Country of Origin: United States of America Overall (spacecraft,
inflated): 135 ft. tall x 135 ft. wide, 375 lb. (4114.8 x
4114.8cm, 170.1kg) Mylar polyester, aluminum film During the
late 1950s and early 1960s, researchers considered two possible
technologies for space satellite communications. One was
"active" satellites, designed to receive a signal, amplify it,
and then transmit it back to earth. This technique became the
basis for the communications satellites prevalent today.
"Passive" satellites, such as Echo, were also briefly
considered. This type of satellite only served as a reflective
surface: signals transmitted from the Earth were bounced back to
the ground. While Echo had the advantage of simplicity, active
satellites quickly surpassed the limited range of communications
possible from a reflective surface in space. Echo 1 was launched
in 1960 and Echo 2 in 1964. By the time of the second Echo,
active communications satellites had clearly demostrated their
much greater capabilities and the passi