My dad worked for NASA during the 60's and 70's and we often looked up at the sky at night to look for satellites. The event took place one night as I looked at the sky. I guess I was about 10 years old, I was on our front porch by myself and I spotted a satellite or so I thought. It did not look any different from all the others I had seen, except for the fact that it changed course.
I distinctly remember watching as this speck of light approached another speck of light, which I assume was a star or planet. I realized of course that the satellite is circling the earth and would pass in front of this other speck of light.
That did not happen. The speck of light I thought was a satellite went around the other speck of light. It made a perfect half circle around the planet or star and continued on its original path. My mother was near the door and I called for her to see it. She got to the door in time to see it finishing it's half circle.
Both the star or planet, and what I thought was a satellite seemed to be about the same size. So this UFO had to be about the same size as the planet or star. Also it was moving at about the same speed as a satellite would move across the sky. Given it was on the same plane as the planet or star it had to be moving at an incredible rate of speed to appear to be moving at the same speed as a satellite circling the earth.