Nasa has detected a “heartbeat” signal from the Voyager 2 spacecraft after the space agency mistakenly cut contact.
Launched in 1977, the probe has been sending back crucial data on planets in the solar system and interstellar space, beyond the Sun's heliosphere.
At the time of communication loss, Voyager 2 was located more than 19.9 billion kilometres from Earth.
Nasa had said that a “series of planned commands … inadvertently caused the antenna to point two degrees away from Earth”, thus Voyager 2 was not able to receive commands.
On Tuesday, Nasa's Deep Space Network picked up a “heartbeat signal”, project manager Suzanne Dodd said. The signal indicates that the spacecraft is still operating.
The latest news “buoyed our spirits”, she said in an email to the Associated Press.
Flight controllers at a laboratory in California will now try to turn the spacecraft's antenna back towards Earth.
The spacecraft is programmed to reset its orientation multiple times each year, so Nasa expects communications to re-establish during the next reboot scheduled for October 15.
“The mission team expects Voyager 2 to remain on its planned trajectory during the quiet period,” the space agency said.
Voyager 2 and other deep-space spacecraft operated by Nasa send and receive data through the Deep Space Network, an array of ground satellites.
The science community has benefitted from Voyager 2's data for decades, as it sent back data on gas giants Jupiter and Saturn and icy planets Uranus and Neptune.
It entered interstellar space in 2018, at a distance of 17.9 billion km, a region in space beyond the influence of the solar system.
It became the second spacecraft in history to enter the space between stars, after Voyager 1, which is still operational.
Both probes were launched to explore Jupiter and Saturn, but their missions were extended after completing their first objectives.
Data from interstellar space is helping scientists to measure the interstellar fields, particles and waves unaffected by the solar wind.
This is not the first time Nasa has lost contact with the interstellar probe.
In 2020, maintenance to the Deep Space Network caused contact with the spacecraft to cut for eight months.
