It isn't that hard to see satellites in the sky. The ISS, in particular, can be very bright, to the point where you can see it in daylight (http://www.hobbyspace.com/SatWatching/, http://blogs.crikey.com.au/planetalking/2009/06/18/how-to-se...)

The 1950 ones would have been a lot harder to spot, of course, but might at times have reflected the light of the below-the-horizon sun.