Pinging The Voyager 2 Probe (PART 2)

Inside the new NASA/CSIRO Canberra Deep Space Communication Complex control room at Tidbinbilla, and the technical details of how they contact the Voyager 2 space probe. Look at the live data and spectrum displays!
Follow Richard on Twitter @nascom1
Tech details on the communications:
descanso.jpl.n...
PART 1: • How To Contact The Voy...
Forum: www.eevblog.com...

[@nil2k]

Imagine waiting almost 32 hours to find out if a command you sent was received and understood and executed? I remember being unhappy with 650+ms ping times to Australia from Atlanta.

[@chuckvanderbildt]

Well, this stuff is pure gold. In any of the other videos available on sites like this they always skip over the meat and cut straight to the pudding, but you know your audience, and you're not afraid to go into the details. We want the details. I am really stoked about where this channel will lead you, and us in turn. Kudos, good luck, and thanks!

[@ntesla66]

"The most accurate antenna on the planet..." and you took us there Dave. Thank you! I'm a radio astronomy enthusiast so I had no problem following his most excellent explanations. If you can, it would be great if you tell that man "THANK YOU!" for doing such an excellent job of explaining it all.

[@EEVdiscover]

Will do! I'll send him a thank you gift.

[@jimmuehlberg2153]

Great video! I'd have to take issue with the "most accurate", though, depending on what you mean by accurate. I can assure you, that antenna cannot hold a parabola over the 70 meter diameter! That antenna over my right shoulder is specified to 1 THz. Yes, terra Hertz. They are the "Most Precise" antenna surface in radio astronomy. Anyway, it's not a contest! Probably not fair to compare a 64 element interferometer to a single dish!

[@jimmuehlberg2153]

I see the carrier at about 8 GHz, so the dish doesn't have to be that "smooth"...

[@jimmuehlberg2153]

I meant left shoulder... Forgot to mention, that's the ALMA array in the Atacama Desert of Chile.

[@SimoWill75]

James, I believe Richard was referring to pointing/positioning accuracy, not the dish's figure.

[@diyhouse]

This is a great video,.... The guy doing the commentary really knows his stuff,.. I just soaked up his tech speak,.. none of this mamby pamby stuff that is "softened down " for TV,.. send this guy a big Tx from all us nerds out here...

[@pocoapoco2]

How the hell do you keep an antenna that big to less than 2 millidegrees tollerance? I would think on a partly cloudy day when the sun shines on just part of the antenna thermal expansion would throw it off much more than that.

[@tuxontour]

Sentence of the week: "152 I'll be jumping up with joy and I will think oh my god it has turned around and heading back"

[@RoamMeYo]

I was searching for this comment :) thanks, else I would have put it :D

[@pcuser80]

This is so nice. So far away and still contact.... respect

[@Blowcrafter]

rf stuff is just a black art :/

[@stephengloor8451]

Really interesting and the technical detail was spot on. Will watch anything like this where the tech is explained so well.

[@vincei4252]

Bloody ripper! Dave, will we get to see the hardware? The LNA's and the cryogenic cooling systems? excellent stuff!!!

[@redsquirrelftw]

That would make a great teardown!

[@pekkagronfors7304]

You must give the vids a number. #1, #2. Otherwise it is going to be impossible to refer to them when numbers of vids grows.

[@Mr.Laidukas]

loved music and time lapse at the end!

[@karlh.peterson8134]

Great! Did I hear Gammell asking questions there? You guys should consider cooping and Chris might tackle opportunities in the states, after all he is apparently part of the channel launching already. This would probably open more doors too as a bigger undertaking.The format i think supports that avenue well. IT would be a bit sad if such content would mostly be limited to Australia even though there'll still be plenty to see i'm sure. What sets this apart from the likes of "Discovery" channel is the technical stuff which they skip and after a while everything just looks the same.

[@HonestJunkie]

Maybe a decade ago (circa 2010)... I gifted my girlfriend a brand new iPhone-4 which was promptly stolen that very afternoon in a busy Gloria Jeans. Thanks to my use of 'Find-My-Phone' ...... I can still recall the *RUSH* of Technological Badass Blokeyness I felt after tracking down & then retrieving her new iphone-4. But this ... *THIS* OMFG this is next level next level "So what does your work involve" 2:01 " ... Well currently just Tracking *Voyager 2* ...... & as before we transmitted a number of 'No-Op' commands to the spacecraft ....."

[@user-lp2op9uu1w]

The coolness of this is way bigger than -159 dBm, more like +159 dBm!

[@jerrysweeney9003]

Excellent! Two of my favorite spacecraft. What they are telling us about the solar-deep space barrier and bow-shock wave is amazing for craft made in the '70s. Not to mention what the magnetic bubble looks like that the sun provides that helps protect us for the nasty stuff in deep space. This was a real find of information. Thanks Dave. More please?

[@EEVdiscover]

More on the way.

[@FamilienSoelberg]

So cool, so freaking cool! And fantastic explanations as well!

[@SaturnV2000]

Fascinating! Love it! Three thumbs up!

[@GSR600Relaxed]

Really awesome...love the technical details.

[@dandhcomputers]

very cool video I am glad you did this Dave

[@ottoreuter6279]

The thumbnail is awesome because it's true!

[@EEVdiscover]

Indeed!

[@SopanKotbagi]

Voyager 1 disliked this.

[@gn2b445]

at 1kb per second

[@PointyTailofSatan]

-159dB! wow. It's like picking up a cell phone on Mars.

[@trickyd499]

wow Dave, this was super interesting, thank you so much!

[@RabiBenLavi]

So is that a fail on the CSIRO confusing carrier power readings? When's the tear down? jk

[@JetNmyFuture]

This is the best series of videos I have seen in a long time. Well done Dave! Thank you for capturing this guy and giving us all a peek into the edge of our solar system.

[@georg2010cz]

@EEVdiscover I was hoping for some of the data coming from the v2 being actually made audible as it is being received by the antenna, for this video :D

[@pu1ypj]

Just imagine a troll with a wide band noise generator near there hahahah

[@pu1ypj]

XD

[@Very_Dark_Engineer]

wow, its a one of the most fantastic work places in the world

[@Mark_Bloom]

Wow! Amazing!

[@Cracktune]

this is great stuff!

[@ahpadt]

Hugely interesting. Didn't understand much of what he was saying tho, aside from remembering terms like FEC and doppler from uni. :p

[@leshopski1094]

Cool. Who did you have to sleep with to get let in there?

[@EEVdiscover]

What happens at the CDSCC, stays at the CDSCC.

[@michaelsommers2356]

_"What happens at the CDSCC, stays at the CDSCC."_ Unless it's beamed out of the solar system to Voyager.

[@hexinli]

Really enjoyed this pair of videos - thank you so much for producing them! Can't wait to see what you "find out" next!!

[@douro20]

1 millidegree is 0.2 arcsecond. These things can resolve to 0.1 arcsecond from what I understand.

[@wilfredswinkels]

more of this Dave very interesting!

[@supercybercow5388]

Gotta love OSF/Motif stuff :) First thing in the morning is to start that darned X-server, which in fact is - an client - XD

[@frankbuss]

"-159 dBm, it's huge". Sure :-) Minimum WiFi level is -100 dBm, GPS is -127 dBm. Of course, the required antenna is a bit smaller.

[@17plus9]

What frequencies are they using?

[@sparkplug1018]

And I think the Uplink is 2.1 GHz

[@samik83]

Any idea why they are using such a high frequency? Wouldn't a lower one come through easier?

[@17plus9]

Yeah, that's what I'm wondering too. And 2.1 GHz doesn't really shine in terms of interference avoidance. My guess is that they need high bandwidth for error correction due to lots of distortion. The frequencies shouldn't much of a problem in space with little absorption (I don't know this exactly though). It's more a problem within the atmosphere which is then compensated by power and high gain. Remember that satellite TV uses also high frequencies (12 GHz or so). So there is certainly a technical rationale behind it.

[@17plus9]

Oh okay, that could be. Thanks for the input!

[@kissingfrogs]

Excellent walk thru. Enjoyed the tour.

[@Ganjulation]

Interesting the website had a different power received than on his computer

[@jonahansen]

WOW! Great videos Dave, and kudos to Richard Stephenson for his time and training. He's a one in a million guy - he has to know everything about the system to keep it going, and he does! As ntesla66 said, his are most excellent explanations...

[@pnjunction5689]

Funny, how I ended up with a new job at europe's largest single dish radio telescope after watching this video.

[@network_king]

Not sure why, but I always thought NASA and missions I thought Houston or cape Canaveral. I didn't know they had satellite locations in other countries. I guess makes sense though as signaling is probably a line of site and they probably need 24/7 coverage.

[@joepereira3421]

Enjoyed watching Dave, well done

[@carlzimmerman8700]

Knowing little about RF and communication protocols I found his talk still fascinating, you can tell he loves his work.

[@GegoXaren]

wow...Motif and libx11... that was a long time since those programs were written...

[@tullyfisher]

This is super interesting. Thanks so much for this upload!

[@NickNorton]

All those years and no recap required of course. Voyager 1 & 2. We threw them out there, but we didn't throw them away.

[@hypercomms2001]

04:57..Wow... looks like they are still using SOLARIS ! Who supports it?

[@Adam-bw4lw]

Still faster than my internet speed...

[@boxritter]

Did you need days to load this video?

[@psient]

I wonder if their talent quantify the cumulative value of weight as rain drop impact in a given period shifting position of the antenna and so, representing a distortion in accuracy.

[@asagk]

Doesn't the antenna dish deform over time as a whole? Sort of squatting, loosing shape?

[@glenwoofit]

The page name has changed already. I suppose it makes more sense to have EEV somewhere in the title.

[@stocksj]

Any idea what type of systems and software they use for tracking?

[@peckelhaze6934]

As good as part 1.

[@pcuser80]

I was wondering how about Voyager 1? Also still out there....

[@mikgus]

yes still going to around 2025 (according to wikipedia)

[@mduvigneaud]

My heart is glowing with jealousy! :D

[@abes.4040]

What operating system are they using on those terminals?. it looks like an X window Unix based system

[@lmiddleman]

See kids... serious work is not done with MS Windows.

[@FrozenHaxor]

They still use it down at the LHC :)

[@HampusSandberg]

FrozenHaxor not really, most of the control systems are running versions of the CERN Linux

[@AntoninKral]

Hampus Sandberg exactly. Tk reminds me my time on Phoenix and Compass experiments. CERN linux is basically tuned RHEL. You can also meet a little bit of Debian, or some more obscure stuff like wxworks for real time stuff.

[@FrozenHaxor]

+Hampus Sandberg I was mostly referring to front end. Most systems of such complication use UNIX based backends, that is correct.

[@bennylofgren3208]

The widgets are all good old X11/Motif, meaning the software was probably initially written in the 80's. That was high-end UI design back then. :-)

[@ralon66]

Are there any kind of password when handshaking the deep space probes, or could in theory anybody with a large antenna take over a spacecraft?

[@sparkplug1018]

A while back a group of students was able to lock onto the carrier, but weren't able to transmit or receive anything from it. NASA's explanation implied that there is some form of either security or encryption that prevented that since they didn't have it or know the proper procedure. Still pretty cool that they could pick up and track the carrier though, I believe they were from Germany.

[@WouterWeggelaar]

Reception is well documented, and a group of radio amateurs from Germany decoded Voyager in 2006 with a 20m dish antenna in Bochum. uplinking is a different ball game, but getting the carrier lock is probably not too difficult (depending on your difficulty scale that is). The amount of power you would need is A) not trivial to generate and B) will not go unnoticed. Later spacecraft had better protection on them, and depending on the country that owns it, encryption and/or authentication may be mandatory. In The Netherlands, it is mandatory to protect the control communications.

[@sparkplug1018]

+Wouter Weggelaar Given the description of the system I think you would need to know the correct frame header to actually communicate with them.

[@AttitudeGames]

Did anyone else notice the 8.4GHz Carrier Frequency decreasing, I assume it's to counter the Doppler?

[@TaufiqSunar]

GNOME Desktop Environment over there

[@mogwopjr]

That signal, that very small signal... That IS Voyager! I don't care how small it is, that is something I never thought I would ever see in my lifetime. Thank you Dave and Richard. This is fascinating and amazing. What an absolute treat.

[@Sam-w9des]

I need to hook my amateur radio to that antenna ; ) W9DES

[@yakomiru]

Усилитель хороший: -159,05 db, сигнал/шум 26db , и частота не очень высокая 8,420 ГГц. Хотел бы я там побывать... :)

[@Ybalrid]

That's some good old Unix X Window system on their workstation. Curious about the actual OS running that. A Linux? A BSD? Some other Unix?

[@Adam-eb3rs]

Ybalrid Kristian Dawe I'd like to know too, at first glance maybe a custom windows 95 job. hmm

[@SuEnRoD]

WAY cool!

[@nutzeeer]

Could you connect an oscilloscope to look at the live data?

[@rfengr00]

Wonder what's the isolation on that diplexer? To be transmitting while receiving on that 4K LNA is pretty amazing. I wonder if they have isolation issues between dishes?

[@mixolydian2010]

Always thought, since i was a kid, that Deep Space Tacking sounded so cool! I think its amazing these guys keep track of these objects, that are long lost, in many cases to the public eye, so much science still left in them! Cheer guys and thanks Dave for the video.

[@DiveExplorer]

Great video. Thanks for sharing

[@megasmart1337]

Too bad we dint see any hardware!

[@deathblowhere]

Hey Dave! After all these years you still amaze me! The right stuff! :) Thank you very much!!! PS. Just a little information for you - the EEVblog link you this channel (this tiny little button at the bottom right corner of the channel banner) has an error - "youube" instead of "youtube" ;) Regards, Phil.

[@materialsguy2002]

Ultra stable oscillators, Dave. Elaborate, please. I can imagine DOXCO or rubidium? 1970's tech, DOXCO with extra shielding. HP still be the standard.

[@73Shakes]

Even though I didn't understand a dang word of what was what it was still highly interesting. Hope to more of these types of vids! Thanks for sharing!

[@gonzo_the_great1675]

How do they measure the live noise figure? I assume a switched noise generator in the feed, off the rx freq, but within the LNA bandwidth?

[@MatthijsvanDuin]

Not sure what you mean... the noise is simply the power of what's left of the received signal+noise when you remove the signal (either by subtracting out a reconstructed version, or more simply by just filtering out a narrow band around the carrier)

[@Maescool]

So, there is mentionend they can get signals as low as -170dBm, but what is the actual noise floor of these antennas?

[@MatthijsvanDuin]

The noise temperature mentioned often is a way of expressing the noise floor. A noise temperature of T (K) means a noise power density of kT (W/Hz) where k is the Boltzmann constant. For example a noise temperature of 19 K means a noise power density of 2.6*10^-22 W/Hz which is -185.8 dBm/Hz (I always feel dirty when writing "dBm/Hz" since it's log10(power density in mW/Hz)*10, not a power value in dBm divided by bandwidth in Hz, which would be a nonsense value, but what else would you call it :P )

[@haffolderhaus]

Madness An 8000 ton antenna and this accuracy. I do not think about the wind loads! Sure, the part must also weigh 3 kg (small joke). This Telescope is a really wow!

[@kristiandawe85]

This channel is back up and running :), I knew it wouldn't take long for the channel to back on KZbin, Dave I'm so glad this is now working and I can't wait for more videos, fingers crossed that this channel won't get banned.

[@Spookieham]

That was utterly fascinating Dave - thanks very much for posting that. I must admit that even with an EE degree some of the terminology and concepts were a bit deep but it really showed just how much effort and technology it takes to get a signal from deep space. I went onto the DSN page earlier and sure enough 43 is currently listening to Voyager 2 I really enjoyed the broadcast transmitter tour as well - again it's not an area I am really familiar with so it was very instructional. I look forward to more of these. Please don't "dumb them down" either - there is enough meat in there for us serious engineers but there is plenty in there for those who aren't quite as up to speed with the technical bits. Well done again.

[@fohdeesha]

these were great videos Dave, maybe my favorite of yours in a long time. thanks for the really close up shots on the screens and data, you know that's the kind of shit we want to see! only thing I'm missing is a tour of the rf gear, lna cooling systems etc

[@MikeWaltonPro]

Very cool stuff Dave. Like the new channel. Subbed and looking forward to new info. The side stuff may even be more interesting than 'scope talk'. Keep up the great content.

[@JamesMarsack]

Interesting video! I'm curious about the highlighting of the signaling details for the space craft in this video. Being that the craft was launched a very long time ago (and probably has little or no security protocols), would some unscrupulous individual or group be able to use this information to target the craft and send their own series of C&C to the craft? I'm guessing having a mega antenna is a rather big hurtle to overcome. It's absolutely incredible that these craft are still functional after all this time!

[@zeproo]

since i was a kid i was always trying to find out how they talked with the voyager spacecrafts> this video is really a revelation for me > thanks so much

[@tedvanmatje]

Hi Dave, thanks for posting this and for the new channel too! was waiting for an engineer in the background to shout "focus....you fook" ;)

[@craigs5212]

At one time I downloaded the DSN interface and operations specification. It's is what one would use to design you deep space probe and have it communicate with the DSN. Was very interesting but I can't seem to locate it again but it gave all the details.

[@materialsguy2002]

Dave, thanks for this. And to Richard for a unique insight, wow! I am of the Apollo generation, so this is really meaningful to me.

[@TheDrunkenMug]

AWESOME video Dave :D I absolutely love Radio astronomy and the Voyager crafts !

[@MrSupro]

I have wanted to go see our Goldstone for years but it is a long process to get a tour. Great Video. I would have like to see the raw data from that blazing 160 bps signal!

[@stationplaza4631]

Astonishing that Voyager is still working and that its signal can still be detected....Amazing stuff!

[@pausmth]

Wow, I'm just in awe at the fact we can actually detect and communicate with things that far away.... Wow! Thank you for doing this it's amazing!

[@Raymonkey77]

I'd imagine that they also have to correct for the dipper effect and adjust the carrier for the speed that the voyager spacecraft moving away from us. Definitely have to have some sort of rock solid error correction implimented to adjust for some of the frequency drift.

[@ReneSchickbauer]

Nice series! But damn, when one realizes that he is one year older than the farthest man made object out there...

[@CezaryAkakios]

Loving the old-school Motif UI widgets.

[@FurkanBahadr]

These series are awesome! I'm interested in RF engineering and these videos are really helping me getting confident about what I will do in my career! Thanks Dave

[@cowtheslice]

did you hack voyager 2

[@robertleifeld225]

Thanks for adding the new channel, was good to learn more about Voyager and that it is still doing it's job and that someone on our planet even cares; I do!

[@redsquirrelftw]

Crazy to think how long ago that was sent and we can still talk to it. Or the fact that the power source is still generating.

[@bobbym3155]

how do they avoid interference, like someone malicious blasting on those frequencies?

[@jaakkooksa5374]

Where do they receive signals from Voyager 1? This same station?

[@EEVdiscover]

Sometimes. Usually at Goldstone though. They are in different directions.