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Voyager and the Deep Space Network Upgrade

The fault protection routines programmed into Voyager 1 and 2 were designed to protect the spacecraft in the event of unforeseen circumstances. Such an event occurred in late January, when a rotation maneuver planned to calibrate Voyager 2’s onboard magnetic field instrument failed to occur because an unexpected delay in its execution left two systems consuming high levels of power (in Voyager terms) at the same time, overdrawing the available power supply.

We looked at this event not long after it happened, and noted that within a couple of days, the Voyager team was able to turn off one of the systems and turn the science instruments back on. Normal operations aboard Voyager 2 were announced on March 3, with five operating science instruments that had been turned off once again returning their data. Such autonomous operation is reassuring because Voyager 2 is now going to lose the ability to receive commands from Earth, owing to upgrades to the Deep Space Network in Australia. This is a temporary situation but one that will last the entire 11 months of the upgrade period.

Fortunately, scientists will still be able to receive science data from the craft, which is now 17 billion kilometers from Earth, but they will not be able to send commands to it during this period. The Canberra site is critical to the Voyager interstellar mission because its 70-meter wide antenna is the only one of the three DSN antennae that can communicate with Voyager 2, which is moving relative to the Earth’s orbital plane in such a way that it can only be seen from the southern hemisphere. Thus the California (Goldstone) and Spain (Robledo de Chavela) sites are ruled out, and there is no southern hemisphere antenna other than Canberra’s DSS43 capable of sending S-band signals powerful enough to communicate with Voyager 2.

Image: DSS43 is a 70-meter-wide (230-feet-wide) radio antenna at the Deep Space Network’s Canberra facility in Australia. It is the only antenna that can send commands to the Voyager 2 spacecraft. Credit: NASA/Canberra Deep Space Communication Complex.

The maintenance at DSS43 is essential, because we have communication and navigation needs for missions like the Mars 2020 rover and future exploration plans for both the Moon and Mars including at some point the crewed missions to the Moon in the Artemis program. Canberra has, in addition to the 70-meter dish, three 34-meter antennae that can receive the Voyager 2 signal, but are unable to transmit commands. During the period in question, Voyager 2 will continue to return data, according to Voyager project manager Suzanne Dodd:

“We put the spacecraft back into a state where it will be just fine, assuming that everything goes normally with it during the time that the antenna is down. If things don’t go normally – which is always a possibility, especially with an aging spacecraft – then the onboard fault protection that’s there can handle the situation.”

Expect the work at Canberra to be completed by January of 2021, placing an updated and more reliable antenna back into service and, presumably, continuing the active work managing Voyager 2’s ongoing mission. Better this, engineers reason, than dealing with future unplanned outages as DSS43 ages, while the upgrades will add state-of-the-art technology to the site. Putting all this in perspective is the fact that the dish has been in service for fully 48 years.

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{ 14 comments… add one }
  • ljk March 5, 2020, 15:47

    Voyager 2 is gathering science data again after recovering from a glitch in interstellar space

    By Meghan Bartels a day ago

    All five remaining instruments on NASA’s venerable Voyager 2 spacecraft are back to gathering science data after power overuse in late January interrupted the probe’s operations.

    NASA made the announcement yesterday (March 3), over a month after the incident occurred. Troubleshooting for the spacecraft is a slow process because of its distance from Earth; it takes 17 hours for each command to reach the probe and for data indicating its efficacy to reach engineers.

    Full article here:

    https://www.space.com/voyager-2-gathering-data-after-glitch.html

  • ljk March 5, 2020, 15:57

    The New York Times tries to shock and frighten with its title:

    When Voyager 2 Calls Home, Earth Soon Won’t Be Able to Answer

    NASA will spend 11 months upgrading the only piece of its Deep Space Network that can send commands to the probe, which has crossed into interstellar space.

    https://www.nytimes.com/2020/03/04/science/voyager-2-nasa-deep-space-network.html

    To quote:

    Being able to only listen could prompt some anxiety. While Voyager 2 will keep collecting and sending back science data, should something go wrong, members of the team will be powerless to help it, and will just have to watch with their hands tied.

    “We’ve been planning on this for over a year,” Ms. Dodd said. “I think like any good planning, we’re prepared for it. And we’ve done our best, you know, we’ve done the best that we can.”

    And the operations to restore Voyager 2 during its recent troubles may highlight how much more life it could have in deepest space, Ms. Dodd said. Never before had all of the spacecraft’s instruments been shut off in this manner. Much to the mission managers’ delight and surprise, they were all brought back to life.

    “They also came back on, which is actually pretty remarkable,” she said.

  • ljk March 5, 2020, 16:01
  • Alexander Tolley March 6, 2020, 11:47

    The Voyager probes continue to attract our attention primarily because they are mankind’s farthest emissaries in space. They are also slowly dying and will within a decade or so run out of power to do anything, just flotsam on shores of interstellar space.

    Sometime this century, I would hope that fast spacecraft will become the new farthest emissaries, paddling deeper into the shallows of interstellar space that ever before.

    • Ashley Baldwin March 6, 2020, 13:42

      Saganesque

  • Another David March 6, 2020, 15:26

    I wonder why NASA did not buy time on the Parkes 64-M telescope for this. The Parkes telescope has been used in the past for the Voyagers. True while I don’t think Parkes was used for transmitting signals, I think it could be done. Maybe the Break Through listening program is taking too much time to allow this.

    Something like 5 to 10 percent of the observing time for the DSS 43 antenna is used for general radio astronomy. An upgrade would be very welcomed, not just for the better signal sensitivity, but even more so if there is an increase in frequency coverage for that probably would means it could more often be combined with the other Southern Hemisphere radio antennas which make up the Australian Long Baseline Array.

    • Paul Gilster March 6, 2020, 16:45

      My understanding is that the Canberra big dish is the only one that can transmit a signal of the needed strength. If anyone has any figures on that, they would be appreciated.

      • James Jason Wentworth March 11, 2020, 6:45

        Could Arecibo–if an emergency developed–also transmit commands to the Voyagers? (Additional equipment [and software] might need to be installed for that to be do-able; Arecibo can listen [as–I *think*–it did to Pioneer 10 and 11], but it may not have a “stock” transmitter capable of sending properly-coded commands.) ALSO, Paul:

        Your idea (in your article, “Voyager to a Star?” [see: https://www.centauri-dreams.org/2015/04/21/voyager-to-a-star/ ]) about the spacecraft each making one last, “empty-the-tank” burn in order to pass within one light-year of two selected stars could also be combined with a Voyager life-extension plan:

        Since the Voyagers were designed to be spin-stabilized during launch (during the final stage burn, because their Titan IIIE launch vehicles were, like Pioneer 10’s & 11’s Atlas-Centaur boosters, each topped by a spin-stabilized TE-M-364-4 [STAR-37E] solid propellant final kick stage, see: http://www.google.com/search?q=Voyager+spacecraft+launch+configuration&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiLu5uDmYLiAhWIJjQIHQlXAuMQ_AUIECgD&biw=1440&bih=789 [the two West German/NASA Helios close-approach solar probes also used Titan IIIE-STAR-37E launch vehicles]), the Voyager spacecraft should spin smoothly about their front-to-back centerline axes if their roll thrusters were fired to do so, even with their unequal-length-and-mass booms deployed. (Pioneer 10’s and 11’s booms are also of unequal length and mass; they each have two identical RTG booms and one longer, narrower, and lighter vector helium magnetometer boom.) Once the Voyagers were established in spin-stabilized mode, the thrusters–and thus the thruster propellant heaters–wouldn’t need to operate constantly, thus conserving their dwindling RTG power reserves.

    • Antonio March 8, 2020, 14:54

      According to Wikipedia, only Canberra can communicate with the Voyagers. But it’s strange to me that a 70m dish can and a 64m one can’t.

      https://en.wikipedia.org/wiki/Parkes_Observatory#Historical_non-astronomy_research

      OTOH, CSIRO’s website says “Because of Voyager 2’s location and distance from Earth, CDSCC and the Parkes telescope are the only facilities in the world that are capable of having contact with the spacecraft” but it’s not clear what “having contact” exactly means. Only receiving data is ever mentioned for Parkes.

      https://www.csiro.au/en/News/News-releases/2018/Were-all-ears-as-Voyager-2-goes-interstellar

      • Ron S. March 8, 2020, 17:36

        I can only speak in general and not about Parkes specifically so I hesitated to say anything. There are a couple of potential issues.

        First, it is not a trivial matter to install transmitting equipment dedicated to radio astronomy (reception) and be able to dynamically switch between receive and transmit. They may not have the basics in place to make this feasible or feasible in the near term or have it in their operating plan. I don’t know.

        Second, it would require advance scheduling and rearrange booked time at Parkes. NASA might not even have made the request. If they believe an actionable fault with the satellite is low probability or, if it occurs, low priority due to the satellite’s remaining useful life they would not make the request.

        People at Parkes or NASA would know.

        • James Jason Wentworth March 12, 2020, 6:14

          That, Ron S., I’m afraid (although I can see and understand the other side of it), may be NASA’s collective, official attitude toward the Voyagers now, as it was toward Pioneer 10 and 11 in their latter years. *WE* root for the Voyagers, as do their mission personnel (ditto for Pioneer 10 and 11 before they passed out of range and went silent, respectively [although in reverse chronological order; Pioneer 11 fell silent first, in 1995, while Pioneer 10 went out of DSN signal detection range in 2003]), because they’re the only spacecraft returning data from ever-deeper regions of interstellar space (as New Horizons also will), and:

          Voyager 1 & Voyager 2 are also–for most of us here, I suspect–part of our youths, and having them *still* exploring out there, long past their–and our–younger years, is emotionally very appealing (which ^none^ of us should feel the least bit silly or embarrassed about!), but:

          From NASA Headquarters’ point of view, the Voyagers are long past their outer planets-exploring heyday. They’re certainly glad that both probes are still returning data (although some individual NASA–and perhaps even JPL–officials might prefer to spend the Voyager funds on new projects instead). Also:

          They don’t mind continuing to fund the Voyagers’ operation because the marginal cost each year is so relatively low for the new data received (and because even their “Earth people” cost no more to pay to keep the Voyagers going, as they–or at least a lot of them, while some will retire instead–will move on to other space probe projects [some may already also work in other JPL projects] when the last Voyager dies). But when that happens, NASA will not mourn their loss (JPL will feel some loss, being so intimately involved with the project); both will commemorate the spacecraft’s achievements and praise their amazing longevity and long scientific service (as well as the ingenuity and true grit of the long-serving people who made it possible), and then NASA–and JPL–will move on.

  • ljk March 9, 2020, 17:24

    Review: The Vinyl Frontier

    One of the best known aspects of the Voyager missions is the “golden record” included on the two spacecraft with photos and audio from Earth. Jeff Foust reviews a book that recounts how that album came together.

    Monday, March 9, 2020

    https://www.thespacereview.com/article/3894/1

    And what of the record itself? Scott, a record collector who interjects throughout the book about his own experience playing in bands and creating mixtapes, offers a few critiques: he’s not fond of passage from Stravinsky’s “Rite of Spring” included in the record, but a Beethoven piece, Cavatina from String Quartet No. 13, gets a ringing endorsement.

    “Another point I’d like to make is a simple one: this about how bad this record could have been,” he writes near the end of the book. “The whole thing could have been absolutely strangled by committee, or could have become sponsored and commercialized, turned into little more than a record-label advertisement or back-catalogue sampler.” So, perhaps, the Voyager Golden Record did show humanity on a good day after all.

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