The published speculation is somewhat non-specific. As to seeing it coming, apparently it was not seen until there was a public outcry. All of this is beyond my expertise.
My main question to you would be: Why would the PRC undertake such a pointless mission? Is it only to demoralize public opinion and intimidate us? WHY didn't the administration choose to take the balloon out by the time that it reached the Aleutians? Why did they allow it to continue to navigate over the continental U.S.? Why wait until it left our territory and then shoot it down and mount a retrieval mission? NORAD admitted that they were not capable of tracking these high altitude slow moving UAVs - the 'picket fence gap'.
And, as I say, the Chinese themselves bragged about the capability of these balloons to effectively carry hypersonic missiles; perhaps that is true, perhaps not.
🤷♂️
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