Voyager 2: Communication Reestablished With One Big Shout

You could practically hear the collective “PHEW!” as NASA announced that they had reestablished full two-way communications with Voyager 2 on Friday afternoon! Details are few at this point — hopefully we’ll get more information on how this was pulled off, since we suspect there was some interesting wizardry involved. If you haven’t been following along, here’s a quick recap of the situation.

As we previously reported, a wayward command that was sent to Voyager 2, currently almost 19 light-hours distant from Earth, reoriented the spacecraft by a mere two degrees. It doesn’t sound like much, but the very narrow beamwidth on Voyager‘s high-gain antenna and the vast distance put it out of touch with the Canberra Deep Space Network station, currently the only ground station with line-of-sight to the spacecraft. While this was certainly a problem, NASA controllers seemed to take it in stride thanks to a contingency program which would automatically force the spacecraft to realign itself to point at Earth using its Canopus star tracker. The only catch was, that system wasn’t set to engage until October.

With this latest development, it appears that mission controllers weren’t willing to wait that long. Instead, based on what was universally referred to in the non-tech media as a “heartbeat” from Voyager on August 1– it appears that what they were really talking about was the use of multiple antennas at the Canberra site to pick up a weak carrier signal from the probe — they decided to send an “interstellar shout” and attempt to reorient the antenna. The 70-m DSS-43 dish blasted out the message early in the morning of August 2, and 37 hours later, science and engineering data started streaming into the antenna again, indicating that Voyager 2 was pointing back at Earth and operating fine.

Hats off to everyone involved in making this fix and getting humanity’s most remote outpost back online. If you want to follow the heroics in nearly real-time, or just like watching what goes on at the intersection of Big Engineering and Big Science, make sure you check out the Canberra DSN Twitter feed.

35 thoughts on “Voyager 2: Communication Reestablished With One Big Shout

    1. Sadly none of these heroes were hired by Microsoft, and the world suffers the consequences still. (Or at least those do who use Windows.)

      And it’s been downhill ever since. What passes for firmware in (consumer) devices these days is barely functioning abominations rolled up in some sweatshop in China or India.

  1. I worked on that transmitter. It’s dual band, X- and S-band. Canberra is in the strongest place to contact both Voyagers since they are now located ‘south’ of the plane of the ecliptic. The S-Band transmitter is 80 kW into a 70m dish that adds ‘about’ 67db of gain. They’d planned to be able to ‘talk’ to both Voyagers up to the early 2030s, so… it should be enough for them to ‘hear’ a transmission even if they’re pointed slightly away. I’m glad they were able to restore it’s position.

    Somewhere, there’s a photo of Earth from Voyager 1 – in 1990. We’re just a tiny, tiny dot. And that was 33 years ago. And I think they’ve powered off the cameras for power savings, so that’s all we’ll see for now.

        1. Just kidding of course.
          In case of Voyager, they perhaps sent a short but strong radio “burst”.

          Which contained a sequence with just this one single command that tells Voyager to realign the antenna. A shortened version of what’s usually being sent to Voyager, so to say.

          Shouting could be done by either “pulsing” the transmitter accordingly (think of pulse-width modulation) or by driving it with a strong, but unfiltered square wave signal. That would make sense in sofar, as there’s a strong but short peak, when a transmitter is “switched on”.

          Or maybe it’s done by running the transmitter out-of-specification. Like with a CB radio linear. This can be done by overvolting, for example. Or by feeding the linear with a stronger-than-normal input signal. If the transmission is short enough and/or if the transmitter is cooled properly, this works without damaging the transmitter.

          Or by limiting bandwidth of the radio signal somehow (smaller=same energy, but more concentated within a narrow area). However, this gives a worse signal-noise-ratio, which requires error-correction on the receiver side to work harder.
          Then, polarization is also a factor in radio communications. Here it might be circular? No idea.

          Generally speaking, saving bandwidth can be done by using just one side band, instead of two. And/or by suppressing or lowering the carrier wave. If the receiver can handle different modulation types. That’s what differentiates AM, DSB and SSB, essentially. It’s all a variation of same thing.

          Anyway, this is just a wild guess and very simplified.
          Without knowing about the Voyagers’ transceivers and the transceivers on earth, it’s just pure speculation. 🤷‍♂️
          However, I vaguely remember that the Voyagers had Travelling Wave Tubes (TWTs) on bord.. So that’s a starting point, maybe.

  2. With any luck the shout will attract Starseeds and we might be able to buy the plans for an interstellar drive from the Outsiders following them.

    Or maybe Vulcans will hear the shout.

    Or, well, I basically don’t know of any other possible benevolent aliens out there. :)

  3. A few more details:
    “The Deep Space Network used the highest-power transmitter to send the command (the 100-kw S-band uplink from the Canberra site) and timed it to be sent during the best conditions during the antenna tracking pass in order to maximize possible receipt of the command by the spacecraft,” Voyager project manager Suzanne Dodd told AFP.

  4. Still interested to hear what went wrong with their process that they pointed it wrong.

    Operations does just command the probe willy nilly. You’re not really allowed Oopses. The guardrails, simulations are supposed to be in place to catch the mistakes before they get commanded to remote hardware. So what happened?

    And I’m not interested like a bad manager would be. A boss once said to me “I don’t want to place blame I just want to know who did it!” Yeah right.

    I’m just assuming there’s a cautionary tale there about how smart engineers can make bad mistakes. Leave the names out, that’s not important. Those stories are good for creating better guardrails.

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