Observed what appeared to be a dim satellite make a U-turn, then accelerate to an unbelievable speed.At approximately 9:00 PM on the evening of October 16th in Portland Oregon I observed what I took at the time as a satellite moving in a Northwest direction. One of my hobbies is Astronomy so I often look up to the heavens. I've seen the Space Station, Mir, Space Shuttles, Sky Lab and countless Satellites. This Satellite was different though. It had all the characteristics of being a Satellite, such as altitude, flying in a straight line and speed equivalent to that of a Satellite. What I though odd about this object was that is was quite dim, which made it hard to visually track. I wondered why, being it was so high in the sky, didn't reflect the sun off of it? It most definitely had the altitude for the reflection. I kept watching it for about 12 seconds and then it did something I have never in my life seen a Satellite, or anything else do, it made a U-turn, angled itself upward at about a 40 degree angle, maintained it's speed for 4 more seconds and then it accelerated to a speed I don't think you could put in miles-per-hour. All I saw was a streak leave the area where it was cruising at the speed of a Satellite. Get's you to thinking, doesn't it?((NUFORC Note: If the estimate of the direction is correct, the object traveling to the northwest could not have been a satellite. Altitude is impossible to estimate accurately without the aid of triangulation. PD))