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Voyager 1, one of two space probes launched in 1977 to explore the remote areas of our solar system, is still in operation. It is currently more than 23 billion kilometers from Earth and regularly transmits new data. But recently, the team in charge of the mission noticed an anomaly: the telemetry data from the vessel turned out to be inconsistent.
The Voyager 1 spacecraft was launched on September 5, 1977 and had the main task of exploring the planetary systems Jupiter and Saturn. These 45 years of good and loyal service have made it possible to make tremendous scientific progress; the data from the probe in particular made it possible to observe Jupiter’s rings for the first time, shed light on the function of its famous large red spot and learn more about the structure of Io and Europe.
The exploration machine has also revealed the exact structure of Saturn’s rings, confirming the presence of dark bands (called eger) perpendicular to the rings and reveals the existence of additional rings. In 1980, when it arrived close to Titan, the probe made it possible to determine the composition of this moon’s atmosphere – and several other small moons were also discovered. It may seem incredible that the probe’s instruments are still working after so many years. But it may be that Voyager 1 is showing its first signs of fatigue …
A “normal” problem after a 45-year journey
The probe appears to function normally; in any case, it receives and executes commands sent from Earth and conversely collects and sends data back to the mission team as expected. However, the data related to the articulation and attitude control system (AACS) are atypical. This system is responsible for controlling the orientation of the probe; he must in particular make sure that the communication antenna always points towards the Earth. Although it still seems to work, the telemetry data it returns is inconsistent.
The signal returned by the probe is not attenuated, indicating that the antenna is still pointing in the right direction. The researchers also note that this anomaly did not trigger the protection system that was responsible for switching the machine to “safety mode” at the slightest error. Therefore, to date, the team has no idea about the origin of the problem and does not know if this will affect the life of the device or not.
” Such a mystery is normal at this point in the Voyager mission. said Suzanne Dodd, project manager for Voyager 1 and 2 at Jet Propulsion Laboratory. As the scientist reminds us, the two probes in the Voyager program have far exceeded the originally planned lifespan (10 years!). In addition, since August 2012, the probes have been in interstellar space and therefore face a high level of cosmic radiation.
The source of the anomaly is either the AACS itself or another system involved in producing and transmitting the telemetry data. If the problem is identified, it can be solved by modifying the offensive software or by using rescue hardware. Of course, distance does not facilitate the task: it currently takes 20 hours and 33 minutes for light to travel the more than 23 billion kilometers that separate us from the probe. Researchers must therefore be content with the 41-hour latency period between sending their instructions and receiving the answer …
Three more years of data to utilize
Note that this is not the first time that Voyager 1 has suffered a technical error. In 2014, NASA engineers noticed that the probe’s thrusters – which are used to maintain its orientation via small pulses in a few milliseconds – began to decay. To avoid the crash, in 2017 the team decided to turn on four other thrusters … which had not been used for 37 years! And the operation was a success: the probe finally got a few extra years of life.
Each of the Voyager probes produces about 4 watts less electric power per year, which limits the number of systems the vessel can operate. To save energy, several instruments have already been voluntarily deactivated over the years. Remote sensing instruments such as interferometer, infrared radiometer and UV spectrometer have been taken out of service; the cosmic beam and low energy particle detectors are still active.
Voyager 1 is the first man-made object to explore interstellar space; it moves away from the solar system at a rate of about 3.6 AU per year. Its twin probe has been doing the same since the end of 2018. They are expected to remain in operation until at least 2025, after which they will no longer be able to collect and transmit data due to lack of electricity and fuel. To the ground. Until then, scientists will try to get the most out of the data collected by the two devices.
In about 40,000 years, Voyager 1 will operate within 1.6 light-years of Gliese 445, a star in the constellation Giraffe. At the same time, Voyager 2 will pass about 1.7 light-years from the star Ross 248 and in about 296,000 years (!) It will pass 4.3 light-years from Sirius, the brightest star in the world, sky after the Sun.