The space shuttle Atlantis docked with the ISS earlier this month and transferred some 6000 pounds of supplies to the station to support the rotating ISS crews. Seen with bare eyes That the ISS and other orbiting satellites can be seen from the ground at all is news to some folks. But the fact is ever since Sputnik 1 in 1957, humans have been able to see these manmade moons as they loop around the earth. While we've watched some of them, they've been watching us too. Spying is a common reason for lofting earth-orbiting satellites.
Earth orbiting satellites become visible when they reflect sunlight.
They generally have no lights of their own that would waste energy. They can become visible right after dark when their orbits carry them through sunlit space some 200 miles or more above us. Likewise, they can be seen before dawn when the sun has risen at that altitude but our sky still appears dark. A few minutes of careful looking from a clear, dark moonless site right after dark will usually show you at least a couple of satellites. They appear as moving points of light, appearing to move about as fast as a high-flying airliner.