It’s Alive! NASA Reestablishes Contact With Voyager 1 Thanks to a Transmitter That Was Last Used in 1981

At a distance of 15.4 billion miles from Earth, in interstellar space, the Voyager 1 space probe has once again made NASA sweat. However, this scare turned out to be just that–a scare.

Context. After 47 years of traveling through the solar system, Voyager 1 is the farthest spacecraft from Earth. Recently, it had been unreachable for nearly a week, leading to a troubling period of radio silence that alarmed NASA engineers.

While the space agency handled the situation quietly, data from NASA’s Deep Space Network (DSN) indicated that the Voyager’s team was actively trying to establish contact using antennas in Madrid in Spain, and Canberra in Australia.

Chronology of a demise. On Oct. 16, the Voyager flight team at NASA’s Jet Propulsion Laboratory (JPL) sent a command to Voyager 1 to activate one of its heaters.

Since the spacecraft is 23 light-hours away, the command took almost a day to reach it, meaning a response wasn’t expected until Oct. 18. On that day, NASA discovered that something had gone wrong: The DSN antennas received minimal data, as if the space probe was trying to save power. The following day, on Oct. 19, Voyager 1 completely disappeared after triggering its fail-safe system.

An automatic shut-off. In a recent blog post, NASA explains that the sudden loss of communication with Voyager 1 occurred after the probe turned off one of its two radio transmitters, specifically, the X-band radio transmitter.

NASA suspects that the fault protection system likely triggered the shut-off, although the exact cause is still under investigation. One possibility is that non-essential systems were deactivated to conserve power after the spacecraft exceeded its limited energy supply. If this is confirmed, it would be unexpected because Voyager 1’s radioisotope generator was supposed to have enough plutonium to power the heater.

Using the S-band. Despite the shut-off of the X-band transmitter, Voyager 1 never stopped trying to communicate with Earth. It continued to use the S-band, the probe’s second radio transmitter. It requires less power, but Voyager 1 hadn’t used it for communications since 1981.

Engineers at JPL were initially uncertain whether S-band signals, which operate at a different frequency and are weaker than X-band signals, could be detected at such a great distance. However, on Oct. 24, they successfully located the spacecraft using NASA’s DSN antennas.

Third consecutive rescue. Between Nov. 2023 and May 2024, Voyager 1 stopped sending back scientific data due to a damaged memory chip. Once the problem was identified, NASA engineers successfully relocated the necessary code to other parts of the spacecraft’s limited memory, restoring communications.

More recently, mission controllers had to restart engines that had been dormant for decades in order to steer the spacecraft. The fuel tubes Voyager 1 was using had become clogged due to an aging rubber diaphragm, putting the probe at risk of its antennas losing the ability to point toward Earth.

Voyager 1 refuses to quit. Meanwhile, NASA is equally reluctant to let it go. Thanks to the determination of its engineers, communication with the spacecraft has been reestablished via the S-band, allowing the team to investigate the root cause of the issues.

It may take weeks for the team to determine what triggered the fault protection system. However, NASA is cautious and won’t activate the X-band transmitter until it has gathered all the necessary information about what occurred.

Image | NASA

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