NASA announced that the Voyager-1 spacecraft has once again started transmitting information back to Earth. For the past few months, the spacecraft had been experiencing communication issues, sending garbled signals.
Voyager-1 is currently about 15 billion miles away from Earth, making it the farthest human-made spacecraft. With a 46-year history, the probe has been showing signs of aging and various anomalies in recent years.
Last November, a computer malfunction caused Voyager-1 to be unable to transmit readable data back to Earth. The Flight Data System’s telemetry modulation unit was only repeating an unrecognizable code. Engineers have since resolved this issue.
On April 20th, Voyager-1 sent a message back to Earth confirming its status. The mission team received the first batch of coherent data regarding the spacecraft’s engineering system health and status, indicating that it is operating normally and in good condition.
In a statement, NASA mentioned, “The Voyager-1 spacecraft is currently transmitting available data about the status and health of its onboard engineering systems.”
“The next step is to enable the spacecraft to resume transmitting scientific data.”
Currently, Voyager-1 has only sent back health data about its onboard systems, but further work is needed to bring the scientific instruments back online.
Due to the vast distance, it takes 22.5 hours for the radio signals from Voyager-1 to reach Earth.
The recent troubles faced by the aging spacecraft have been attributed to chip damage. This caused the spacecraft’s computer to be unable to access crucial software code used to package and transmit information to Earth.
For a period of time, engineers were unable to receive any data from Voyager-1. However, they knew that the spacecraft was still receiving their commands and operating normally in other aspects.
By relocating the affected program code to different spots in the probe’s computer memory, the issue was resolved.
Linda Spilker, project scientist for the Voyager mission at NASA’s Jet Propulsion Laboratory (JPL), stated in a recent statement last Saturday (April 20th), “Today is a great day for Voyager-1. We have reestablished communication with the spacecraft. We look forward to the return of valuable scientific data.”
Voyager-1 embarked from Earth on September 5th, 1977, a few days after its twin spacecraft, Voyager-2. Their primary mission was to survey Jupiter, Saturn, Uranus, and Neptune, which they completed in 1989.
Subsequently, they were directed towards deep space, roughly aiming towards the center of the Milky Way galaxy.
Their power is derived from Radioisotope Thermoelectric Generators (RTGs), which convert the heat from decaying plutonium into electricity. The ongoing decay process means that the power generated by the RTGs decreases slightly each year.
The exact duration for which the Voyager spacecraft can continue to operate is uncertain, but engineers have consistently found ways to extend their operational life by several years.
In 1990, NASA extended the mission once again, this time aiming to send the spacecraft beyond the Heliopause, the boundary where the solar wind from the Sun encounters the interstellar medium. Voyager-1 reached this boundary in 2012, while Voyager-2, due to its slower speed and different trajectory from its sibling spacecraft, arrived in 2018.
To date, they are the only spacecraft operating beyond the Heliopause, far beyond the orbit of Pluto. The Heliopause is the thin outermost layer of the Sun’s atmosphere, forming a protective magnetic bubble around the solar system.
Over time, both spacecraft have encountered unexpected issues and interruptions, including Voyager-2 losing communication with Earth for seven months in 2020. In August 2023, staff inadvertently pointed the spacecraft antenna in the wrong direction, leading to operational difficulties. Ultimately, the mission team employed a “scream” technique to restore communication with Voyager-2. Currently, the spacecraft is over 13 billion miles away from Earth.
The team estimates it will be a few more weeks until they receive scientific data from Voyager-1, eagerly anticipating the content of these data.
“We never know what surprises the Voyager spacecraft will bring, but I am always amazed as they continue their journey,” stated Suzanne Dodd, project manager for the Voyager mission. “We have encountered many anomalies, and they are becoming more challenging. But so far, we have been fortunate to recover from these issues and the mission continues. Young engineers are joining the Voyager team, contributing their knowledge to ensure the mission progresses.”
Despite both spacecraft traveling at speeds exceeding 9 miles per second, they will not come close to another star for tens of thousands of years.