Fast moving bright light seen near Portland, OR

Background of ((name deleted)): Over 5000 flight hours.  Currently a captain with ((company name deleted)).  Bachelor’s Degree in Aeronautical Science from Embry Riddle.
Narrative from ((witness name deleted)): Sitting in my hot tub and observed a bright white object go from southwest to northeast. It was traveling at a high speed estimated to be about 5 times faster than a normal jet at cruise and/or 6 times faster than the international space station seen from Earth. The object was at about 10,000 feet and there was cloud coverage with a thin broken ceiling in the background. The object did not appear to show any navigational lights or strobes, apparent on most aircraft. It was also a bright white steady light compared to the more yellowish tint of aircraft. My fiancée also saw the object and noticed it a few seconds before me. She said it was traveling due east and then changed directions to go northeast. She is a flight attendant and originally thought it was a commercial aircraft. About 5 minutes after the object disappeared a commercial aircraft flew overhead and my fiancee was able to notice the difference between what we saw and the commercial aircraft.
 Captian Joseph S Buley