Object crossed the sky like a satellite, but at about 45 degrees from horizon I could notice it was glowing and fading with a period of about 4 seconds. At 90 degrees, just above us, the frequency changed to a higher one and the object glowed twice. The object continued in the same course until it seemed to stop at about 45 degrees from E horizon. I could not see it anymore. As satellites do not glow and fade, or change speed, I presume it was some other device. The time was about half an hour after sunset.It really looked like those glowing dots seen on NASA movies made on ISS.