[foofoo55]

The F-22 service ceiling is 60,000 ft so it can get up there too. The U2, however, flies relatively slow (< 400 kn) at that altitude so is ideal for an up-close inspection.

I would think that the U2 internal cameras were designed for a long focal length and for objects below the aircraft. I wonder if they made modifications for balloon photos.

[mulmen]

The U2 contains a far more advanced sensor suite than just cameras. With something like this balloon I suspect the signals intelligence is at least as interesting as any visual reconnaissance.