What is the suspected Chinese spy balloon flying over Montana?

The US military was closely tracking a huge, high-altitude balloon from China as it sailed across the country on Friday — sparking a spying saga that led to Secretary of State Antony Blinken abruptly postponing a high-stakes Beijing trip.

The “maneuverable” balloon was first spotted Tuesday, has already traveled over sensitive military sites — and is expected to remain in American airspace for several more days, US officials say.

While China tried to claim the balloon was just a weather research “airship” that had blown off course, the Pentagon was quick to reject that claim — dealing a new blow to already strained relations between Washington and Beijing.

Here’s what we know about the Chinese balloon so far:

What is a spy balloon?

Spy balloons are, simply put, a surveillance device.

The one discovered over the US in recent days is a Chinese high-altitude balloon that is flying over sensitive sites to collect information, US officials have said.

The balloon is “maneuverable” and is capable of changing course, Air Force Brig. Gen. Patrick Ryder revealed at a Pentagon press briefing Friday.

He wouldn’t say precisely how the balloon was powered or who in China was controlling its flight path.

The balloon has a “payload” of surveillance equipment hanging from it, but there was no evidence of any nuclear or radioactive contents, Ryder added.

Where is it in the US now?

The balloon had moved eastward and was over the central United States as of midday Friday, Pentagon officials said.

Moments later, Sen. Roger Marshall (R-Kan.) tweeted that the balloon was over northeastern Kansas. Other sightings of the balloon were reported across the state of Missouri Friday afternoon, beginning in the Kansas City metro area and continuing through the city of Washington, about 50 miles west of St. Louis.

The balloon was previously tracked over Alaska’s Aleutian Islands and northwestern Canada.

On Thursday, the balloon was spotted over the state of Montana, which is home to one of America’s three nuclear missile silo fields at Malmstrom Air Force Base.

A US official said the flight path would likely carry the balloon over a number of sensitive sites, but did not elaborate further.

How high is it?

As of Friday afternoon, the balloon was at an altitude of about 60,000 feet, well above the limit for commercial air traffic.

The object does not present a military or physical threat to people on the ground, Ryder said.  

How big is the spy balloon?

US defense officials haven’t specified the exact size of the huge balloon but have said it is large enough that, despite its high altitude, it can be seen from the ground with the naked eye.

“The public certainly has the ability to look up in the sky and see where the balloon is,” Ryder said after declining to provide ongoing updates on the balloon’s exact location.

Sen. Marco Rubio (R-Fla.) tweeted Friday morning that the balloon “has a large payload of sensors roughly the size of two city buses.” ABC News, citing a senior defense official, reported Friday the device was the size of “three buses.”

Why hasn’t the US shot it down?

The US military opted not to shoot down the balloon because of the safety risks to people on the ground given the size of the payload and potential for debris, officials said.

A senior defense official said the US had scrambled fighter jets, including F-22s, to shoot it down if ordered — but President Biden accepted the Pentagon’s recommendations to let the balloon be.  

On Friday, Ryder declined to rule out shooting down the device if it heads out over open water, saying the US would “review our options.”

What has China said?

China initially said the balloon was a civilian airship used mainly for meteorological research that had strayed into US airspace after being blown off course.

US officials, however, say they have “very high confidence” the balloon was being flown over America to collect information due to its maneuverability.

Are balloon sightings common and what’s uncommon about this one?

Balloon sightings happen with some frequency.

In its January report on Unidentified Aerial Phenomena — Pentagon jargon for UFOs — the Defense Department noted 163 of 366 reports (or 44%) could be “characterized as balloon or balloon-like entities,” though it’s unclear where the entities were spotted and from what countries they came.

While this is not the first time a foreign spy balloon has floated through American airspace, there are several reasons why officials say this one stands out.

First, the timing of the balloon’s flight is curious, as one State Department official noted: “This is the first time it’s happened on the eve of a planned secretary of state visit” to China. 

It was also spotted the same week the US confirmed a deal to increase its military presence in the Philippines, placing pressure on neighboring China and bringing US forces closer to Taiwan. 

What don’t we know about the balloon?

Aside from saying there is “a surveillance capability underneath” the balloon, it’s unclear exactly what the object can do — and is doing. A senior defense official claimed Thursday it is unlikely the balloon has any better data collection ability than a Chinese satellite — leaving open the question of why the balloon was sent across the Pacific in the first place.

However, other experts have said the balloon could be carrying a camera to get a closer look at sensitive US military locations — or sensors to pick up encrypted communications or other intelligence.

“We shouldn’t let this thing be floating above our ICBM fields, or really over the U.S. in general,” Tom Karako, director of the Missile Defense Project at the Center for Strategic and International Studies, told National Public Radio. “It’s hard for me to believe that if we were putting a balloon over China and they had the capacity to take it down, that they wouldn’t do so.”