back to article Australia down for scheduled maintenance: No talking to Voyager 2 for 11 months

NASA is celebrating the return to full science operations of its ageing Voyager 2 spacecraft by not speaking to the thing for 11 months. After 48 years of service, the 70-metre-wide radio antenna in Canberra, Australia, is due a bit of TLC and will be undergoing upgrades for almost a year. Voyager 2, which is currently …

  1. Paul Crawford Silver badge

    S-band uplink

    The '43' antenna in Australia is special in that is has an optional 400kW S-band high power amplifier, instead of the usual 20kW. A note from the manual (70-m Subnet Telecommunications Interfaces) states:

    400kW Power Amplifier

    2110 to 2118 MHz Only available at DSS-43. Cannot be used above 100 kW without special airspace coordination. No operation below 17 degrees elevation is allowed, no matter what the power is.

    It is uncommon to see general HPA efficiencies above around 40% so they are looking at around 1MW of AC input power just for that amplifier when in use. The smaller 34m dish could be used, in theory, but they would need about 1.6MW of RF power, so around 4MW input AC to run it. And of course the RF route would have to survive 1.6MW without anything flashing over!

    1. AdamT

      Re: S-band uplink

      ... implying that planes going overhead might get a bit warm and/or twinkly? Presumably all the local airborne wildlife has also learned (or been naturally-selected) to go-around when the lights are on...

      1. Phil O'Sophical Silver badge

        Re: S-band uplink

        An antenna that size must have 60+dB gain, so pumping 400kW in would give you a very toasty 400GW ERP. That sounds crazy, are my numbers anywhere near right? If so I can certainly see why they don't want it running below 17deg elevation! I'm not sure wildlife flying into that (very thin, admittedly) beam would have time to notice it getting warm before they were turned into a puff of smoking plasma.

        1. Paul Crawford Silver badge

          Re: S-band uplink

          Very approximately, the power density from that antenna if you are behind the feed is never much more than around 104 W/m^2 which is high, but only about twice the generally regarded safe limit for human exposure at S-band of around 50 W/m^2 (compared to about 1kW/m^2 for full sunlight). Basically the 400kW from the feed is spread over the 70m diameter antenna's 3848m^2 area moderately evenly, then reflected back towards the satellite.

          But that sort of power density will extend a long way out, and is very much higher than would be considered a normal test for any aircraft electronics system!

          1. phuzz Silver badge

            Re: S-band uplink

            "only about twice the generally regarded safe limit for human exposure"

            That sounds fine...

      2. Pascal Monett Silver badge
        Coat

        Re: planes going overhead

        I think that commercial airline traffic is located at a comfortable distance from said antennae and thus, that should not be much of an issue.

        They don't avoid building radio satellite dishes next to airports for nothing.

        1. eldakka Silver badge

          Re: planes going overhead

          As the crow flies, it is only ~10km away from Canberra's airport. Technically it's an international airport, but the international traffic is fuck-all. It is the major regional airport for about ~500k people (~400k in the city of Canberra, and another ~100k from surrounding towns/small cities).

          1. Ken Shabby Bronze badge
            Holmes

            Re: planes going overhead

            I remember in the 90's landing at Hobart "International" Airport and inquiring as to where the destinations were.

            "New Zealand" came the reply. Fair enough, but not any more, apparently.

            1. Anonymous Coward
              Anonymous Coward

              Re: planes going overhead

              Qantas used to sell flights from Hobart International airport at a discount by doing 3 for 2 deals - a Tasmanian could take his wife and sister to NZ and only pay for two people.

              Eventually Tasmanians realised this wasn't a discount and the route was cancelled.

    2. jake Silver badge

      Re: S-band uplink

      "No operation below 17 degrees elevation is allowed, no matter what the power is."

      According to NASA's DSN NOW page, the 43 antenna is currently st 10.40 degrees, and falling. It was at 10.80 when I first read your comment a couple minutes ago. (edit: It seems to have "bottomed out" at 10.38 degrees.)

      https://eyes.nasa.gov/

      https://eyes.nasa.gov/dsn/dsn.html

      1. jake Silver badge

        Re: S-band uplink

        Soon after I posted the above, it cranked itself up to 88.0 degrees, hung out there for a few minutes ... and then went off the air. Presumably they cycled it through it's full reach, and then shut it down (??).

        Have a nice nap, 43. See you in a few months.

      2. Paul Crawford Silver badge

        Re: S-band uplink

        I think the limitation is on the use of the 400kW power amplifier, not the antenna. If it were me, I would be afraid of an accidental misconfiguration or oscillating amplifier pumping out the full 400kW at low elevation even when the modem was supposedly configured for 20kW or less.

    3. Anonymous Coward
      Anonymous Coward

      Re: S-band uplink

      My guess is that on the eastern side the horizon is higher than 17 degrees anyway. It's a pretty big hill, and I live on the other side of it. I've taken my kids to the tracking centre several times, there is a pretty good (but small) museum thingy.

  2. Anonymous Coward
    Anonymous Coward

    You're safer out there

    Meanwhile we're going into self-isolation. Send postcards.

  3. Andy The Hat Silver badge

    Apply your own accent ...

    "Can-berra"

    ... hissss ...

    "Come in Can-berra"

    ... hissss ...

    Dum dum dum ...

    *_click_* "Apologies Voyager 2. Your call is important to us and will be dealt with as soon as possible in line with normal GP appointment sheduling guidelines. You are currently NUMBER 1 in the queue ...If you wish to hold your call may be answered by a receptionist between 8 and 8.30am next February ... If your circuits have suffered a hiccup, please try rebooting. Returning for a service due to any sort of cough is right out ..."

    1. Sorry that handle is already taken. Silver badge

      Re: Apply your own accent ...

      For a moment, I imagined the "... hissss ..." was the noise emitted by a Canberran after hearing Canberra pronounced "Can-berra".

  4. Yet Another Anonymous coward Silver badge

    Down Under?

    Yet more NASA "spherical Earth" propaganda

    1. Annihilator Silver badge

      Re: Down Under?

      According to some flat earthers, Australia doesn't exist and that everyone from Australia is an actor. Anyone visiting there is living in some sort of Truman Show style setup.

      1. Yet Another Anonymous coward Silver badge

        Re: Down Under?

        Australia, the place where the mice are 2m tall and hop on giant legs while keeping their babies in a pouch? Where every spider can kill an elephant with a single bite? Where it is all desert but burns down every summer?Where there are 1000s of kms of perfect beaches but you get eaten by a shark / stabbed by a fish if you set foot in the water?

        No that's a totally real place mate, defo .....

        1. 0laf Silver badge

          Re: Down Under?

          Is this why there are no elephants in Australia?

        2. phuzz Silver badge

          Re: Down Under?

          Don't forget the drop bears.

        3. MyffyW Silver badge

          Re: Down Under?

          ..and the Koalas riddled with chlamydia

          1. Anonymous Coward
            Anonymous Coward

            Re: Down Under?

            "..and the Koalas riddled with chlamydia"

            If you think that's bad, don't even think of touching a Queenslander...

            1. Muscleguy Silver badge

              Re: Down Under?

              They have a strange sort of obesity in Queensland due to the temperature they drink their brown liquid at. Their spare tyres are very high up around the stomach (the organ) just under the rib cage.

              The ice cold 'beer' they drink in such quantity chills the stomach so much the body seeks to lay down thermal protection around it. Since evolution has yet to accommodate ice cold liquids vs cold environments this thermal protection is insufficient. But since the stimulus is often ongoing for many years quite thick spare tyres can be seen. You get bandy legged otherwise trim old guys with this weird spare tyre.

        4. Muscleguy Silver badge

          Re: Down Under?

          You forgot 9 out of the 10 most venomous land snakes in the world. Then there are the sea snakes . . .

          There are also the nasty fire ants. I was pleased with my thick high jandals (flip flops) as I passed some on the footpath on my visit to Canberra back in the '80s. I had a nice run up the Black Mountain where they keep the observatory.

          I should note that the fire ants were most dangerous wildlife I saw during my visit though one of our party stepped on a snake whilst bathing in Lake Burley-Griffin. Said snake simply swam off. Whilst there we helped persuade a local scientist to relocate to our alma mater in Southern New Zealand. He was the internal examiner of my PhD thesis.

  5. Marketing Hack Silver badge
    Alien

    A lot can happen in 11 months!!

    What if you regain contact with Voyager 2 next year, and the only reply you get is something about "This is V'ger. I search for the creator!"

    1. NeilPost Bronze badge

      Re: A lot can happen in 11 months!!

      Fortunately Prime Timeline Kirk is still alive. I think. V’ger would obliterate Chris Pine and his Kelvin timeline deviants.

    2. MyffyW Silver badge

      Re: A lot can happen in 11 months!!

      maybe it will have kitted itself out with variable-geometry narcelles and bio-neural circuitry?

  6. Anonymous Coward
    Anonymous Coward

    Goodbye Earthlings

    Presumably Voyager will interpret the lack of incoming comms as being indicative that humanity has finally destroyed itself? I wonder what it will do then? Find some intergalactical species to offer it a new home?

    1. MyffyW Silver badge
      Coat

      What will it do?

      Follow letters-of-last-resort protocol and put itself at the disposal of the Australians?

      Mine's the one with a copy of On The Beach in the pocket.

    2. Muscleguy Silver badge
      Alien

      Re: Goodbye Earthlings

      It has recently left this solar system, invoking intergalactic aliens is rather wide of the mark. I know we are out here on the less fashionable end of the Western Spiral Arm but Intergalactic?

      Merely interstellar aliens would be much more likely.

  7. HildyJ Silver badge
    Angel

    No more spam

    Voyager must be overjoyed. Eleven months without having to clear its spam folder.

    Now if Australia can do its maintenance without the antenna being burned up in a brush fire, all will be good.

    1. Anonymous Coward
      Anonymous Coward

      Re: No more spam

      The Stromlo Observatory is a very short distance away and it did get destroyed in a bush fire in 2003. So yes these things can and do happen.

  8. nmcalba

    The Deep Space network

    An interesting site that I often like to have a glance at is https://eyes.nasa.gov/dsn/dsn.html

    You can see what part of the deep space network is talking to what satellite/probe - and the data rate etc.

    1. Muscleguy Silver badge

      Re: The Deep Space network

      When I first heard the term Deep Space network as a teenager I imagined a set of relay spacecraft strung out along the solar system. When I learned it was just a set of geographically spaced radio telescopes I was somewhat disappointed.

      It still seems a rather over grandiose title. The edge of our solar system is hardly deep space in the wider scheme of things.

      It's SETI which has tried to do the real Deep Space stuff, not NASA.

  9. Sanguma Bronze badge

    Tidbinbilla!!!

    So nice to hear from it again.

  10. Anonymous Coward
    Anonymous Coward

    Come in number 2

    Your time is up!

  11. Jemma Silver badge

    So

    We have a transmitter that is working - albeit a bit flakey at the moment - and a spacecraft which by all realistic standards is well beyond its service life but is miraculously still communicating.

    We *know* what we need to manufacture and install and the changes we need to make to the transmitter - so why on earth are we risking the spacecraft for *months* uncontrolled when we could build out the transmitter components offline, test them as much as possible, bring them to the site and slap them in with the minimum downtime? Or am I missing something?

    This system is an utterly unique resource and losing our ability to control it for months when there are other options seems criminal to me. Yes it has error correction and other systems on board but nothing to what human system engineers can accomplish.

    Im seeing far too much of the "Columbia" spirit here - aka "don't worry, it'll be fine"..

    Or to quote

    "If nothing else works, a total pig- headed unwillingness to look facts in the face will see us through."

    Mixed with, to paraphrase

    "We're taking an awful risk here, this had better work..."

    I just can't see this ending well.

    1. dvhamme

      Re: So

      I would hope they had a look at the most likely failure modes and concluded that just about all of them are either unfixable, or can still be fixed after 11 months? It's not like the thing is suddenly going to veer off course and need a human pilot to grab the stick and steady the bird... Even if it were, I don't want to imagine what Battlefield 1942 multiplayer with a ping of 16h feels like.

      Let's just hope it's not going to gradually fill the outbox because Earth's mail server is failing to send delivery confirmation...

    2. John Brown (no body) Silver badge

      Re: So

      "Or am I missing something?"

      Likely it's a full overhaul, not just transmitter electronics. There's a lot of metal and engineering involved in a dish that size. Maybe rust, maybe new actuators, maybe re-coating the entire dish aqnd a fresh protective coat of paint over the whole structure.

  12. Champ

    The Dish

    Is this the same dish that we the title star in the movie, er, "The Dish", starring Sam Neill?

    Quite a nice little picture, that

    1. Ken Shabby Bronze badge

      Re: The Dish

      That would be Parkes radio telescope.

      About Parkes radio telescope

    2. Muscleguy Silver badge

      Re: The Dish

      Don't forget Quiet Earth, though that one might be too niche New Zealand. Not sure it got much wider distribution.

      1. Long John Brass Silver badge
        Windows

        Re: The Dish

        The Quiet Earth; Fantastic movie Bruno at his best!

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