Sending a command to Voyager 1 feels more like mailing a letter than making a phone call. Launched in September 1977, this incredible probe is now about 16 billion miles from Earth, traveling away from the Sun at around 38,000 miles per hour. By November 2026, it will achieve a significant milestone—becoming the first human-made object to be one light-day away from Earth. This means that commands sent will take a full 24 hours to reach Voyager and the same for the response to come back.
Here’s an interesting note from Suzy Dodd, the project manager at NASA’s Jet Propulsion Laboratory (JPL). She mentioned that if she sends a message at 8 a.m. on a Monday, the reply won’t arrive until Wednesday at about the same time. This large communication gap has posed challenges, especially after a significant issue arose in November 2023 when Voyager 1 stopped sending back useful data. The team at JPL spent five months troubleshooting the problem, eventually discovering that a single faulty memory chip was the culprit.
Unfortunately, there was no way to repair this chip. Instead, the team had to find a workaround by dividing the affected software into smaller parts to store in different memory areas. Fixing this issue is no quick task. Linda Spilker, the Voyager 1 project scientist at JPL, explained that it takes roughly 22.5 hours to send a signal to Voyager and another 22.5 hours to receive a reply. They had to prepare commands, send them off, and then wait days for feedback to know if the fix worked.
The solution was sent to the spacecraft on April 18, 2024. After a long wait, they received confirmation two days later that the fix was successful.
This transition also highlights a crucial point: communication will become increasingly slow. As we approach the two-day mark for command responses, updates will be delayed even more, slowing down the ability to address any future issues. Currently, Voyager 1 sends data back at about 160 bits per second. It can usually manage problems autonomously, entering a safe state until communication is possible again.
Voyager 2, which is on a different path, won’t reach that one-light-day mark until 2035. By then, it’s likely that both probes will have stopped transmitting data. They are slowly shutting down instruments to conserve power. Right now, Voyager 1 has two active science instruments, while Voyager 2 has three still functioning.
At JPL, the team’s focus is on patience and careful monitoring. Dodd refers to the spacecraft as “ambassadors” for Earth. Once the round-trip communication escalates to two full days, this term could take on a more literal meaning, with Voyagers sending back infrequent updates while largely operating on their own.
These missions remind us of humanity’s quest for knowledge. In a world where immediate answers are commonplace, Voyagers show that some discoveries take time—often a lot of it. Their journeys continue to inspire discussions about exploration and our place in the universe.
For more about Voyager’s current status, you can check NASA’s latest update.
