Before communications satellites started beaming signals to enable international TV broadcasts, electronic credit card transactions, even email and social media, there was the Synchronous Communications Satellite program, or Syncom.
Launched in the early 1960s and consisting of Syncoms 1, 2 and 3, the program laid the groundwork for today’s massive geosynchronous communications satellites. Back then, though, it existed as a small experimental spacecraft program operated out of Hughes Aircraft Co., founded by reclusive billionaire Howard Hughes.
Harold Rosen, a Hughes electrical engineer, brought the idea for the geosynchronous satellite to fellow engineer Thomas Hudspeth and former Hughes employee Donald Williams, a mathematician. The idea was to create a satellite that could transmit signals to anywhere on Earth. Before Syncom, non-geosynchronous communications satellites required large swiveling antennas on the ground and expensive tracking computers to stay in contact with the satellites during the brief time they passed over a given point on the planet. In contrast, geosynchronous satellites remain at fixed equatorial points and follow Earth’s rotation. Rosen theorized that if three of these satellites were placed in geosynchronous orbit, about 36,000 kilometers above Earth’s equator, they could remain in a constant line of sight with one another and send signals to anywhere on the planet.
A geosynchronous orbit is one in which the orbital period of a satellite matches the time it takes Earth to complete one revolution along its rotational axis. In other words, the satellite completes one orbital revolution in 24 hours.
Resembling a large snare drum, Syncom 1 weighed about 35 kilograms and was covered in dark blue solar cells. The satellite lifted off aboard a Delta rocket from Cape Canaveral, Florida, on February 14, 1963. The launch went flawlessly, and the rocket easily climbed to a transfer point where it reached geosynchronous altitude. Then the apogee motor kicked in for a 22-second burn. A second before burnout, all communications stopped.
A Los Angeles Times article about Rosen’s life said he thought the apogee motor might have exploded. “We were devastated,” Rosen said in the article. The team got to work on several modifications and tried again with Syncom 2, which launched July 26, 1963, from Cape Canaveral.
“Rosen and the other team members waited in a bunker near the launch pad,” the article said. “Again, the launch was flawless. Five and a half hours later, the apogee motor lit. Seconds ticked away. The signals continued without interruption, and the room erupted in cheers.”
The satellite was placed over the Atlantic Ocean and Brazil at 55 degrees longitude. Although the period was 24 hours and the spacecraft remained at a nearly constant longitude, its orbit was inclined at 33 degrees. So, while the satellite had attained a geosynchronous orbit, it had not achieved a true geostationary orbit but moved in an elongated figure eight pattern, 33 degrees north and south of the equator, according to NASA’s description of the Syncom program.
Syncom 2 began regular service on August 16, 1963. Voice, teletype, facsimile and data transmission tests were successfully conducted between the Lakehurst, New Jersey, ground station and the USNS Kingsport, a cargo ship, while it was moored off the coast of Africa. Television transmissions were relayed successfully from Lakehurst to the Telstar ground station at Andover, Maine.
Also in August, with the Kingsport acting as a relay station in Lagos harbor, Nigeria, a phone call was placed between President John F. Kennedy and Nigerian Prime Minister Abubaker Balewa. This would mark the first satellite phone call between two heads of state.
Syncom 3 launched from Cape Kennedy, Florida, on August 19, 1964, and became the first true geostationary satellite over the equator. The satellite famously enabled the live broadcast of the opening ceremonies of the 1964 Summer Olympics in Tokyo, which became the first continuous TV broadcast across the Pacific.
Syncoms 2 and 3 were maintained by NASA until January 1, 1965, when operations were transferred to the U.S. Department of Defense (DOD). The two satellites operated until 1966, providing phone service home for U.S. troops in Vietnam, the Times said.
Although they no longer function, all three Syncom satellites were believed to be orbiting Earth as of May 2025, according to the online satellite-tracking sites space-track.org and N2YO.com.
Spacecraft and Subsystems
The Syncom satellites were cylinders 71 centimeters in diameter and 39 centimeters tall, according to NASA. The fully fueled mass of the spacecraft was 68 kilograms. The nozzle of the solid propellant apogee motor (454-kilogram thrust designed to impart a velocity increase of 1,431 meters per second) extended from the bottom of the cylinder and a coaxial slotted array communications antenna from the top. The total height, including the nozzle, was 64 centimeters. The radial exterior was covered with silicon solar cells, which provided direct power of 29 watts for the 99% of the time the spacecraft was in sunlight. Nickel-cadmium rechargeable batteries provided power when the spacecraft was in Earth’s shadow. No active thermal control was required. Most of the central interior of the spacecraft consisted of the tanks and combustion chamber for the apogee motor. Around this were arranged two hydrogen peroxide tanks and two nitrogen tanks and the electronics. Nitrogen jets provided attitude and velocity control to align the spin axis, and hydrogen peroxide jets positioned the satellite. Each system had two jets, one parallel and one perpendicular to the spin axis.
Syncom 2
Syncom 2 was launched into a high-altitude, geosynchronous orbit from Cape Canaveral on July 26, 1963. Six hours after launch, the apogee motor was fired to place the spacecraft into an orbit ranging from 34,100 to 36,440 kilometers, with a drift rate of 7.5 degrees per day eastward. The apogee was then raised and the drift rate changed to 4.5 degrees per day westward toward the desired position over 55 degrees longitude. After two weeks of drifting, the nitrogen jets were pulsed in a series of four firings to slow the spacecraft to near-zero drift on August 16, followed by an alignment maneuver. The final orbit was geosynchronous with an inclination of 33 degrees. Operations were turned over to the DOD on January 1, 1965.
Syncom 3
Syncom 3 was inserted into an elliptical orbit inclined 16 degrees to the equator following a third-stage yaw maneuver. The apogee motor was fired to remove most of the remaining inclination and to provide a circular near-synchronous orbit of 35,670 kilometers by 35,908 kilometers. The spacecraft next carried out a series of attitude and velocity maneuvers to align itself with the equator at an inclination of 0.1 degrees and to slow its speed so it drifted west to the planned location at 180 degrees longitude, where its speed at altitude was synchronized with Earth. These maneuvers were completed by September 23, 1964, and Syncom 3 was used in a variety of communications tests, including the transmission of the Olympics, transmissions among the Philippines, USNS Kingsport and Camp Roberts, California, and teletype transmissions to an aircraft on the San Francisco-Honolulu route. Once satellite operations were turned over, the DOD operated it through 1966. It was turned off in April 1969. It is expected to remain in orbit far into the future, possibly for millions of years, NASA said.
Syncom’s Legacy
The Syncom satellites were minuscule compared to today’s geostationary satellites, which run 6 meters long and feature elongated solar panels that stretch the length of a basketball court. But the smaller, older spacecraft left an outsized legacy, demonstrating the overall viability of geostationary communications satellites. They serve as forerunners to today’s powerful Intelsat series, demonstrating the technology and feasibility of geostationary satellites for commercial communications. Intelsat built upon the Syncom designs, adding commercial capacity and improved capabilities.