Both Echo satellites were built by NASA as part of the first experimental communications satellite. Each device was a passive satellite balloon, which allowed the metallized surface reflection of radio waves. Two points on the surface of the earth could well be linked via a rebound on the satellite. Following the loss of Echo 1 (failure of Delta launch vehicle, May 13, 1960), Echo 1A (often known as Echo 1) was launched and placed in low Earth orbit August 12, 1960. The balloon 100 feet in diameter (30.1 m) had an envelope of Mylar (PET) foil with a thickness of 0.127 mm. He allowed the transmission of intercontinental telephone, radio and television. From the ground, Echo 1A appeared brighter than most stars. He returned and was consumed in the air May 24, 1968. Echo 2 balloon was a Mylar foil of 41.1 meters in diameter with the inflation system was enhanced to make the surface smoother and more spherical. He was put into orbit January 25, 1964 by Thor Agena launch vehicle. It was used for communications purposes, and to study the dynamics of spacecraft and geodesy. NASA abandoned passive communications systems after Echo 2. The ball went back into the atmosphere June 7, 1969. The Echo program provides points of reference for the precise location of the city of Moscow, made necessary by the development of intercontinental ballistic missiles [1]. Copyright Text is available under Creative Commons Attribution Share-Alike, other conditions may apply. See Terms of Use for more details, credits and graphics. If reused texts of this page, see how to cite authors and include the license. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc.., Charitable organization governed by section 501 (c) (3) tax United States.

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