Voyager 1 managed to contact Earth after five months of sending absurd messages

In 2012, Voyager 1 became the first probe to reach unknown interstellar space, crossing the outer boundary of the heliosphere (solar plasma bubble) approximately 18 billion kilometers from the Sun. Its satellite, Voyager 2, will follow it for six years. Later.

After a surprisingly long service life, Voyager 1 stopped sending readable science and engineering data to Earth on November 14, 2023, although mission controllers confirmed that the spacecraft was still receiving commands and operating normally. In March, Voyager’s engineering team at NASA’s Jet Propulsion Laboratory (JPL) in Southern California confirmed that the problem was with one of three onboard computers called the flight data subsystem (FDS). The FDS is responsible for packaging scientific and engineering data before sending it back to Earth.

The fault lies in one chip.

As JPL explained, the team discovered that one chip responsible for storing part of the FDS memory, including part of the FDS computer program code, was not working. The loss of this code rendered scientific and engineering data unusable. Unable to repair the chip, the team decided to place the corrupted code elsewhere in the FDS memory. But no single space is large enough to hold an entire section of code.

So they came up with a plan to split the affected code into sections and store those sections in different places in the FDS. For this plan to work, they also needed to adjust these sections of code to, for example, ensure that they all continued to work as a single unit. Any references to the location of this code elsewhere in FDS memory also needed to be updated.

The team began by selecting the code responsible for packaging the spacecraft’s engineering data. He was sent to a new place in the memory of the FSB on April 18. It takes a radio signal about 22 and a half hours to reach Voyager 1, which is more than 15 billion miles from Earth, and another 22 and a half hours to return. When the mission’s flight team received a response from the spacecraft on April 20, they saw that the modification was working: for the first time in five months, they were able to check the serviceability and condition of the spacecraft.

The success of the repair represents the first step towards extending the life of the ship, which was already considered to be at its last. With a memory hundreds of thousands of times smaller than a smartphone and a radio transmitter that emits as many watts as a refrigerator light bulb, Voyager 1 and Voyager 2 are marvels of endurance. For four decades, they have provided science with valuable data, including images of Jupiter, Saturn, Uranus and Neptune, and the discovery of 22 active moons and volcanoes. Let’s hope that perhaps they will continue to do science for much longer.