Experts 'predict' time frame of reply from NASA’s Voyager space probe

NASA's Voyager 1 and 2 probes have been in space for more than 45 years, collecting data about the great unknown.

The Voyagers were sent initially to study the outer planets including Jupiter, Saturn, Uranus and Neptune, but then they just kept on going.

In 2019, Nasa’s Voyager 2 reported back with its initial cosmic findings – a year after becoming the second man-made object to 'leave' the Solar System.

NASA/JPL-Caltech

Originally launched in 1977, the Voyager spacecraft and what NASA refers to as 'its twin, Voyager 2', are the "two longest-operating spacecraft in history", NASA says.

The Voyager 2 probe blasted off from Earth in August 1977 - 16 days before its twin spacecraft, Voyager 1 – and crossed the outer edge of the Sun’s protective bubble, known as the heliopause, on November 5 2018.

It entered the interstellar medium – which is the region outside the heliopause made up of gas, dust and cosmic rays – six years after Voyager 1 due to its slower trajectory.

As the Voyager travels through 'interstellar space', it has been sending back data. But the probe also transmits signals, and in deeper space, there's still the question of if they'd be picked up by another system capable of supporting life.

Well, a study from earlier in 2023 looked into how far certain probes have reached and their conclusion is that the earliest a reply would come our way is 2029, IFLScience reports.

The study from the Publications of the Astronomical Society of the Pacific, also considered the Pioneer 10, Pioneer 11, and New Horizons spacecrafts.

The study said: "These spacecraft have communicated with the Deep Station Network (DSN) radio antennas in order to download scientific data and telemetry data. Outward transmissions from DSN travel to the spacecraft and beyond into interstellar space.

It went on: "These transmissions have encountered and will encounter other stars, introducing the possibility that intelligent life in other solar systems will encounter our terrestrial transmissions."

NASA/JPL-Caltech

Explaining their methodology, the study said: "We use the beamwidth of the transmissions between DSN and interstellar spacecraft to perform a search around the past and future positions of each spacecraft obtained from the JPL Horizons System.

"By performing this search over the Gaia Catalogue of Nearby Stars, a catalog of precisely mapped stars within 100 pc, we determine which stars the transmissions of these spacecraft will encounter".

"We highlight stars that are in the background of DSN transmissions and calculate the dates of these encounters to determine the time and place for potential intelligent extraterrestrial life to encounter terrestrial transmissions".

According to IFLScience, Voyager 1 transmissions won't reach their first star until 2044, but they say it will go on to contact some 277 stars by 2341. But so far, they say, Voyager 2 has had success and reached an M-dwarf and brown dwarf, as far back as 2007, but they report a reply wouldn't come until 2033.

One of the papers co-authors, Howard Isaacson, told Popular Science: “This is a famous idea from Carl Sagan, who used it as a plot theme in the movie Contact."

American astronomer Sagan, who died in 1996, wrote a book called Contact, which was used as the basis for the 1997 film which starred Jodie Foster as a scientist who makes contact with extraterrestrial life.

In the film, a broadcast of the 1936 Olympic Games is sent into space and Foster's character and her team discover the video in a signal which has been transmitted back to Earth by someone or something.

Astronomer Jean-Luc Margot has his doubts though, telling Popular Science in April: "Our puny and infrequent transmissions are unlikely to yield a detection of humanity by extraterrestrials.

“The probability that another civilization resides in this tiny bubble is extraordinarily small unless there are millions of civilizations in the Milky Way."