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I just finished watching The Farthest, a great documentary about the Voyager spacecraft, launched in 1977 and still operational today.

It got me wondering about those people shown in the documentary sitting at consoles monitoring the two Voyager spacecraft. Are the consoles (or some more-modern version thereof) still staffed? During the intervening 4-plus decades has there always been one or more staff person on duty 24/7, 365? If so, what are they doing? If not, what level of staffing is required to monitor the spacecraft?

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    $\begingroup$ I have scripts here that create various plots using data from JPL Horizons. You can find the current distance to the Voyagers, and make an interactive 3D plot of their trajectories. The IDs of the Voyagers are -31 & -32. For trajectories, I recommend a time span of a decade or two, with a time step of 1 year. I like to include an outer planet in the plot to give a sense of scale. (Saturn ID=6, Uranus ID=7). $\endgroup$
    – PM 2Ring
    May 2 at 9:31
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    $\begingroup$ You need to read nytimes.com/2017/08/03/magazine/…. $\endgroup$
    – Peter - Reinstate Monica
    May 4 at 11:27
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    $\begingroup$ Thank you Peter - a wonderful read! "Over decades, the crew members who have remained have forgone promotions, the lure of nearby Silicon Valley and, more recently, retirement, to stay with the spacecraft." $\endgroup$
    – Stu Smith
    May 4 at 15:31

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Continuously? No, for several reasons.

Most significantly, it just isn't possible. Both Voyagers are now so far away that only the 70-meter antennas of the Deep Space Network can communicate with them. Each DSN site only has one of these antennas, and the two Voyagers are both on the same side of the Earth, so there are times when only one antenna is available for the two of them. That antenna can only point in one direction, so except in the rare case of multiple spacecraft close together, it can only talk to one at a time*.

There also isn't any need. The round-trip signal time for Voyager 1 is around 44 hours; for Voyager 2, it's 36 hours. Both spacecraft are pretty much in the middle of nowhere, doing nothing but recording data and periodically forwarding it to Earth. There's no expectation of anything surprising happening, so losing a few hours of data if something goes wrong is no big deal.

Both spacecraft are routinely monitored, but this takes the form of periodic, scheduled communication sessions rather than continuous monitoring.

*Right now, antenna 25 at Goldstone is talking to Mars Odyssey, MAVEN, and the Trace Gas Orbiter, all in orbit around Mars.

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    $\begingroup$ It would still be good to mention that both Voyagers are routinely monitored, and that just because the round trip light time is longer than a day, that doesn't mean that there couldn't be messages sent every day and received every day. After all, DSN is not necessarily having an in-depth conversation with them. They can just "check in" with each other assynchronously. $\endgroup$
    – uhoh
    May 2 at 9:29
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    $\begingroup$ I don't have time to do it right now, but for anyone interested, one can query DSN to see how often they talk to the Voyagers Understanding the information contained in the Deep Space Network XML data? and Power and frequency units used in Deep Space Network XML data? $\endgroup$
    – uhoh
    May 2 at 10:46
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    $\begingroup$ in case anyone reading hasn't seen it before, this page (DSN Now) shows what NASA's massive antennas are currently doing. As I write this it actually shows two of the smaller antennas (DSS 34 and 35) at Canberra receiving data from Voyager 2. I guess maybe they use some form of synthetic aperture or whatever. $\endgroup$
    – user253751
    May 2 at 20:45
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    $\begingroup$ @user253751, with the end of the Pioneer and Galileo programs, the Voyagers are the only spacecraft that need the big antennas. I know that DSN has been experimenting with using antenna groups in place of a single big antenna; I don't know if it's reached the point where they can decommission the 70-meter dishes. $\endgroup$
    – Mark
    May 2 at 21:41
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    $\begingroup$ @Mark see Tradeoffs between using two 34 m and one 70 m Deep Space Network dish? and Why does DSN sometimes uses two dishes at the same time to receive Voyager-1? and links therein. $\endgroup$
    – uhoh
    May 3 at 1:45
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The Voyagers are not monitored continuously.

On average, there is a communications session with each spacecraft every day. For up to 8 hours at a time, science and operations data is received and the occasional command is sent. This is handled by the Deep Space Network operations personnel. Those sessions are planned using visibility data (Voyager 2 is out of reach of the Goldstone and Madrid complexes, so its comms sessions have to be when Voyager 2 is visible from Canberra) and have to fit in the other uses of the DSN (all other interplanetary missions).

They forward the data to the Voyager team, which analyzes it, plans upcoming operations, and prepares new command uploads. I suspect they do this during normal work hours instead of looking at the data as it comes in: there's no benefit in looking at the data immediately when it takes 18 hours to send a command anyway.

From a recent interview:

“The Voyager science isn’t something you need to monitor constantly,” Calla Cofield, a JPL spokesperson, told WIRED via email. “They’re studying this region of space over long distances, so a gap of a few weeks won’t hurt those studies.”

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