NASA Sent An Important Software Patch 12 Billion Miles To Its 1977 Voyager Probes

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The furthest human spacecraft from earth—Voyager 1 and 2—are still getting software updates more than 12 billion miles away, which should help keep the probes operational for many years to come. Smartphone companies can learn a thing or two here.

It all started in 2022 when Voyager 1 began sending garbled data back to Earth. Craft functions were not affected, but the attitude articulation and control system (AACS) was erroneously misdirecting commands from mission control into computer memory rather than carrying them out.

Jet Propulsion Laboratory (JPL) engineers couldn't determine the cause, but were able to confirm that the AACS had switched to an incorrect mode. To stop that from happening again, the agency dispatched a software fix. Suzanne Dodd, JPL's Voyager project manager commented in a media release, “This patch is like an insurance policy that will protect us in the future and help us keep these probes going as long as possible." She added that “these are the only spacecraft to ever operate in interstellar space, so the data they’re sending back is uniquely valuable to our understanding of our local universe.”

voyager trajectories

Sending a patch in this case has obvious challenges. Voyager 2 is receiving the fix first (as a testbed for Voyager 1, which NASA sees as more operationally more important), so at its current distance of 12 billion miles from Earth, the data transmission takes over 18 hours to get to the craft. Beside the communication lag time and age of the probe—45 years young—the risk of data corruption or unplanned effects on Voyager 2 needed to be minimized. Therefore, agency engineers have combed through the code through its writing and review processes. 

After uploading the patch, the team inspected the AACS readings to ensure that it's operating in the correct mode on October 20. We won't know until Oct. 28 for the engineers to greenlight the AACS for operation and issue their first command to the system.