NASA Turns On Backup Radio Not Used Since 1981 To Ping Voyager 1 15 Billion Miles Away
According to a NASA blog post, the transmitter shut-off may have been prompted by Voyager’s fault protection system, which autonomously responds to onboard issues. An example given by the space agency involved if the spacecraft overdraws its power supply, fault protection will conserve power by turning off systems that are not essential for keeping Voyager flying.
NASA reported that on October 16, the flight team sent a command to one of Voyager’s heaters. While the spacecraft should still have plenty of power to operate the heater, the command instead triggered the fault protection system. The team did not learn of the issue until October 18, when the Deep Space Network could not detect Voyager 1’s signal.
On October 19, the spacecraft stopped communicating entirely. The flight team reported it suspected the spacecraft’s fault protection system was triggered two more times, and that it turned off the X-band transmitter, and switched to a second radio transmitter called the S-band. While the S-band consumes less power, it had not been used since 1981, while also transmitting a much fainter signal. The flight team was not sure if the S-band would be able to be detected some 15 billion miles from Earth, but the Deep Space Network was able to locate it.
NASA stated it will leave the S-band on until it is able to determine what triggered the fault protection system. The team is currently working to gather more data that might help them figure out what happened and hopefully return Voyager 1 to normal operations.