Fun Facts
Voyager 1 left Earth in 1977 and has never stopped. It is now so far away that a radio command takes almost a full day to reach it, and the answer takes another day to come back.
Earth and Voyager 1 are pulling apart at about 17 km/s.
This strip is to scale, from the Sun out to Voyager 1. Press the button and a ping leaves Earth at the speed of light. It is the same trip every command from NASA's Deep Space Network makes. Your browser remembers when you sent it, so you can come back tomorrow and watch it land.
Pick a date between 1990 and 2100 to see where Voyager 1 was, or will be. The printout comes from a small Fortran 90 program (the kind of language JPL's ground software was written in) ported line for line to JavaScript, so it looks the same as when the program runs in a terminal.
Range is from Earth, so it rises and falls by about 1 AU (around 8 light-minutes) over the year as Earth swings around the Sun.
A picture of Voyager 1 goes around social media every few months claiming it has 69 KB of memory, uses an 8-track tape, and runs on Fortran code written in 1977. Here is how each claim holds up.
About 69 KB is the usual figure for all three of its onboard computer systems combined: commands, attitude control, and data handling. Each one is far smaller. A single phone photo is bigger than everything Voyager 1 can remember.
It had a digital reel-to-reel tape recorder that wrote on 8 tracks, not a car-stereo 8-track cartridge. It held about 536 megabits, roughly 67 MB, and was used to store data until it could be played back to Earth.
As far as public accounts go, the spacecraft's own computers were programmed in assembly-level machine code, written for their custom processors. Fortran ran on the ground, in the software that planned trajectories and built the command loads sent up to the spacecraft. Later ground tools moved to C.
Voyager 1 hasn't fired its engines to change course since its last planet flyby (Saturn, in 1980), so it coasts in a nearly straight line away from the Sun at about 17 km/s, or 3.58 AU per year. It's heading toward the constellation Ophiuchus, about 35° above the plane the planets orbit in.
This simple model stays within roughly half an AU (a few light-minutes) of NASA's tracking for the years shown. NASA itself uses SPICE ephemeris files that are good to within kilometers.