Engineers use backup transmitter inactive since 1981 to reconnect with Voyager 1

On October 24, NASA's flight team successfully reestablished contact with Voyager 1 after a brief interruption in communications. The spacecraft, now over 24.7 billion kilometers away from Earth and traveling through interstellar space, had ceased transmitting signals on October 19 when its X-band transmitter was turned off. This reconnection was achieved by utilizing a backup S-band transmitter that had not been used since 1981.

The interruption began when communications with Voyager 1 ceased completely on October 19. Antennas around the world had not received any signals, leading engineers to realize there was an issue. On October 16, the team supervising Voyager 1 had sent a command to the spacecraft to turn on one of its heaters. Instead of increasing power, this action triggered the spacecraft's fault protection system, which conserves power by turning off non-essential systems, including the main radio transmitter.

NASA explained that the reason for the recent silence was that one of Voyager 1's two radio transmitters had turned off, "triggered by the activation of the fault protection system in response to a possible drop in power levels." The flight team first realized there was an issue on October 18, when the spacecraft failed to respond to the command sent on October 16, and the Deep Space Network did not detect a signal from Voyager 1.

Faced with the communication blackout, engineers explored options to reconnect with the distant probe. The flight team didn't want to risk sending another signal to the X-band transmitter and triggering the fault protection system again. Instead, on October 22, a command was sent to the S-band transmitter to confirm that Voyager 1 was using its backup transmitter. This transmitter operates at a different frequency and is less powerful than the X-band transmitter; it had not been used to communicate with Earth since 1981.

Despite concerns, engineers were able to detect Voyager 1's signal with the antennas of the Deep Space Network located in Madrid and Canberra. The S-band transmitter, which consumes less energy and transmits a significantly fainter signal, proved to be a viable alternative. NASA officials added: "For example, if the spacecraft overdraws its power supply, fault protection will conserve power by turning off systems that aren't essential for keeping the spacecraft flying," including the craft's main radio transmitter.

With communication restored, the team is now working to diagnose the issue that triggered Voyager 1's fault protection system and to restore it to normal operations. Experts say it could take weeks to discover what activated the protection system, as the team is currently investigating the causes of the failure and evaluating the spacecraft's general state to avoid future interruptions. "Now, the only thing left is to wait to recover normal operations of Voyager 1," one report noted.

This incident adds to a series of interventions that have been necessary to keep the Voyager 1 mission active, as its time in deep space has taken a toll on its instruments and caused an increasing number of technical issues. Earlier in 2023, the team had to fix a separate communications glitch that was causing Voyager 1 to transmit gibberish. One of the failures was a problem with a memory chip. Another failure was the need to reactivate engines that had remained inactive for decades. Reactivating these engines allowed NASA to reorient Voyager 1 toward Earth and preserve communication.

Voyager 1, launched by NASA in 1977, became the first spacecraft to cross the boundary of our solar system, venturing into interstellar space in 2012. It is the most distant human-made object in the universe, now located 23 light-hours away from Earth. Commands sent from Earth take 23 hours to reach the spacecraft at its current position. As the spacecraft ages and moves ever farther from Earth, technical issues are becoming more frequent.

The interruption of communication motivated the flight team to use the alternate S-band transmitter, as they were unsure a signal on the S-band frequency could be detected at such a distance. Despite the lower power, the successful detection of Voyager 1's signal demonstrated the resilience and adaptability of the mission team. NASA engineers are now working to gather information that will help them figure out what happened and return Voyager 1 to normal operations.

While Voyager 1 should have had ample power to operate the heater, the fault protection system's activation indicates potential power supply issues. The team suspects that the protection system may have activated redundantly, turning off the X-band transmitter and switching to the S-band transmitter. As one source humorously remarked, "Please, don't scare us anymore; we've had enough for a while."

This incident highlights the challenges of maintaining communication with a spacecraft operating billions of miles away, relying on technology that has exceeded its expected lifespan. So far, scientists have managed to troubleshoot these interstellar IT problems from Earth, keeping both Voyager probes functional. The mission flight team continues to tackle these challenges, ensuring that Voyager 1 remains operational and continues to send valuable data back to Earth.

With communication restored, it could take several more days or weeks for the underlying issue to be identified. The team is focused on diagnosing and resolving the issues to prevent future interruptions. As Voyager 1 continues its journey through interstellar space, the mission stands as a testament to human ingenuity and the enduring legacy of exploration.

Sources: El Confidencial, Space.com, livescience.com, Mundo Deportivo

This article was written in collaboration with generative AI company Alchemiq