The oldest U.S. government computer still in operation isn’t in some dusty archive or a Cold War bunker, it’s more than 25 billion kilometers (15.5 billion miles) from Earth, riding aboard NASA’s Voyager spacecraft. Despite being launched in 1977 and using technology older than the floppy disk, these computers continue to function, proving that reliability sometimes trumps speed.
While consumer tech chases the newest processors and graphics cards, government systems often hold onto legacy hardware for decades. The U.S. military only recently stopped using floppy disks for nuclear launch systems, and air traffic control still relies on Windows 95 and paper printouts. But Voyager’s systems predate even those making them a unique testament to engineering durability.
Each Voyager probe carries six computers: two Computer Command Systems (18-bit), two Flight Data Systems (16-bit), and two Attitude and Articulation Control Systems (18-bit), all built by General Electric for NASA’s Jet Propulsion Laboratory. They run at just 250 kHz, a fraction of the speed of even a 2013 smartphone and store data on an 8-track digital tape recorder with only 68 kilobytes of capacity.
To send back planetary images and scientific readings from deep space, NASA overwrites old data as soon as it’s transmitted to Earth. During planetary encounters, the system adjusts downlink rates from 19.2 kbps to 115.2 kbps depending on the distance and available power.
In 2022, Voyager 1 suffered a software glitch that caused it to send back garbled data. Unable to repair the hardware, engineers rewrote the affected code and split it across different parts of the FDS memory, carefully updating references so the program would still function. After a 22.5-hour signal delay each way, the fix worked and the spacecraft resumed sending science data.
NASA expects Voyager to keep operating until the 2030s, shutting down instruments gradually to conserve power. After that, these spacecraft and their nearly 50-year-old computers will drift silently through interstellar space, carrying humanity’s most enduring hardware far beyond the Solar System.