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Amateur Records the "Sound" of Mars Express

Posted by kdawson on from the music-of-the-artificial-irregular-shapes dept.

gyrogeerloose writes "A French amateur radio operator who built his own ground station using equipment from an abandoned telecom uplink site has listened in on the ESA's Mars Express space probe. While his antenna is too small to allow him to download actual data, he was able to record and convert the signal of the probe's X-Band transmitter into an audio file."

34 of 52 comments (clear)

  1. I need a subject? OK by Jinky · · Score: 1

    Neat, but the audio file really wasn't worth attempting to listen to. I wonder what data would actually have been transmitted in that bit of sound? Where it came from is kind of awesome though.

    1. Re:I need a subject? OK by Dachannien · · Score: 4, Funny

      I wonder what data would actually have been transmitted in that bit of sound?

      http://en.wikipedia.org/wiki/File:Portal-2-ARG-SSTV-Images.png

    2. Re:I need a subject? OK by Ethanol-fueled · · Score: 2, Funny

      It sounds like Wile E. Coyote falling off of a cliff.

    3. Re:I need a subject? OK by AnotherUsername · · Score: 4, Funny

      Mork, calling Orson. Come in, Orson. Mork, calling Orson. Come in Orson...

      --
      I don't like Linux. This doesn't make me a troll.
    4. Re:I need a subject? OK by TheJokeExplainer · · Score: 1

      For those born after 1982, this is a reference to the Happy Days spinoff sitcom Mork & Mindy, where Mork from the planet Ork (played by Robin Williams) is an alien sent to Earth on an observation mission by his superior Orson.

      --
      visit my pal the xkcd explainer!
    5. Re:I need a subject? OK by __aasqbs9791 · · Score: 4, Funny

      Thanks a lot. Now I feel old...

    6. Re:I need a subject? OK by hldn · · Score: 2, Informative

      better pick a later year, as i recall watching mork & mindy on nick at nite well into the 90s.

      --
      http://www.accountkiller.com/removal-requested
    7. Re:I need a subject? OK by TheJokeExplainer · · Score: 1

      This is a reference to the encoded pictures in the dinosaur .wav files that were put into the recent March update of the Valve game Portal which were teasers for the upcoming Portal 2.

      --
      visit my pal the xkcd explainer!
    8. Re:I need a subject? OK by sentientbeing · · Score: 1

      "All these worlds are yours except Europa, attempt no landing there"

      --

      ------
      beware he who would deny you access to information, for in his mind he dreams himself your master
    9. Re:I need a subject? OK by Random+Destruction · · Score: 1

      And I thought Edward Winter was dead!

      --
      :x
    10. Re:I need a subject? OK by elrous0 · · Score: 1

      Ah, those were the days. Back then, Robin Williams was only 20% hair and people actually thought he was more funny than annoying--if you young folks can believe that.

      --
      SJW: Someone who has run out of real oppression, and has to fake it.
  2. It sounds like Wile E. Coyote falling off of a cli by Oxford_Comma_Lover · · Score: 4, Funny

    > It sounds like Wile E. Coyote falling off of a cliff.

    Well, a good space program teaches that some things are constant everywhere in the Universe.

    Beep, beep.

    --
    -- IANAL, this isn't legal advice, and definitely isn't legal advice for you. Also, Squee!
  3. Re:DeCSS by Ethanol-fueled · · Score: 2, Interesting

    Learn to doppler. Refer to the picture in TFA. See that green shit at the top? The "mesa" is the noise and the peak is the tone we hear. As the spaceship flies outta sight, the peak will shift left while decreasing in height. The purple-colored graph is a record of the signal strength over time.

  4. not much to say by v1 · · Score: 1

    Sounds like a dead carrier, with the expected doppler shifts. The carrier is certainly strong enough to get data off from it if there were any. Probably just his bad luck that it wasn't actually uplinking any data during his short window of opportunity to record it.

    I'd imagine a lot of that window was simply reliant on getting the aim for the antenna right and holding it on target. He was using a star tracker I assume?

    --
    I work for the Department of Redundancy Department.
    1. Re:not much to say by NixieBunny · · Score: 1

      Whether the carrier is strong enough depends on the bandwidth of the signal. The downlink apparently (Google is being stubborn) uses phase shift keying at a selectable data rate from a few bps to a couple hundred kpbs, depending on conditions.
      So you'd have to have a suitable demodulator to get the data, and the big message given by the fine article is that you'd need a much bigger dish to get enough S/N to have anything to demodulate.
      I work on radio telescopes, not deep space monitors, so I don't know squat about the demodulation.

      --
      The determined Real Programmer can write Fortran programs in any language.
    2. Re:not much to say by Anonymous Coward · · Score: 2, Informative

      low rate data is BPSK modulated on a subcarrier which is then phase modulated on the main carrier with a mod index (or deviation) that is chosen to balance the power in the "data" and the power in the "carrier". Since the carrier power is used for navigation (e.g. the Phobos flyby) you don't suppress it all.

      All is revealed in documents at http://www.ccsds.org/ or http://deepspace.jpl.nasa.gov/dsndocs/810-005/

      Knock yourselves out... you'll be able to demodulate the bits, do the decoding, find the frames.. after that it's a bit tricky to find the science data and decommutate it..

    3. Re:not much to say by v1 · · Score: 1

      so I don't know squat about the demodulation.

      I'm the other way around, I know radio but nothing about space. For me, with signals like FM, usually if you can hear the carrier you can lock onto it and decode the modulation. That's what phase-locked-loops and tuned circuits are for. I've dealt with many cases of extremely noisy and low signal FM and still been able to get some modulation out of it when I couldn't even hear the carrier on sideband. I'm just very surprised they couldn't get any data out of such a strong carrier.

      --
      I work for the Department of Redundancy Department.
    4. Re:not much to say by NixieBunny · · Score: 1

      Noise is proportional to the square root of bandwidth. The signal-to-noise ratio determines the bandwidth of the signal that can be demodulated. So if they're transmitting a 1Mbps modulation scheme, then the bandwidth would be several tens of kHz and carrier has to be strong enough to present a reasonably noise-free signal of those tens of kHz bandwidth to the demodulator.
      On the other hand, if it's a 3bps modulation scheme, then the carrier could be nearly invisible and still have the necessary S/N to present a useful signal to the demodulator, since the receiver bandwidth can be reduced to under 1 Hz.
      So unless you know the modulation bandwidth, it's impossible to say how much carrier you need to recover the modulation.

      --
      The determined Real Programmer can write Fortran programs in any language.
  5. Hire him by acid06 · · Score: 3, Insightful

    If this guy has so much motivation trying to do this as a hobby, ESA should step forward and hire him straight away.
    Imagine what he could do if he had access to proper equipment.

    1. Re:Hire him by arthurpaliden · · Score: 1, Insightful

      actually he will probably be charged with copyright infringment.

      --
      Undetectable Steganography? Yep, there's an app fo
    2. Re:Hire him by tftp · · Score: 2, Interesting

      If this guy has so much motivation trying to do this as a hobby, ESA should step forward and hire him straight away.

      There are many hams who build their own microwave radios for 10 or 24 GHz (and for other bands too) from parts. This guy, motivated and all, was mostly using off the shelf equipment. For example, look at these photos of ham rigs - and note that those are mobile setups because the rules of the contest encourage roving.

    3. Re:Hire him by KlaymenDK · · Score: 1

      Heck, there are even guys out there who hand build their own radio tubes...
      http://www.youtube.com/watch?v=gl-QMuUQhVM

      --
      "Good news, everyone!"
    4. Re:Hire him by nacturation · · Score: 1

      So his first motion before the court will be to change the venue to where the content was created... in Mars orbit.

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      Want to improve your Karma? Instead of "Post Anonymously", try the "Post Humously" option.
  6. What was in that carrier? by Announcer · · Score: 2, Informative

    The article does explain it. I read about it the other day, that they commanded the craft to stop sending data, and only send a steady carrier. They will measure the very tiny variations in the doppler shift that the Phobos flyby caused, to determine the composition and distribution of its mass. (Is the core hollow, that kind of thing.)

    --
    Willie...
  7. Wait by JumpDrive · · Score: 2, Funny

    Is he sure that was MARS Express and not his next door neighbors high speed power drill?

    Are we sure he did an off axis test? ( I saw that in a movie once)

  8. I can make that noise with my short wave radio! by Anonymous Coward · · Score: 2, Insightful

    This 'sound' claim gets today's WTF Award for its massive HUH? factor. Seriously? This typical shortwave radio noise is worth publishing?

  9. Ham radio types are a bit like audiophiles by grimsnaggle · · Score: 2, Insightful

    They'll often spend enormous sums of money and huge amounts of time trying to do something. Many try to communicate around the world on five watts (DXers) or try to bounce their signal off the moon (EME).

    The difference, however, is that usually the amateur radio types also happen to have instruments that can provide some measure of success. The also tend to do things that are far cooler than having a vacuum tube amplifier.

    But maybe I'm biased... I'm an amateur radio operator, after all.

    That said, I think hams usually try and decode the signal they receive. Just hearing it come in from the air is a little bit less exciting.

    1. Re:Ham radio types are a bit like audiophiles by thephydes · · Score: 1

      Yes. We are often misunderstood as a bunch of weirdo's who talk in code or persist with "dead" technologies such as CW. What many people do not realise is that hams have often been at the forefront of communications technology. So, am I surprised to read a story like this one - No. Am I surprised to hear the derision of slashdotters who think that communications technology started with the mac plus (replace mac plus with your favourite piece of technology) - No again. Geez guys for a bunch that are supposed to be interested in technology, some of you are acting like retarded ferrets.

    2. Re:Ham radio types are a bit like audiophiles by ctrl-alt-canc · · Score: 1

      > What many people do not realise is that hams have often been at the forefront of communications technology.
      From the amount of surplus equipment used by radioamateurs, it seems to me that they are quite on the trailing edge of technology...

    3. Re:Ham radio types are a bit like audiophiles by TeknoHog · · Score: 1

      From the amount of surplus equipment used by radioamateurs, it seems to me that they are quite on the trailing edge of technology...

      Well, I see open source people doing cool new things with old hardware, while shiny new machines are being wasted on MS Office at most workplaces.

      --
      Escher was the first MC and Giger invented the HR department.
  10. Falling may not be a bad description by KlaymenDK · · Score: 1

    If the carrier sound is decreasing in frequency, that should indicate that the probe is accelerating, which, in space, is very much like falling.

    --
    "Good news, everyone!"
    1. Re:Falling may not be a bad description by ivonic · · Score: 1

      Or it could just be a straightforward doppler effect with it moving away from the receiver?

      --
      Grand Theft Wiki
    2. Re:Falling may not be a bad description by sandertje · · Score: 2, Insightful

      It's probably just an effect of it's highly eccentric orbit around Mars. On one end (apoapsis) of the orbit, it's 10,000 km from the surface of Mars, on the other end (periapsis) it's just a mere 298 km from Mars. Moving from apoapsis to periapsis might appear like "falling" towards Mars, and since there's a difference in distance: doppler effect. No need to worry immediately ;-)

  11. Aww... by Taibhsear · · Score: 1

    his antenna is too small to allow him to download actual data

    That's what she said.