Very high altitude object makes sharp 90 degree left turn then disappearsAt 6:50pm on 01-05-09 in eastern sky over SC, I saw a dim steadily lit object traveling from N to S at a steady rate, not extremely fast, but sort of fast for the apparent altitude it appeared to be at. I estimated the altitude to be around 50,000ft. or more. It was about 45 degrees up from the horizon. It's brightness was that of an average star just visible to the naked eye. It was nearly directly East when I saw it. It traversed N to S only 5 or so degrees in 10 seconds. I start thinking to myself here is another one! So,I am thinking, I wonder if they know I see them? So I say outloud: "Do something, change speed, change direction, do something" and I'll be danged if it didn't slow down to a crawl, then makes a perfectly short sharp 90 degree radiused turn to the E at its original speed and I watch it for about 5 seconds more before I can no longer make it out. The sky overhead is overcast, but not in the East at that time.Then, 12 minutes later at 7:02pm what sounds like a flight of two to three F-15's comes flying overhead from the NE to the SW, on what could have been an intersecting path with the 'UFO' at some point. The flight sounded like it was approx. 15,000ft or less when it went overhead. That flight was probably on landing approach to Shaw AFB as it only about 30 miles from where I was.