The amazing Voyager space probes

Way back in 1977, NASA launched the Voyager 1 probe into space to do close up studies of Jupiter and Saturn. The mission was to be for five years but Voyager kept going and going, leaving the solar system and in August 2012 became the first human-made object to enter interstellar space, continuing to send back data for nearly half a century.

But in December scientists said that a problem with the onboard computers resulted in the probe sending back gibberish. But rather than give up on the plucky little probe, engineers did a remote fix, even though it was 15 billion miles away.

The recent problem was related to one of the spacecraft’s three onboard computers, which are responsible for packaging the science and engineering data before it is sent to Earth. Unable to repair a broken chip, the JPL team decided to move the corrupted code elsewhere, a tricky job considering the old technology.

The computers on Voyager 1 and its sister probe, Voyager 2, have less than 70 kilobytes of memory in total – the equivalent of a low-resolution computer image. They use old-fashioned digital tape to record data.

The fix was transmitted from Earth on 18 April but it took two days to assess if it had been successful as a radio signal takes about 22 and a half hours to reach Voyager 1 and another 22 and a half hours for a response to come back to Earth. “When the mission flight team heard back from the spacecraft on 20 April, they saw that the modification worked,” JPL said.

The Retired Canadian astronaut Chris Hadfield, who flew two space shuttle missions and acted as commander of the International Space Station, compared the JPL mission to long-distance maintenance on a vintage car.

“Imagine a computer chip fails in your 1977 vehicle. Now imagine it’s in interstellar space, 15bn miles away,” Hadfield wrote on X. “Nasa’s Voyager probe just got fixed by this team of brilliant software mechanics.

Voyager 1 and 2 have made numerous scientific discoveries, including taking detailed recordings of Saturn and revealing that Jupiter also has rings, as well as active volcanism on one of its moons, Io. The probes later discovered 23 new moons around the outer planets.

As their trajectory takes them so far from the sun, the Voyager probes are unable to use solar panels, instead converting the heat produced from the natural radioactive decay of plutonium into electricity to power the spacecraft’s systems.

You have got to hand it to the NASA scientists and engineers, to design something in 1977 that can still function nearly 50 years later, way beyond the initial range of operation. If there ever was a bunch of people who deserved the description of over-achievers, it is them.


  1. Katydid says

    Voyager, the Mars Rovers that lasted far, far beyond their expected lifespan…NASA gives great value for the money. Astounding how much the original programmers were able to do with “1960s technology, with clock speeds measured in KHz and RAM in kbytes, running hand-crafted software, crammed into 4 Kwords of CMOS memory per computer.” And an 8-track tape for data storage.*


  2. Matt G says

    The Star Trek voyages were also supposed to last five years, and they’ve been going on for nearly 60! I wonder what it’s like to work on a project from the seventies when so much else has happened since. I suppose the people involved do other things as well.

  3. kenny256 says

    Just wait till they go back to the moon. Take a fresh battery for the LRV, swap it in and drive off in the first EV, Electric Vehicle, built in 1970.

  4. Robbo says


    from Wikipaedia:

    “In 1888, the German Andreas Flocken designed the Flocken Elektrowagen, regarded by some as the first “real” electric car.”

    they’ve been around for a while! pretty sure the Flocken Elektrowagen didn’t go to the moon though…

  5. file thirteen says

    You have got to hand it to the NASA scientists and engineers, to design something in 1977 that can still function nearly 50 years later, way beyond the initial range of operation. If there ever was a bunch of people who deserved the description of over-achievers, it is them.

    Admirable. The current day scientists and engineers have been guided towards more important priorities. 😣

  6. billseymour says

    This retired computer programmer sits in awe of the accomplishment.

    Back in the late 1970s, still my wires-and-pliers days, I designed and built a prototype for an EKG machine for Allegheny General Hospital in Pittsburgh.  I was able to use an early 16-bit microprocessor, the Texas Instruments TMS9900; and I had 64k of RAM.  I tried to use magnetic bubble memory to store the data, but I couldn’t get it to work, and wound up using a cassette tape instead.  Those were the days.

    That was the job that caused me to change my vocation from electronics technician to programmer.

  7. Silentbob says

    Predates the Commodore 64, has never been serviced, and fixes itself by radio at a range of 15 billion miles.


  8. Silentbob says

    15 billion miles is about 164 AU (astronomical units). For reference Pluto is about 40 AU (Earth by definition is 1 AU) from the Sun.

    On August 25, 2012, Voyager 1 crossed the heliopause. The Sun has particles streaming out of it called the solar wind and there’s a bow shock, like the wake of a ship, where the environment ceases to be dominated by the solar wind, and instead interstellar particles dominate. That boundary is called the heliopause. That’s why both Voyagers can be truly said to be in interstellar space. (Voyager 2 crossed in 2018.)

  9. Dunc says

    For comparison, the content making up this web page totals 444.98 kB, and rendering it is using around 15 MB of memory. And let’s not talk about all the errors and load failure warnings in the console output…

  10. Silentbob says

    The Voyagers relied on a unique alignment of the planets so they could use the gravitational slingshot technique. The laws of physics allow that if a spacecraft approachs a planet at the right trajectory, the gravity of the planet will “fling” the spacecraft away at high velocity. This is how a single probe was able to visit all four major outer planets (Jupiter, Saturn, Uranus, Nepture). It really was a sort of game of celestial billiards. And it worked. Here’s a NASA animation showing how perfect the timing was to pull of the Voyager mission.

  11. steve oberski says

    Back in the dawn of time I worked on a proto-type sub-surface instrument to measure ocean current velocity using the acoustic doppler effect, connected to the land base station by a few kilometers of armoured fibre-optic cable and I was reasonably impressed by my efforts.

    Not so much after reading this.

  12. birgerjohansson says

    Raging Bee @ 5
    Doesn’t matter. Mere ‘facts’ have not mattered since Dubya, and earlier.

    Rob Grigjanis @ 13
    Earlier today I worked out the average velocity is sonething around 17 km/s.
    If it had been launched in the direction of where Alpha Centauri will be, it would have arrived in 50,000 years (when Alpha Centauri will be 3 light years away.)

    Robbo @ 14
    That plot element was soo disappointing. By contrast, The Wrath of Khan was halfway decent, even though they never explained if the sun was pre-existing or created by the Genesis device. Also, nebula clouds are nowhere that thick.

  13. Ridana says

    Given all the electromagnetic radiation in space, how can magnetic tape storage still be functional? Or ever have been useful to begin with? Obviously I don’t understand what they’re writing/storing, or the medium (or anything, really), or am overestimating the radiation type/quantity.

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