Jessica MacNeil
EDN
On this day in tech history, Echo 1A, NASA's first successful communications satellite, was launched from Cape Canaveral.
The launch followed on a similar but unsuccessful attempt by NASA in May 1960 to launch a near identical satellite. The failure of the launch vehicle for that satellite, Echo 1, snuffed its mission.
Now commonly referred to as Echo 1, Echo 1A was designed as a passive communications reflector to relay transcontinental and intercontinental telephone, radio, and television signals between points on Earth.
A few hours after its launch, Echo 1A relayed its first message, reflecting a radio signal from California to Bell Labs in New Jersey. The message was an address from US President Eisenhower in which he said, "The satellite balloon, which has reflected these words, may be used freely by any nation for similar experiments in its own interest."
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| Echo 1 inflated in a Navy hanger. Photo: NASA | ||
Measuring 100 feet in diameter, the satellite was based on a balloon design and made of a 31,416-square-foot sheet of mylar polyester film 0.0127-mm thick. The sheet was covered with 4 pounds of reflective aluminum coating, and the whole spacecraft weighed 132 pounds.
Nicknamed a "satelloon," it was launched into orbit and then residual air inside expanded it.
It had 107.9-MHz beacon transmitters powered by five nickel-cadmium batteries charged by 70 solar cells mounted on the balloon.
The spacecraft collected data for the calculation of atmospheric density and solar pressure and was used to evaluate the technical feasibility of satellite triangulation, which would improve mapping precision.
The balloon was large enough to see with the naked eye, and NASA released daily schedules telling when and where the sphere could be seen overhead. Amateur ham radio operators were able to bounce signals off of it.
After laying the groundwork for modern satellite communications, the Echo 1A re-entered the atmosphere and burned up on May 24, 1968.
NASA continued with Project Echo, launching Echo 2, a similar but larger satellite balloon than Echo 1A, in January 1964.
