Voyager 1: technical problem fixed, the probe fully operational

45 years after its launch, the Voyager 1 probe was sending totally incoherent telemetry data to Earth as if they were chosen at random: they did not correspond to any possible configuration of the craft. The failure seemed to come from a small instrument, the AACS: the Attitude and Articulation Control Subsystem, a small block of 20 cm by 40 cm, responsible for controlling the orientation of the vessel and above all for keeping the large antenna of the probe pointed. towards the Earth, so that the contact is not broken.

Misrouting of messages

After several weeks of investigations, the engineers in charge of the probe succeeded in identifying the origin of the failure. The AACS started to do pass telemetry data through an on-board computer known to have stopped working correctly years ago, and the computer has corrupted the information. It was therefore sufficient to order the instrument to resume sending data to the correct computer. On the other hand, the reason why the AACS abruptly chose another computer remains mysterious. He probably received an erroneous command generated by another on-board computer. If so, this would indicate that there is a problem elsewhere on the spacecraft. The team will continue to research this underlying issue, but do not believe it to be a long-term health threat to Voyager 1.

45 years old and still useful

The Voyager 1 and Voyager 2 probes were launched in 1977, and both now sail outside one of the limits of the solar system, beyond the bubble of gas and particles produced by our star. They crossed the heliopause, this dynamic boundary whose distance and composition can undergo variations depending on the activity of the Sun respectively in August 2012 for Voyager 1 and in November 2018 for Voyager 2. They have since been evolving in the interstellar medium , a gas composed of atomic nuclei and particles formed by the explosions of other stars. Voyager 1 is the furthest of the two machines: it is 23.5 billion km from Earth while its sister is 19.5 billion km away. At this distance, it is particularly difficult to communicate with them since the messages take about twenty hours to reach their destination.

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