In a few weeks will be an historical benchmark--the launch of Echo 1. May 13th, 1960 marks the date of the first passive telecommunication satellite launched by a Delta rocket. This simple balloon-like satellite some 90 feet in diameter was made of mylar polyester film 0.0127 mm thick and lasted a little over eight years. Many a summer night yielded, without the aid of optical instruments, it's trek across the night sky.
Gunter's Space Page