February 2026 Update On The Voyager Interstellar Mission
The two Voyager spacecraft were launched in 1977 on a five-year mission to study the gas giants Jupiter and Saturn. What they did after that made them the most successful spacecraft ever
Flushed by the success of the Pioneer 10 and 11 missions to image Jupiter and Saturn in the early 1970s, NASA decided to send two much-improved probes back to obtain more detailed photographs and, using a rare planetary alignment that occurs every 175 years, to continue on to Uranus and Neptune, the mission being dubbed the ‘Grand Tour‘.
Voyager 1 subsequently became the first probe to provide detailed images of Jupiter’s and Saturn’s moons.
After the twin flyby’s were completed, NASA commanded Voyager 1 to make a close pass of Saturn’s moon Titan, which was known to have a substantial atmosphere. This maneuver effectively sent it below the plane of the planets and no further planetary encounters were possible.
Voyager 2’s trajectory allowed it to continue along the plane, for its encounters with Uranus and Neptune, though with a design life of five years, some doubted it would still be operational by then.
The Voyager Extended Mission
After seeing Voyager 2 was in such good condition, NASA decided to keep it operational for the Uranus and Neptune encounters, which occurred in 1986 and 1989 respectively.
On Uranus’ moon Triton, multiple geysers of dark material were seen erupting five miles straight up into the atmosphere, before suddenly drifting 90 miles downwind, revealing Triton is geologically active despite its extreme cold.
On Valentine’s Day 1990, Voyager 1 was by chance in the ideal place to take what has been dubbed the ‘Family Portrait‘ from a distance of 3.7 billion miles, or 40.5 AU, which shows the entire solar system, with the exception of Mercury and Mars, which were obscured by the Sun’s glare, and Pluto, which was too far along it’s orbit to be visible.
Image: NASA
This was the last time the cameras on either spacecraft were used.
The Voyager Interstellar Mission
With the Radioisotope Thermoelectric Generators degrading much slower than expected, it was decided to keep both spacecraft operational as long as possible, to see if they could find the Heliopause, an expexted discontinuity where the Sun’s influence ended, and interstellar space began, and there was great debate on whether they would be able to detect it.
Both Voyagers recorded a steadily decreasing solar wind, which eventually ceased altogether, then reversed in direction. Voyager 1 passed through a ‘turbulent’ region before entering true interstellar space in August 2012, at a distance of 121 Astronomical Units, or 1.1 billion miles.
Voyager 2 passed through the heliopause in November 2018, at a distance of 119 AU. This puts the outer extent of our solar system at around four times the Sun-Pluto distance.
Onboard Instruments
When launched, both Voyagers had identical suites of ten science instruments. After their final planetary encounters and the start of the interstellar phase of their missions, most instruments were switched off as they would not be used again, and this helped to conserve the RTG power supplies.
As of the time of writing, Voyager 1 has four active instruments; Magnetometer, Low-Energy Charged Particle Subsystem, Plasma Wave Subsystem, and Cosmic Ray Subsystem.
Voyager 2 currently has three instruments operating; Magetometer, Plasma Wave Subsystem, and Cosmic Ray Subsystem.
Voyager 1 suddenly stopped sending usable data on November 14, 2023. Over the next few months, NASA tried repeatedly to regain contact, while at the same time trying to determine where the problem lay, raising fears we had lost contact permanently.
They eventually determined a failed chip in the Flight Data Subsystem was the source of the loss of communication, and they were able to ‘remap’ the 1970s software to bypass the broken chip, restoring communication by April 2024.
Both Voyagers are still sending back engineering data about the health of their systems, and data about their interstellar surroundings daily, and are expected, barring some major malfunction, to be able to operate their transmitters until around 2030, by which time they will be no less than 53 years old.
That they have survived for 48 years in that most harsh of evironments is a tribute to how well they were designed and built.
Their ultimate fate
Voyager 1 is currently almost 16 billion miles away, or 171 Astronomical Units, travelling at 38,000 mph.
Voyager 2 is just over 13 billion miles away, or 142 AU, travelling at 35,000 mph.
Sometime around 2035, NASA will probably command them to power down, and they will coast forever, silently travelling the universe.
Voyager 1 is expected to reach the theorized Oort cloud in about 300 years and take about 30,000 years to pass through it. Though it is not heading towards any particular star, in about 40,000 years, it will pass within 1.6 light-years of the star Gliese 445 in the constellation Camelopardalis, 17 light-years away.
Voyager 2 will be the first to pass relatively close to another star; the binary Sirius, the Dog Star so revered by the ancient Egyptians, in the year 296,036.
We can only imagine what wonders they will encounter.
If they are ever discovered by an alien race at least as advanced as us, they should be able to work out from their trajectories their point of origin, and know that at some point in the distant past, another technological race did exist.
Extending that position about as far as it will go, maybe one will be found by a civilisation of intelligent machines, and if they were so inclined, we could perhaps see it returned like Vejur in Star Trek The Motion Picture.
Learn all that is learnable. Return that information to the creator.
But for now, their journeys have barely begun.
About the author: Andy Rowlands is a British university graduate in space science and Principia Scientific International researcher, writer and editor who co-edited the 2019 climate science book ‘The Sky Dragon Slayers: Victory Lap‘