The substructure beneath the Chinese spy balloon, believed by officials to be the steering and surveillance apparatus, is roughly 90 feet, according to a defense official. That's roughly the length of three city buses.
The balloon carrying that substructure is significantly larger and taller, the source said.
Earlier Thursday, Pentagon spokesman Brig. Gen. Patrick Ryder said the balloon has a "large payload underneath the surveillance component." He compared it to a basket under a blimp.
In terms of size, Ryder had said the balloon is big enough that officials are worried about potential debris possibly hurting people on the ground if the US were to shoot it down.