by: Charles Q. Choi
August 19, 2010
1st Communication Satellite: A Giant Space Balloon 50 Years Ago
People on Earth may take for granted today’s high-tech world of cell phones, GPS and the satellites high above the planet that make instantaneous communication possible. But it all began 50 years ago with one giant space balloon.
Echo 1, the world’s firstcapable of relaying signals to other points on Earth, soared 1,000 miles (1,609 km) above the planet after its Aug. 12, 1960 launch, yet relied on humanity’s oldest flight technology — ballooning.
Launched by NASA, Echo 1 was a giant metallic balloon 100 feet (30 meters) across. The world’s first inflatable satellite — or “satelloon,” as they were informally known — helped lay the foundation of today’s satellite communications.
“Instantaneous global telecommunications fundamentally altered our lives, and this was the beginning of it,” said former NASA chief historian Roger Launius, a senior curator in the space division at the Smithsonian Air and Space Museum in Washington, D.C.
A true communications satellite
The idea behind a communications satellite is simple: Send data up into space and beam it back down to another spot on the globe. Echo 1 accomplished this by essentially serving as an enormous mirror 10 stories tall that could be used to bounce communications signals off of.
While, Echo 1 was not the first satellite to broadcast a message from space (a recorded Christmas greeting from President Dwight Eisenhower was transmitted in December 1958 during the Project SCORE satellite test), it was the first to facilitate two-way, live communications.
Echo 1 was made of a 31,416 square-foot (2,918 square-meter) sheet of Mylar plastic film only 12.7 microns thick, or roughly one-tenth the width of a human hair. That sheet was covered smoothly with 4 pounds (1.8 kg) of reflective aluminum coating. Altogether, with inflating chemicals and two radio tracking beacons powered by five storage batteries and 70 solar cells, the balloon weighed just 132 pounds (59.8 kg).
The satellite now commonly known as Echo 1 was actually formally named Echo 1A. The original Echo 1 was destroyed after a failure in the rocket designed to launch the giant ball into space, which scientists had dubbed Shotput.
More than a giant space balloon
Among Echo 1’s many contributions was the first live voice communication via satellite, delivered by none other than President Eisenhower himself.
In the radio message, Eisenhower said, “This is one more significant step in the United States’ program of space research and exploration being carried forward for peaceful purposes. The satellite balloon, which has reflected these words, may be used freely by any nation for similar experiments in its own interest.”
The first coast-to-coast telephone call using a satellite was also made with Echo 1, from one researcher to another as a test, as was the first image transmitted via satellite: a portrait of Eisenhower.
The giant, silvery balloon was large enough to see with the naked eye over most of the Earth, proving brighter than most stars, and was used to help broadcast radio transmissions across continents.
“Amateur ham radio operators played around with it by bouncing signals off,” Launius told SPACE.com.
Incidentally, to communicate with Echo 1, Bell labs created a 50-foot (15-meter), horn-shaped antenna. Later, while calibrating the antenna, radio astronomers Arno Penzias and Robert Wilson detected, the first solid evidence of the Big Bang, for which they won the Nobel Prize.
The satellite also proved useful in calculations of atmospheric density and solar pressure.
The spacecraft proved remarkably durable, surviving a meteor shower. Still, it proved susceptible to sunlight, which could shove it around, enough to push it back into Earth’s atmosphere. It burned up on re-entry on May 24, 1968.
Although NASA sent up a second Echo satellite for more experiments, it ultimately chose satellites that could actively transmit data, rather than passively reflect signals.
Still, inflatable spacecraft are now making a comeback.
The Las Vegas-based company Bigelow Aerospace is developing private inflatable space habitats with the goal of launching the first private space station in 2014. The firm has already launched two prototype modules into space.
“Echo 1 was an intriguing experiment,” Launius said.