Echo had the advantage of simplicity, but active satellites quickly surpassed the limited range of communications possible from a reflective surface in space. The satellite was nicknamed a "satelloon" (satellite-balloon), and kids could write in and request small portions of Its metalized skin as a souvenir. I still have a piece stashed away somewhere in the house.
Echo 1 Communications Satellite
The Echo satellites were large metallized balloons that served as passive reflectors of radio signals. Echo 1A was launched on 12 August 1960 and Echo 2 on 25 January 1964. When inflated, Echo 1A was a 100 foot sphere; Echo 2 was a slightly larger 135 feet.