Each of the two American spacecraft, launched in 1960 and 1964, were metalized balloon satellites acting as passive reflectors of microwave signals.

William H. Pickering, director of Jet Propulsion Laboratory (JPL), also attended the conference and suggested that JPL facilities, specifically a 26 m (85 ft) diameter polar-mounted antenna installed near Goldstone Dry Lake in the Mojave Desert, might be used as a ground facility for experiments with such a satellite.

[4] In October 1958, Pierce, along with fellow Bell engineer Rudolf Kompfner, designed an experiment to observe atmospheric refractive effects using reflective balloon satellites.

Further experiments used the satellite to engage a two-way telephone conversation on 15 August 1960 and to relay a live television transmission in April 1962.

Digital slave worked by receiving primary tracking data from the NASA Minitrack network of stations.

These balloon satellites were approximately 30 m (98 ft) in diameter with a thin skin made of Mylar (a trade name for stretched polyethylene terephthalate or BoPET), and were built by Gilmore Schjeldahl's G.T.

[9] It also had 107.9 MHz telemetry beacons, powered by five nickel-cadmium batteries that were charged by 70 solar cells mounted on the balloon.

Therefore, the balloon was capable of maintaining its shape without a constant internal pressure; a long-term supply of inflation gas was not needed, and it could easily survive strikes from micrometeoroids.

[11] It was inflated to a pressure that caused the metal layers of the laminate to plastically deform slightly, while the polymer was still in the elastic range.

Shotput 1 successfully delivered the Echo prototype to the desired altitude, but a small amount of residual gas in the folds of the balloon violently expanded, bursting the test article.

People up and down the Atlantic coast witnessed what looked like distant fireworks as thousands of pieces of shredded Mylar reflected sunlight in a display that lasted for about 10 minutes.

[2][15] A microwave transmission from the JPL Goldstone facility in California, was relayed by the satellite to Bell Laboratories in Holmdel, New Jersey, that same day.

[8] It was originally expected that Echo 1A would not survive long after its fourth dip into the atmosphere in July 1963, although estimates allowed the possibility that it would continue to orbit until 1964 or beyond.

In addition to passive communications experiments, it was used to investigate the dynamics of large spacecraft and for global geometric geodesy.

Because Echo was only a passive system, it was primarily useful in demonstrating the future potential of satellite communications and became obsolete before it deorbited in 1968.

[5] The Echo satellite program also provided the astronomical reference points required to accurately locate Moscow.

[17] The large horn antenna at Holmdel constructed by Bell Labs for the Echo project was later used by Arno Penzias and Robert Woodrow Wilson for their Nobel Prize-winning discovery of the cosmic microwave background radiation.