Launched on July 10, 1962, Telstar 1 was NASA and AT&T’s ambitious endeavor to place a telecommunications satellite in orbit to transmit live television signals between the U.S. and Europe. It was by no means the first communications satellite — that title belongs to ARPA’s (DARPA’s precursor) SCORE), which fell back to Earth after a few short months due to its design flaws and shallow Earth orbit. SCORE was also outfitted with a passive reflector that greatly reduced signal strength and could only broadcast voice signals.

The Telstar project, on the other hand, received extensive financial backing to advance satellite communication technology and create a fully functioning ground station to receive and transmit satellite telecommunication signals. AT&T reportedly invested $1.4 billion for research and development of the hardware needed for the endeavor.

Telstar wouldn’t reflect signals back to Earth. It was active, meaning it had to receive the signal, process it, amplify it, and retransmit it back to a ground station. Such a feat didn’t yet exist, so engineers set out to make that hardware a reality.

What Went into the Telstar 1?

Telstar 1 was relatively small by today’s standards, measuring just 34.5 inches in diameter and weighing about 171 pounds, a paltry weight considering it was launched into orbit atop a Delta rocket. Packed inside was a transponder with a 50-MHz bandwidth that could relay a single television channel or a frequency division multiplexing (FDM) signal containing multiple telephone calls or data streams.

It also featured two rings of microwave cavities that acted as uplink and downlink antennas for the data signals. The satellite could receive a 6.39-GHz microwave uplink signal from the transmitting ground station through the upper ring of smaller cavities, and transmit a 4.17-GHz downlink signal back to the receiving ground station via the lower ring of larger cavities.

Because the transmitter was very weak and ran on just 14 W, very large aperture antennas were required at the ground station just to communicate with it. Telstar 1 drew its power from 3,600 solar cells placed around the spacecraft’s hull. A traveling wave tube amplifier (TWTA) was used to magnify the signal strength of the active repeater to transmit and receive television signals, telephone calls, telegraph signals, facsimile transmissions, and data transmissions.

Telstar 1 wasn’t a geostationary satellite; it traveled an elliptical medium Earth orbit, rather than sitting above one location on the planet. As a result, communications could only take place while the satellite was in the right position over the Atlantic and had a communication window of about 18 minutes per pass.

Transmitting TV Images

While in orbit, engineers instantly began testing the satellite’s capabilities. Just hours after launch, it transmitted television images between the United States and France. One of the first images was an American flag outside the Andover ground station in Maine, which was received at the Pleumeur-Bodou station in France.

Those first televised images were groundbreaking, as television could now show viewers events around the globe almost while they happened. As a testament to that notion, several hundred million people across 16 countries tuned in to portions of the first public broadcast, which included images of the Statue of Liberty and Eiffel Tower.

But alas, as groundbreaking as it was, the satellite had a short life and only remained active for seven months. While the satellite was packed at the time with cutting-edge technology, it had no shielding against radiation. Telstar 1 encountered radiation after prematurely failing due to Starfish Prime, a high-altitude nuclear detonation test by the U.S. military in 1962. Thus, Telstar stopped responding to ground commands on November 23, 1962, briefly came back to life in January 1963, and then went permanently silent on February 21, 1963.

Final Thought

Telstar 1 may have only existed a few months, but its impact lasted much longer. The satellite proved that an active communications system could be placed in orbit and used to transmit television, telephone calls, and other data across the Atlantic in near real-time.

Though Starfish Prime ultimately helped bring Telstar 1 to an early end, the lessons learned from its failure helped engineers build better-protected satellites for the future. In the end, Telstar 1 was a short-lived experiment that helped lay the foundation for the global satellite communications networks we rely on today.