Since last November, NASA’s iconic Voyager 1 probe has been sending unreadable science and engineering data to Earth. Now the engineers have confirmed that a small portion of corrupted memory in the flight data subsystem (FDS)—the computer responsible for packaging Voyager’s science and engineering data before the telemetry modulation unit (TMU) and radio transmitter send the data—is the cause:
“In early March, the team issued a ‘poke’ command to prompt the spacecraft to send back a readout of the FDS memory, which includes the computer’s software code as well as variables (values used in the code that can change based on commands or the spacecraft’s status). Using the readout, the team has confirmed that about 3% of the FDS memory has been corrupted, preventing the computer from carrying out normal operations.”
The suspected culprit is a single chip that isn’t working. The chip is responsible for storing part of the affected portion of the FDS memory.
NASA says there are two possible causes of the issue: a hit by an energetic particle from space or simply the age of 46-year-old silicon.
Debugging and fixing a spacecraft is not an easy task. Voyager 1 is the first human-made object to enter interstellar space, the region outside the heliopause, or the bubble of energetic particles and magnetic fields from the Sun. It takes a combined 45 hours from sending a command to the spacecraft to receiving an answer on Earth.
Therefore, it may take weeks or months until engineers find a way for the FDS to operate normally without the unusable memory hardware, so the spacecraft can once again send usable science and engineering data.
Despite that, NASA is optimistic that Voyager 1 will be back at work, eventually. The probe was launched in 1977 and flew by Saturn and Jupiter. Its twin, Voyager 2, is in interstellar space too, operating normally and communicating with NASA over the Deep Space Network.
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