What Was the Chinese Spy Balloon Trying to Collect?

WASHINGTON — The U.S. government is combing over a variety of intelligence — debris, reconnaissance plane photos and old observations — to learn what the Chinese spy balloon was after as it made its way across the United States in early February, before being shot down by a Sidewinder missile fired by a stealth fighter jet last weekend.

The Chinese spy balloon was equipped with an antenna meant to pinpoint the locations of communications devices and was capable of intercepting calls made on those devices, according to declassified intelligence released by the State Department on Thursday.

The balloon, which traversed America for several days, transfixed the public and focused attention both in Washington and across the country on the intensifying rivalry between China and the United States.

In the wake of the discovery of the balloon, Secretary of State Antony J. Blinken canceled a planned trip to Beijing. China, perhaps in retaliation, rebuffed attempts by Lloyd J. Austin III, the defense secretary, to call his Chinese counterpart to discuss the spy balloon, further raising the temperature of an already tense relationship between the world’s two superpowers.

Here is what we know about the balloon.

What was the spy balloon collecting?

This is the big question. Officials do not yet know what information the balloon was supposed to be stealing as it made its way across the country.

The balloon had a signals intelligence array — fancy spy speak for an antenna that can locate communications devices and listen into them. But officials do not yet know if that array was meant to gather calls made on military radios or from ordinary mobile phones or something else altogether.

How many spy balloons have there been?

Balloons are hard to pick up on radar. Many of the first Chinese spy balloons that were observed near U.S. military exercises or bases were not identified as surveillance tools. Instead, they were classified as unidentified aerial phenomena, modern-day Pentagon jargon for U.F.O.s.

Over the past 18 months, the United States began learning more about the Chinese spy balloon program. As officials reviewed some previous cases of unidentified aerial phenomena, they determined that they were spy balloons. A review of the old data showed that at least three spy balloons entered U.S. airspace during the Trump administration. There was at least one additional visit during the Biden administration.

But all of those previous incidents were relatively short — not the dayslong transit of this month’s spy balloon.

Was this part of a wider Chinese surveillance program?

China has developed a spy balloon program as a complement to its fleet of reconnaissance satellites, American officials said, with a mission to collect information across the world.

Because the capabilities of the spy balloons are not yet perfectly understood, it is not certain if they gather different information than China’s satellites. Nevertheless, officials said, at the very least the balloons can linger longer over a site than a satellite. And while reconnaissance satellites are often focused on imagery, the balloons appear to be mostly about collecting communications.

Some officials say the spy balloon program has been focused in the Pacific region, collecting information on American bases and allied military operations.

And of course, the Chinese do not just use balloons to conduct surveillance at military bases. Some classified reports suggest they are also using advanced technologies to collect information about the U.S. military.

Is this a big deal or not?

Yes.

To be clear, the balloon saga is not comparable to an earthquake in Turkey that killed more than 20,000. Nor is it comparable to the war in Ukraine that is set to enter into a second year.

That said, the spy balloon incident will complicate the relationship between the two most powerful countries on Earth.

Some policymakers and lawmakers in Washington have been arguing for years that the U.S. public has not taken the challenge of China seriously enough — prioritizing the country’s cheap mobile phones and entertaining videos on its platform TikTok over concerns about an authoritarian state that bolsters its power through the intrusive surveillance of its people.

But the balloon ordeal was a big enough deal for the State Department to cancel Mr. Blinken’s planned trip — the first by a Biden cabinet secretary to Beijing — without rescheduling it. When he canceled the trip, Mr. Blinken said the entry of the balloon was a “clear violation of U.S. sovereignty and international law.”

What is the plan for recovering debris?

Navy divers have been working to gather debris of the balloon since Sunday for America’s own intelligence-gathering purposes, Pentagon and F.B.I. officials said. The recovery effort is expected to take days.

The balloon itself was quickly retrieved, as well as some wiring that was floating on the ocean surface. But most of the electronics were in the balloon payload, carried underneath. The remains of that are scattered across the ocean floor, albeit in the relatively shallow waters off the South Carolina coast.

The dive teams are handing over the recovered material to the F.B.I., which will take it to its lab in Quantico, Va. What state it will be in, and how much can be learned from it, remains an open question.

What happens next?

The Biden administration has continued to declassify and share information it has learned about the spy balloon, bringing in allied and partner nations for briefings about China’s surveillance programs.

The diplomatic push is a sign that the Biden administration intends to use the incident to rally allies and convince them that China’s global ambitions could involve infringements of their sovereignty.

Beijing was angry over the United States’ decision to shoot down the balloon, which the Chinese Foreign Ministry described as “excessive.” China has maintained that the balloon was a civilian device for meteorological purposes.

Points of friction between Beijing and the United States are becoming increasingly common. China fired a barrage of missiles in the wake of last year’s visit to Taiwan by House Speaker Nancy Pelosi. Representative Kevin McCarthy said before succeeding her this year that he would also like to visit the self-governing island, which China considers its territory.

Katie Rogers and Zolan Kanno-Youngs contributed reporting.