Spotted this metallic object in the sky (probably 40,000ft altitude) above Portland, Oregon. For roughly 45 minutes, F-15 jets flew around it at various altitudes, seemingly trying to ID the object. I sent a little drone up to 400ft to help give a little bit better perspective on how high up the unknown object was. I am guessing it was some kind of weather balloon – something of that nature. It slowly drifted Southeast until it disappeared into the sun. Nothing super exciting, but I figured s...