One of the Oldest Computers Still Working 25 Billion Kilometers Away

23 Sep One of the Oldest Computers Still Working 25 Billion Kilometers Away

While we remain obsessed with having the latest technology in the palm of our hand, a 48-year-old computer is still working perfectly… thousands of kilometers away from Earth. Built in 1977, NASA’s Voyager probes have survived nearly five decades of temperatures that would destroy any modern smartphone, high doses of radiation, and zero maintenance.

Located 25 billion kilometers from Earth, these computers are the oldest operational government systems in the world, yet they continue sending signals as efficiently as on day one. Voyager 1 and Voyager 2 each house six computers: three different types with two backup units each. These are an 18-bit Command Computer System, a 16-bit Flight Data System, and an 18-bit Attitude and Articulation Control System.

Both were built by General Electric under NASA’s guidance. Obviously, by today’s standards, they are far from fast, and the signals take 23 hours to reach Earth. The main clock runs at 4 MHz, and the CPU operates at just 250 kHz. A single instruction takes 80 microseconds, yielding roughly 8,000 instructions per second. By comparison, a 2013 smartphone ran at 1.5 GHz across four processors, delivering more than 14 billion instructions per second.

If the speed seems laughable, storage capacity is even more so. The probes can store about 68 kilobytes on their 8-track digital tape recorder—less than a single JPEG photo on a smartphone. Yet, surprisingly, even without physical maintenance, software updates have occurred.

When Voyager 1 began sending garbled data, NASA scientists realized part of the Flight Data System software was damaged. After a software update—and a 22-hour wait to send instructions to the probe—the team was able to communicate with it again.

The high redundancy in both hardware and software, combined with the quality of construction from the 1970s, has created practically indestructible machines.