The AACS controls the orientation of the spacecraft from 45 years old. Among other duties, he keeps Voyager 1’s high-gain antenna pointed precisely at Earth, allowing him to send data home. All signs suggest AACS is still working, but the telemetry data it returns is invalid. For example, the data may appear to be randomly generated or may not reflect any possible state the AACS might be in.
El problema no ha activado ningún sistema de protection contra fallos a bordo, que está designed para poner la nave espacial en “modo seguro”, un estado en el que solo se llevan a cabo las operations esenciales, dando tiempo a los ingenieros para diagnosticar un problem. Voyager 1’s signal also did not weaken, suggesting that the high-gain antenna remains in its prescribed orientation with Earth.
The team will continue to monitor the signal closely while continuing to determine if the invalid data is coming directly from the AACS or from another system involved in producing and sending telemetry data. Until the nature of the problem is better understood, the team cannot predict whether it could affect how long the spacecraft can collect and transmit scientific data.
20 light hours from Earth
Voyager 1 is currently at 23,300 million kilometers from Earth, and it takes 20 hours and 33 minutes for light to travel this difference. That means it takes about two days to send a message to Voyager 1 and get a response, a time frame the mission team is well used to.
“A mystery like this is normal at this point in the Voyager mission,” Suzanne Dodd, project manager for Voyager 1 and 2 at NASA’s Jet Propulsion Laboratory in Southern California, said in a statement.
“The spacecraft are almost 45 years old, which is far beyond what mission planners had anticipated. We are also in the space interstellar, a high radiation environment in which no spacecraft has ever flown before. So there are big challenges for the engineering team. But I think if there is a way to solve this problem with AACS, our team will find it.”
The team might not find the source of the anomaly and adapt to it, Dodd said. If they find the source, they may be able to fix the problem through software modifications or possibly by using one of the spacecraft’s redundant hardware systems.
It wouldn’t be the first time the Voyager team had relied on backup hardware: In 2017, Voyager 1’s main thrusters showed signs of degradation, so engineers switched to another set of thrusters that had were originally used during the planetary encounters of the spacecraft. These thrusters worked, despite having been unused for 37 years.
Voyager 1’s twin, Voyager 2 (currently 12.1 billion miles from Earth), continues to function normally.
The two Voyagers, launched in 1977, have operated much longer than expected by mission planners and are the only spacecraft collecting data in interstellar space. The information they provide about this region has led to a better understanding of the heliosphere, the diffuse barrier that the sun creates around the planets of our solar system.
Each spacecraft produces about 4 watts less electrical power per year, which limits the number of systems the spacecraft can operate. The mission’s engineering team shut down various subsystems and heaters to reserve power for science instruments and critical systems. No science instruments have yet been shut down due to the power drop, and the Voyager team is working to keep both spacecraft operational and make science unique beyond 2025.
As engineers continue to work to solve the mystery Voyager 1 has presented to them, mission scientists will continue to make the most of the data from the spacecraft’s unique perspective.