The universe holds many mysteries. But as of mid-May, it’s a computer, not a stellar mystery, that NASA is trying to figure out. the probe trip 1, sent in 1977, has an attitude problem. A mid-life crisis for the oldest spacecraft still in operation?
The telemetry data that reaches the American space agency after a journey of more than twenty hours and 23 billion kilometers is falsified. The problem comes from the so-called “AACS” system. “This system controls the position, i.e. the orientation of the probe in spacedescribes Rosine Lallement, astrophysicist at the Paris Observatory. In particular, it ensures that the communication antenna stays well aligned to the earth. » Well, the situational data now reaching Earth is gibberish.
→ READ AGAIN. Voyager 1 has officially left the solar system
“It’s a completely random message that doesn’t make any sense, says Michel Blanc, astrophysicist at the Irap (Research Institute of Astrophysics and Planetology). It’s not even that the data shows the wrong alignment, it’s completely incomprehensible. » However, the system works and the antenna is obviously well aligned, as NASA manages the exchange with the device without hesitation. “If the system were defective, we would have lost the connection”, the researcher remembers.
An interstellar medium that would have broken the device
The probe also did not go into degraded mode and the scientific data also transmitted over the antenna corresponds well to what is expected and predicted by the theory. So where does the problem come from? “Something in the electronics or the software must have taken a hitsays Raisin Lallement. Maybe it’s a reaction to collisions with high-energy particles? »
Since August 2012, trip 1 has actually penetrated farther into the interstellar medium, the region between the stars, than any human object that has been sent into space. The probe has left the heliosphere, the sun’s zone of influence. “Never before has a mission taken so long and never before has a probe traveled in this environment. This inevitably confronts us with a lot of new and unknown things,” Philosopher the specialist of the heliosphere.
The twin device, the probe traveler 2In 2018 she broke through the barrier of the solar cocoon, the heliopause. And so far it doesn’t seem to have any problems. Perhaps it’s simply because its interstellar sojourn was shorter and the device was less subject to particle attacks. Or maybe the part of the universe where traveler 2 Advance behaves differently than that of trip 1the two probes did not go in the same direction.
A possible solution if the “bug” comes from the software
To see more clearly, NASA launched a diagnostic of the software and hardware of trip 1. If the defect is software, it is possible to send a patch. “The on-board software is regularly improved, for example for the format and compression of the data”, commented Michel Blanc. If it is a hardware problem, however, one must hope for redundancy. In 2017, NASA used secondary engines to replace the main engines. “It’s also possible that the team never finds the root cause of the problem and just adjusts,” said Suzanne Dodd, who is responsible for the Voyager program at the American agency.
In any case, the probe should only function for a few more years. Experts estimate that around 2025 it will no longer produce enough energy to continue transmitting. Three plutonium core batteries, RTGs (Radioisotope Thermoelectric Generators), provide its energy. Over time, they deliver less than 250 watts, which is equivalent to some incandescent bulbs. And long after he lost contact with his home planet, in about thirty-eight thousand years, trip 1 will pass “close” to a star in the constellation Ursa Minor. Far, very far from the humanity that painstakingly assembled it.
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