Extra star in the Dig Dipper flew over the mountains North.

I was lying in bed watching the sky out of a large picture window facing North.  I was looking for the Big Dipper. Part of it was hidden by the roof line, I thought. Some thing looked wrong with it. I realized it had an extra star in it.  About the time I figured it out the extra star started across the sky North and disappeared over the mountains. It traveled at a steady rate of speed slowly enough that I was able to watch it for maybe 20 seconds after it started to move. The craft looked just the same as the other stars in the Big Dipper. Yellow like a light or a star on a clear night. There was no light pollution and no Northern lights that night.  I was so shocked I couldn't sleep and I don't think anybody ever really believed it. It didn't wobble like a sat- ellite or have a tail. I probably watched it 15 or 20 minutes before it went out of sight. No sound.