Voyager 1 loses contact with NASA and switches on retro transmitter that has not been used since 1981

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An image of the Voyager 1 probe in space. — Credit: NASA/JPL-Caltech

Scientists lost contact with the interstellar Voyager 1 probe from Oct. 19 to 24, after a technical glitch forced the spacecraft’s main radio transmitter to shut down, NASA officials wrote in a blog post. Engineers have since made contact with Voyager 1’s weaker spare transmitter, which has not been used since 1981, while they assess the situation.

“The transmitter shutdown appears to have been caused by the spacecraft’s fault protection system, which responds autonomously to onboard problems,” NASA officials wrote in the blog post. “For example, if the spacecraft overloads its power supply, the fault protection will conserve energy by disabling systems that are not essential to keep the spacecraft flying,” including the spacecraft’s main radio transmitter, the team added.

Once communication is restored, it may take several days or weeks before the underlying problem is identified.

Interstellar IT

Communicating with Voyager 1 and its twin spacecraft, Voyager 2, is not easy. Currently more than 15 billion miles from Earth, Voyager 1 is the farthest man-made object in the universe. Commands sent from Earth take 23 hours to reach the spacecraft beyond Earth at its current position edge of the solar systemand it takes another 23 hours for Voyager 1’s responses to return to Earth.

According to NASA, the current communications outage began on October 16, after engineers sent Voyager 1 a command to turn on one of its heating elements. Although the spacecraft should have had enough power to execute this command, the prompt instead activated Voyager 1’s fault protection system.

Two days later, when NASA engineers searched for Voyager 1’s response with the Deep Space Network – a global network of radio antennas used to support interplanetary missions – they were unable to detect the spacecraft’s signal. The team finally found Voyager 1’s signal later that day. However, the next day (October 19), communications with Voyager appeared to “stop completely,” NASA said.

Engineers suspect that Voyager 1’s fault protection system operated two more times during this period. This forced the spacecraft to turn off its main X-band radio transmitter and switch to its backup S-band transmitter, which uses a different frequency and is “significantly weaker” than the main transmitter, according to NASA.

“Although S-band consumes less power, Voyager 1 has not used it to communicate with Earth since 1981,” the agency added.

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On October 22, engineers sent a command to confirm that the spacecraft was indeed using its spare S-band transmitter. Two days later, the team successfully restored contact with Voyager 1. NASA engineers are now working to diagnose the problem that triggered Voyager 1’s fault protection system and restore it to normal operation.

Voyager 1 and 2 were launched in 1977. They are still the only two spacecraft to have done so go beyond the heliosphere – the bubble of charged solar particles that envelop our solar system – making them humanity’s first (and so far only) interstellar vehicles. As the spacecraft ages and moves further away from Earth, technical problems are becoming more and more common. So far, scientists have managed to solve these interstellar IT problems billions of kilometers away, keeping both Voyager probes functional.