On this day, 10 July 1962: Telstar, the first active communications satellite, launches

On the morning of 10 July 1962, a Delta rocket lifted off from Cape Canaveral, Florida, carrying a satellite about the size of a large beach ball into an elliptical orbit around the Earth. That satellite, Telstar 1, would go on to change how the world communicated, becoming the first active satellite capable of relaying television, telephone and data signals across an ocean.

Telstar was built by Bell Telephone Laboratories, the research arm of AT&T, in partnership with NASA and with support from the French national telecommunications agency and the British General Post Office. The project reflected a rare moment of international cooperation built around a shared technical ambition: proving that a satellite could relay live signals between continents in real time.

Unlike a passive satellite that merely reflects signals sent to it, Telstar was active, meaning it received a signal, amplified it, and retransmitted it back down to Earth using an onboard transponder powered by solar cells. This active-relay design became the basic blueprint that most communications satellites would follow for decades afterward.

Just a day after launch, on 11 July 1962, Telstar relayed the first public transatlantic television signal, transmitting images between ground stations in Maine and France and Britain. The early transmissions included test patterns and brief broadcast segments, offering audiences on both sides of the Atlantic a glimpse of a technology that had, until then, existed only in theory.

Telstar orbited the Earth roughly every two and a half hours on an elliptical path, meaning it was only in position to relay signals between North America and Europe for about 20 minutes during each orbit, a limitation that made scheduling transatlantic broadcasts a careful logistical exercise for engineers on both continents.

The satellite's active life was cut unexpectedly short by radiation. A high-altitude US nuclear test conducted the day before Telstar's launch had significantly increased radiation levels in the Van Allen belts surrounding the Earth, gradually damaging the satellite's transistors. Telstar stopped working in November 1962, was briefly revived, and failed permanently in February 1963.

Despite its short working life, Telstar's technical success proved that satellite-based intercontinental communication was viable, paving the way for the geostationary communications satellites that would soon follow and eventually make live global broadcasting a routine feature of modern life rather than a novelty.

The satellite also captured the public imagination well beyond engineering circles. Its launch inspired a wave of media coverage and cultural references at the time, reflecting the sense that instantaneous global communication, once the stuff of science fiction, had suddenly become technically real.

Today, thousands of satellites orbit the Earth carrying television, internet and communications traffic using principles Telstar helped establish, even though the technology itself has advanced enormously, moving from Telstar's brief elliptical passes to satellites that hold a fixed position relative to the Earth's surface.

Telstar 1 itself remains in orbit today, a dead but intact piece of space history, silently circling the planet more than six decades after its brief but transformative months of active service kicked off the modern era of satellite communication.