For simplicity it would be hard to beat the "balloon" satellites, of which the Echo 1 was the first and most famous. On June 24, 1966, NASA launched singularly perfect specimen, the 100-foot-diameter Pageos, which looks like a giant highly polished ball bearing. Made of Mylar film 0.0005 inch thick, Pageos weighed only 120 pounds and when inflated in orbit was half a million times larger than the canister into which it had been skillfully packed. Moving in a polar orbit at an altitude of 2600 miles it is easily visible to the naked eye.
One doesn't see a lot about satelloons, besides on greg.org, so I was very surprised last night to find Echoe 1 make an appearance in JG Ballard's 1966 book The Crystal World:
Peering upward, he stared into the star filled sky. In front of him , at an elevation of forty-five degrees, he picked out the constellation Taurus and Orion. Passing them was a star of immense magnitude, a huge corona of light orne in front of it and eclipsing the smaller stars in its path. At first Sanders failed to recognize this as the Echoe satellite. Its luminosity had increased by at least tenfold, transforming the thin pinpoint of light that had burrowed across the night sky for so many faithful years into a brilliant luminary outshone only by the moon. All over Africa, from the Liberian coast to the shores of the Red Sea, it would now be visible, a vast aerial lantern fired by the same light he had seen in the jeweled flowers that afternoon. Thinking lamely that the balloon might be breaking up, forming a cloud of aluminium like a giant mirror, Dr. Sanders watched the satellite setting in the southeast.
The money to build the brick moon was raised by public subscription, and the flywheels were constructed in a remote part of the United States. The moon itself was not a simple shell of masonry, but had its interior divided into thirteen spherical chambers, in contact with each other so that "by the constant repetition of arches, we should with the least weight unite the greatest strength." However, things did not go quite according to plan. One night owing to a ground subsidence, the brick moon was accidentally launched together with all the workmen and engineers who decided that its spacious chambers made beter living quarters than their log cabins.