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Amateur Records the "Sound" of Mars Express

kdawson posted more than 4 years ago | from the music-of-the-artificial-irregular-shapes dept.

Space 52

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."

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Let me guess.... (1)

tpstigers (1075021) | more than 4 years ago | (#31385862)

"Send More Chuck Berry."

I need a subject? OK (1)

Jinky (565098) | more than 4 years ago | (#31385880)

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.

Re:I need a subject? OK (4, Funny)

Dachannien (617929) | more than 4 years ago | (#31385900)

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 [wikipedia.org]

Re:I need a subject? OK (1)

TheJokeExplainer (1760894) | more than 4 years ago | (#31386884)

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

Re:I need a subject? OK (2, Funny)

Ethanol-fueled (1125189) | more than 4 years ago | (#31385902)

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

It sounds like Wile E. Coyote falling off of a cli (4, Funny)

Oxford_Comma_Lover (1679530) | more than 4 years ago | (#31386016)

> 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.

Falling may not be a bad description (1)

KlaymenDK (713149) | more than 4 years ago | (#31387664)

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

Re:Falling may not be a bad description (1)

ivonic (972040) | more than 4 years ago | (#31388276)

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

Re:Falling may not be a bad description (2, Insightful)

sandertje (1748324) | more than 4 years ago | (#31390824)

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 ;-)

Re:I need a subject? OK (0)

Anonymous Coward | more than 4 years ago | (#31385908)

Yeah, too bad it wasn't something like a loud, slow, bloop. That would be pants shittingly cool.

Re:I need a subject? OK (4, Funny)

AnotherUsername (966110) | more than 4 years ago | (#31386170)

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

Re:I need a subject? OK (1)

TheJokeExplainer (1760894) | more than 4 years ago | (#31386400)

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

Re:I need a subject? OK (0)

Anonymous Coward | more than 4 years ago | (#31386450)

Actually Robin Williams played Mork, not the planet Ork.

Re:I need a subject? OK (4, Funny)

nextekcarl (1402899) | more than 4 years ago | (#31386454)

Thanks a lot. Now I feel old...

Re:I need a subject? OK (2, Informative)

hldn (1085833) | more than 4 years ago | (#31386508)

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

Re:I need a subject? OK (0)

Anonymous Coward | more than 4 years ago | (#31387792)

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

And I just saw an episode of M*A*S*H on TV.

Re:I need a subject? OK (1)

Random Destruction (866027) | more than 4 years ago | (#31395970)

And I thought Edward Winter was dead!

Re:I need a subject? OK (1)

elrous0 (869638) | more than 4 years ago | (#31400640)

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.

Re:I need a subject? OK (0)

Anonymous Coward | more than 4 years ago | (#31386252)

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

"This transmission is copyright by the RIAA and its duly authorized agents. Unauthorized recording and/or distrubution is subject to prosecution under the laws governing copyright in your jurisdiction. Remember, Sophisticated Sophonts Don't Pirate Scientific Data."

Re:I need a subject? OK (0)

Anonymous Coward | more than 4 years ago | (#31386470)

The message is clear when you play it in reverse...

Re:I need a subject? OK (1)

sentientbeing (688713) | more than 4 years ago | (#31390650)

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

What was in that carrier? (2, Informative)

Announcer (816755) | more than 4 years ago | (#31386718)

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.)

You call that an antenna? (-1, Offtopic)

Anonymous Coward | more than 4 years ago | (#31385912)

Hey, wash that off before you put it back.
Oh yeah.

Gay Ninja (-1, Troll)

Anonymous Coward | more than 4 years ago | (#31385950)

Ever met a gay ninja clutching a dashing jeweled purse the size of a napkin and as dainty as one?

Re:Gay Ninja (-1, Troll)

Anonymous Coward | more than 4 years ago | (#31386108)

Dammit Grandpa, I asked you before not to look for dates at the sites I post on. Just use the dog and peanut butter like usual.

DeCSS (0)

Anonymous Coward | more than 4 years ago | (#31386004)

My first guess is that frequency tone and pitch changes are how the data is encoded. The background noise is the interesting part.

Re:DeCSS (2, Interesting)

Ethanol-fueled (1125189) | more than 4 years ago | (#31386162)

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.

There's obviously no advanced life forms there... (0)

Anonymous Coward | more than 4 years ago | (#31386188)

The start of the file sounds like they're using dial-up.

not much to say (1)

v1 (525388) | more than 4 years ago | (#31386390)

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?

Re:not much to say (1)

NixieBunny (859050) | more than 4 years ago | (#31386476)

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.

Re:not much to say (2, Informative)

Anonymous Coward | more than 4 years ago | (#31386804)

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..

Re:not much to say (1)

v1 (525388) | more than 4 years ago | (#31390508)

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.

Re:not much to say (1)

NixieBunny (859050) | more than 4 years ago | (#31391664)

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.

Audio sampling (0)

Anonymous Coward | more than 4 years ago | (#31386394)

Am I the only nerd that thought the clip sounded like a time-stretched version of http://www.youtube.com/watch?v=LC9RJ_SCRfM#t=1m08s ?

With references like that at my hand, I have no idea why I'm at home on a Saturday night.

Hire him (3, Insightful)

acid06 (917409) | more than 4 years ago | (#31386468)

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.

Re:Hire him (1, Insightful)

arthurpaliden (939626) | more than 4 years ago | (#31386660)

actually he will probably be charged with copyright infringment.

Re:Hire him (1)

nacturation (646836) | more than 4 years ago | (#31387798)

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

Re:Hire him (2, Interesting)

tftp (111690) | more than 4 years ago | (#31386782)

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 [kuhne-electronic.de] . This guy, motivated and all, was mostly using off the shelf equipment. For example, look at these photos [ham-radio.com] of ham rigs - and note that those are mobile setups because the rules of the contest encourage roving.

Where is the kaboom? (0)

Anonymous Coward | more than 4 years ago | (#31386688)

There was supposed to be an earth-shattering kaboom!

Wait (2, Funny)

JumpDrive (1437895) | more than 4 years ago | (#31386928)

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)

Re:Wait (0)

Anonymous Coward | more than 4 years ago | (#31387208)

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

Sorry about that. It was supposed to be a harmless neighborly prank, in retaliation for him shooting out my porch light.

I was shocked when he thought it was real and turned this into an international incident.

However, the proof of course is that when you listen carefully you'll hear the Morse code I planted on the carrier.
I guess he didn't notice, but once you know it's there it's hard to miss.

... --- ...

I can make that noise with my short wave radio! (2, Insightful)

Anonymous Coward | more than 4 years ago | (#31387360)

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

I can make that noise on my short wave radio! (0)

zunipus (946278) | more than 4 years ago | (#31387392)

Seriously. A noise anyone can make by twiddling with their short wave radio is worth publishing?

Ham radio types are a bit like audiophiles (2, Insightful)

grimsnaggle (1320777) | more than 4 years ago | (#31387590)

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.

Re:Ham radio types are a bit like audiophiles (1)

thephydes (727739) | more than 4 years ago | (#31387872)

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.

Re:Ham radio types are a bit like audiophiles (1)

ctrl-alt-canc (977108) | more than 4 years ago | (#31387974)

> 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...

Re:Ham radio types are a bit like audiophiles (1)

TeknoHog (164938) | more than 4 years ago | (#31388708)

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.

Re:Ham radio types are a bit like audiophiles (0)

Anonymous Coward | more than 4 years ago | (#31390202)

"What many people do not realise is that hams have often been at the forefront of communications technology. "

That does not mean that the technology was developed as part of amateur radio. Sure, lots of technology developers also happen to be hams, but ham radio, per se, isn't really a technology leader. What ham radio is good at is improvising ways to do things on a personal scale, without needing large corporate infrastructure. Building a dish antenna and electronics to receive Mars Express is straightforward proposition if you have a team of 100 people and millions of dollars. Doing it by yourself in the garage with surplus junk equipment is an impressive accomplishment.

If you look at a lot of the things that are commonly thought as being "developed by hams", it wasn't the concept, it was the clever execution. In that sense hams are more like amateur rocket enthusiasts.

Stuck up much? (0)

Anonymous Coward | more than 4 years ago | (#31389514)

Your entire post came off as you being pedantically stuck up. Get your nose out of the air and appreciate that HE did this before you thought of trying it with your 'superior' gear.

Frohike! (0)

Anonymous Coward | more than 4 years ago | (#31388342)

Was sure lone gunmen were not dead..

Aww... (1)

Taibhsear (1286214) | more than 4 years ago | (#31406032)

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

That's what she said.

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