5. What’s going to happen next? The United States will keep passing ships over and under the South China Sea as it has done before. China will “continue to be vigilant” toward undersea activities by the U.S. in South China Sea, its defense ministry army spokesman Yang Yujun told state media in China on Sunday. More Chinese seizures of U.S. military property would prompt the United States to keep up their maritime research work, just more carefully. Experts say to expect vessels from both sides. “It’s very normal for a navy to conduct this kind of operation,” says Alexander Huang, strategic studies professor at Tamkang University in Taiwan. “The more you understand the ocean area that you may operate in the future, then better for your fleet and submarines.”