Old Spacecraft Sends Radio Messages Back To Earth

An aging spacecraft, that NASA has long forgotten, has suddenly came alive and is communicating back to Earth. The 47-year-old Voyager 1 spacecraft, which is now billions of miles away in interstellar space, encountered technical issues that caused a days-long communications blackout with the historic mission.

The spacecraft is now using a radio transmitter it hasn’t relied on since 1981 to stay in contact with its team on Earth while engineers work to understand what went wrong.

As the spacecraft, launched in September 1977, ages, the team has slowly turned off components to conserve power, allowing Voyager 1 to send back unique science data from 15 billion miles (24 billion kilometers) away.

The probe is the farthest spacecraft from Earth, operating beyond the heliosphere — the sun’s bubble of magnetic fields and particles that extends well beyond Pluto’s orbit — where its instruments directly sample interstellar space.

The new issue is one of several the aging vehicle has faced in recent months, but Voyager’s team keeps finding creative solutions so the storied explorer can zoom along on its cosmic journey through uncharted territory.

Occasionally, engineers send commands to Voyager 1 to turn on some of its heaters and warm components that have sustained radiation damage over the decades, said Bruce Waggoner, the Voyager mission assurance manager. The heat can help reverse the radiation damage, which degrades the performance of the spacecraft’s components, he said.

Messages are relayed to Voyager from mission control at NASA’s Jet Propulsion Laboratory in Pasadena, California, through the agency’s Deep Space Network. The system of radio antennas on Earth helps the agency communicate with Voyager 1 and its twin probe, Voyager 2, as well as other spacecraft exploring our solar system.

Voyager 1 then sends back engineering data to show how it is responding to the commands. It takes about 23 hours for a message to travel one way.

But when a command to the heater was sent on October 16, something triggered the spacecraft’s autonomous fault protection system. If the spacecraft draws more power than it should, the fault protection system automatically shuts off systems that aren’t essential to conserve power.

The team discovered the latest issue when it couldn’t detect the spacecraft’s response signal through the Deep Space Network on 18 October 2024.

Voyager 1 has been using one of its two radio transmitters, called an X-band based on the frequency it utilizes, for decades. Meanwhile, the other transmitter, called the S-band, which uses a different frequency, hasn’t been employed since 1981 because its signal is much fainter than the X-band’s.

Engineers suspect the fault protection system lowered the rate at which data was being sent back from the transmitter, which changed the nature of the signal shared by Voyager 1 to the Deep Space Network monitors. The Voyager 1 team ultimately located the probe’s response later on October 18 by sifting through signals the Deep Space Network was receiving.