Slashdot Mirror
Huygens Wind Experiment Salvaged
SeaDour writes "Earlier, it was reported that the data from a critical wind speed experiment onboard the Huygens probe to Titan was completely lost due to someone forgetting to turn on one of Cassini's communications channels. However, it now appears that ground-based radio telescopes from the National Radio Astronomy Observatory were able to record the transmission's many subtle doppler shifts and reconstruct that lost wind data. The winds altered the probe's horizontal rate of descent, thereby producing a change in the frequency of the signal received on Earth. Additionally, the resolution of the radio telescopes was good enough to track Huygen's position to within one kilometer, allowing for the creation of a three-dimensional model of Huygen's descent."
... nothing like a little backup.
*yawn*
is that if that experiment would have been turned on like it was supposed to, probably nobody here would have ever known that it existed in the first place. ;-)
How can you have a horizontal rate of descent? Was this thing was falling sideways?
What a strange and fantastic world this Titan must be.
.
Let's hope they're not full of hot air.
I hope it's not making a habit that people can forget something and fix it later, it doesn't work every time.
Rock that crushes, Paper & Scissors that don't matter.
That we have equipment sensitive enough to track a probe's position to within *1* km all the way out on Titan..
saying it seems rather bland but when you think of how many millions of miles away it is, I think it's pretty remarkable.
...the scientist who forgot to switch the experiment on, making "wooshing" sounds into a mike. "We got the data back, nothing to be embarassed about here, no sirree!"
Looks like +1 Karma bonus modifier saved someone from a tough time!
Score:-1, Zoom, right over moderator's head.
if anyone at nasa is dumb enough to read slashdot : you guys rock !
Seriously : most people would give up, blaming someone else. It takes a true fighting spirit to try and recover from what someone else has fucked up.
When will I end this grieving ? When will my future begin ?
Everyone has to save Europe AGAIN!
as I am understanding the story of this has been blown out of proportion. The second microphone that was not "switched on" was not there to provide a second data source, only a backup data source in the event of a equipment failure. Redundancy not dual channel. Nice that this experiment now has such a high profile that it would not normally have had. Great work at public relations going on here. Nothing more.
that's the first diagnostic question I always ask when fixing something.
Like Sweepstakes? Try out my service @ http://www.yourpowersweeps.com -- Free 21 day trial, no cc needed.
So basically what they are saying is they should have used the space for some other experiment? The guy spending years setting up an experiment that never got turned on isn't as bad as designing a useless experiment taking up space on the probe. Or was the onboard experiment supposed to be much more accurate?
I Am My Own Worst Enemy
of the movie "Welcome back, Mr. Macdonald" where some japanese guys doing a live radio show lost all electronic equipment and had to resort to follying the special effects. Very funny if you ask me... specially the spaceship part.
well it looks like google hasn't snatched up ALL the smart people.
So.... it was on?
Anyone else a bit puzzled?
Technology, the cause of and solution to all of life's problems.
So, the experiment itself wasn't saved. They just found another way to get the data (reading the doppler shift in the signal).
So, here's a good question: why did they need to include the equipment for the experiment in the first place?
Our kind travels between the stars as an endogenous retrovirus encoded into a modulating radio carrier wave in the 1800 khz range.
i'm just glad professor john frink is finally getting his due. letting him name this probe and mission are going to do wonders for his career, what with the publicity and the notoriety and the ladies and the GLAVEN!!!!!
Frink link
From the very beginning it was reported on here that ground based telescopes would be able to record and reconstruct the data.
This is the first time that I heard them saying that the data was "completely lost".
At least they found a way to reconstruct the data. He and his entire team were probably planning suicide. 20 years of your life down the drain.. Now we'll find out all kinds of important things like the windspeed on Titan... .. ....
They're quite old anyway, basically from the day after it landed. For example mentioned here.
Slashdot chose to post about the doomed mission instead, which made me believe it was indeed lost... but apparently it was like this all the time.
Beware: In C++, your friends can see your privates!
ESA or NASA?
Why we need to have backups for our communications, cables, data if a space mission don't have? I can't see my boss telling me that Huygens don't have backup. Why we can't have to? What is so critical? A space mission or my mp3s on the server?
http://www.michel.eti.br
A lot of this work was done by the "Green Bank Telescope" aka the Great Big Telescope or GBT. You should check out the specs on this telescope. It is the world's largest fully steerable telescope and it is taller than the Statue of Liberty. I was a grad student while this was being built, and was always impressed when I saw presentations about the amount of work that went into creating this instrument. It is not nearly as famous as other telescopes like Hubble or Keck, but is very impressive nevertheless.
For those that can't be bothered to RTFA
The wind speed experiment and both channels on the Huygens probe were turned on. The channel A receiver on the Cassini spacecraft was not. Cassini was relaying the data to Earth (with some delay, I believe).
A ground based radio telescope network (not just the the NRAO) were supposed to pick up the signals direct from Huygens, and use doppler shift measurements of the carrier frequency to calculate rate of descent. The network wasn't intended to actually be able to decode the data from the signal.
It now looks like some, if not all, of the lost data from channel A can actually be recovered from the measurements made on the ground.
I've also heard (but not seen written anywhere) that half the images taken were sent over channel A, and half over channel B. I've no idea if that is true, and if so whether the lost images can be recovered as well.
IIRC about half of the picures taken were relayed via the A channel and what we have seen is all B channel stuff only.
Any chance of reconstructing those images from the ground-based recordings of the A channel, or is the signal so weak that all that can ever be deduced is the carrier frequency, not any data?
earning karma in heaven right now....
Sorry, I had eaten a lot of beans that day and I'm afraid you'll have to recalulate. Lord knows what else I screwed up.
This might seem a little harsh, but why was a wind measuring experiment sent with the probe if we could gather the same data remotely via doppler shift measurements?
I imagine it's not the same data [or rather the same certainty or resolution], but still, wouldn't the space/weight be better spent on a different experiment if the wind study team could make do with the data gathered from doppler shift analysis?
talk about geek status points. The guy who figured that out must be strutting around like a fricken' god or something, or one of those guys in the movies who does the tap-tap-tap-we're in routine.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
Three people have responded to the original poster's question so far. The two who had a nickname attempted to answer his question while the anonymous coward was content to just be a smart-a$$.
Anyway, the article was, of course, referring to the horizontal *component* of the descent.
Don't take it personally DemiKnute...a couple of days ago I got hammered by a lot of AC's just for asking how you could take a picture of something 20K light-years away.
This is probably why "The Sims Online" failed as well.
A goal is a dream with a deadline
the resolution of the radio telescopes was good enough to track Huygen's position to within one kilometer
...the position tracking might not have been done if the world weren't so fired up about processing the data received by the radio telescopes. Sure, there might have been some grad student somewhere who would have analyzed the data sometime in the next couple of years and published the same results, but by then we would have OOH! SHINY!
Fantasic bit of work really, but I bet as just as accurate (or inaccurate, depending if your glass is half full or half empty) as tomorrows weather forecast here on Earth, going by experience...
... of a maxim my team has tried to explain to our senior management many times, without sucess:
"Yes, we will always pull a miracle out of the hat for you when everything goes wrong. But, you should not write your plans with this as an assumption."
~~~~~ BigLig2? You mean there's another one of me?
There a good chance that you may run into a sub-space warp field disturbance.
I'd just use micrometer....
A goal is a dream with a deadline
The Star Trek:TNG writer's manual called for you to use the word TECH every time you needed a word like that; they got their science advisor to fill it in later.
So you really would see scripts with "Captain, I can compensate using TECH to TECH..."
I can't help but think that the series would have been better if TECH hadn't been such a cop-out. Sci-fi is about people, not technology, but often it's about how people interact with technology. If you don't know anything about technology then it's just the way people interact with mumbo-jumbo.
They got it working. The way I see it, the guy who took the picture of the descent for the article must have turned it on for them after the news of it not being turned on reached him.
It really blows.
This hasn't gotten as much coverage, but a design oversight nearly cost all Huygens data. Doppler shift was not accounted for in the signal decode process. The mission plan had to be rewritten to find an alternative flight path that reduced the Doppler shift to within the limited acceptable tolerances. Fortunately, Cassini's approach to Saturn was accurate enough that enough fuel existed to allow this while preserving the latter part of the existing flight plan.
e /oct04/1004titan.html
Of course, in retrospect, maybe earth-based monitoring would have come to the rescue in this event, in an even bigger fashion.
"Titan Calling: How a Swedish engineer saved a once-in-a-lifetime mission to Saturn's mysterious moon"
http://www.spectrum.ieee.org/WEBONLY/publicfeatur
Sorry if this is a repeat. Slashdot's search 503-ed on me.
to point the telescopes there in the first place?
Can you be Even More Awesome?!
... ahhhhhhhh
come on fhqwhgads
It would br great if we were to get a 3D model of the descent vector rendered in 3d which we can view from several angles...
I hope eventually they release this information...
The repetition confuzzled me.
Makes me wonder why no one is planning orbiting radio satellites to increase this sort of radio reception resolution?
Some people have no sense of humor.
/sigh...
Think it through, he isn't bitching about the slashdot moderation system, he's talking about _actual_ _karma_. The thing being saved is the mission (not some post).
See, that makes it a classic contextual justaposititon, which is at least a little amusing. I beginto think that we really do need the imaginary TNT service from those TV comercials. You know "is this funny?" "Yes, sir, you may laugh, but not that much..."
I wish the meta-moderation system would let me pick and choose what to meta-moderate...
Innocent people shouldn't be forced to pay for inferior software development.
--"Code Complete" Microsoft Press
It's a repeat. Spectrum ran an article on it as well, and it's actually been pretty well covered, just not in the past... mmm... month or so.
---
Mod me down, you fucking twits. Go ahead. I dare you.
(I read with sigs off.)
Did anyone watch the Daily Show where Jon Stewart was covering the Huygens probe and every time he said Huygens he said it like Professor Frink from the Simpsons? Huuuyyygens!!! Now whenever I see that word I immediately laugh:
Professor Frink teaching a kindergarten class, pushing one of those popcorn popper thingies with the colored balls inside:
Frink: "N'hey hey! Ahem, n'hey.... So the compression and expansion of the longitudinal waves cause the erratic oscillation -- you can see it there -- of the neighbouring particles."
[Girl raises hand]
Frink: Yes, what is it? What? What is it?"
Little Girl: "Can I play with it?"
Frink: "No, you can't play with it; you won't enjoy it on as many levels as I do.... Mm-hai bw-ha whoa-hoa. The colours, children! Mwa-ha-lee!"
"When the president does it, that means it's not illegal." - Richard M. Nixon
Another difference is that the radio telescopes only read the velocity component along a Earth-Huygens line, as opposed to a Cassini-Huygens line. I don't know which component would have been more scientifically useful to have, but having both of them would have been really great, even without taking into account the higher precision of Cassini's data.
Shouldn't that be "In Soviet Rush, You Get High on Tom Sawyer"?
-- Too lazy to get a lower UID.
Its interesting you mention this, because after viewing the original game, and the online version, I've come to a rather startling conclusion:
Not only was the online game awful, the original game was almost as bad. The games consists of building houses and motiving computer generated people.
Its sort of like masturbation, but atleast if you masturabate correctly, there's a payoff at the end. The sims is self-abuse, and the online game is like a particularly nasty S&M Session... you pay a lot of money, get a lot of pain, and you're ashamed and embarassed afterwards.
"How come when Europe does something, people claim that's it's a great European accomplishment and everyone salutes them."
;-)
Because they are sympathetic and the underdog (not neccesarely in that order).
"However when the USA does something and people claim it's a great American accomplishment, people get offended and feel the need to knock NASA?"
That's because, mostly, it's not 'people' in general claiming that, but rather americans claiming it of their own; an opinion not shared by many.
"It's almost as if the political climate on this forum supports the recognition of someone's feats only if they're considered an underdog?"
Your point being? If you want recognition that much, and if your theory is right, the only thing nasa/usa has to do is become the underdog.
--- "To pee or not to pee, that is the question." ---
However when the USA does something and people claim it's a great American accomplishment, people get offended and feel the need to knock NASA?
Because nasa means "crazy" in Toki Pona.
So, now they proved that the whole test was redundant and they could have carried a different piece of observation gear, or saved a lot of money or development, or...
Oh well, what the hell...
This great practically self-taught Indian mathematician might have said differently.
Also, a brief look into the history of mathematics will reveal a decimal system in use in India around 2100BC, the development of theories of a solar-centric solar system, and pi around 500 AD, and tangible proof of the development of zero and negative numbers around 650-ish AD (the 7th century, and yes, this is a huge accomplishment nit-wit). Additonally, the term sine is derived from an Indian word, as trigonometry originated there, though you likely never made it through algebra.
The contributions made by the people of the Indian subcontinent are far from trivial. Sounds like someone also needs a history lesson.
Of blankness, I know nothing.
Just to clarify, the "command" to turn "on" the oscillator for Channel A was not sent due to human error.
:)
Lager version at spacescience.ca
So that equates to no data sent to Earth from Cassini for that Channel which contains the wind data and half of the photos.
Channel B does not have a similar oscillator so it did not suffer from the same problem.
So my question is, what data did they get, (or could get potentially)?
Sounds like the photos will be lost because all they seem to have accomplished with the global radar conglomerate was a measurement of Huygens's Doppler shifting carrier wave signal.
This is probably not as accurate as the direct measurements but will give us a replay of the descent to within 1km thanks to some correlation to VLBI measurements taken on Earth also.
There is a heated debate between project teams going on in the background as to exactly where the probe landed.
So this data should do well to help pinpoint the location.
Because, I made up a collage, Titan's Huygens Collage
I'm interested in seeing more images. Knowing wind speeds is good data, but personally I'd much rather have more photos for my collage.
Whilst I do not doubt the wonders that NASA can perform, perhaps you should spare a little credit: reading the article on the ESA website it looks like a joint undertaking: the signals came from US and Aus (parks). The science team is European (as an ESA project), and the data was "processed jointly by scientists from the NASA Jet Propulsion Laboratory (JPL, USA) and the Joint Institute for VLBI in Europe (JIVE, The Netherlands) working within the DWE team."
Mmm, doh-nuts.