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Unmanned Spaceflight.com > Outer Solar System > Saturn > Cassini Huygens > Titan
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djellison
Nasa TV will be starting coverage in about 3 mins - but I'm watching multiple TV channels to see if any carry coverage - and will post any news thru the day as it happens

Doug
chris
There goes my productivity today :-)
djellison
Signal detected - it's survived entry smile.gif

Doug
djellison
It's on the parachute and a signal is still being recieved biggrin.gif

Doug
Sunspot
biggrin.gif biggrin.gif biggrin.gif

I wonder if they will still be able to pick up the signal even after Cassini has passed out of range.
TheChemist
QUOTE (Sunspot @ Jan 14 2005, 01:11 PM)
biggrin.gif  biggrin.gif  biggrin.gif

I wonder if they will still be able to pick up the signal even after Cassini has passed out of range.

Batteries will run out soon, unfortunately sad.gif
Go Huygens ! (where is that Titan emoticon when we need it ? tongue.gif )
YesRushGen
According to NASA's coverage schedule, we were supposed to have commentary from JPL at 6:30 EST, but that didn't happen.

Still waiting for 7:30am EST back from ESA.
TheChemist
According to the latest commentary, the signal is still being received, and there is evidence that the Doppler experiment is being conducted successfully.
Next update from ESA not before 17.15 CET.
Bjorn Jonsson
It seems Huygens landed between 13:35 and 13:36 CET. A signal is still being received, meaning it survived the landing.
BruceMoomaw
It's been confirmed that Huygens has survived its landing, and is still sending a signal detectable by the Earth radiotelescopes an hour after Doppler data indicated a landing at 4:35 AM Pacific time (19:35 UTC).
Bill Harris
Are there any mirror sites for the ESA and CICLOPS sites? I've tried those "known official sources" and haven't been able to get in. I suspect that most everyone else in the world is trying to, too...

Huygens evidently made it, now if it returned data... whew.

--Bill
BruceMoomaw
As of 6:03 AM (about 90 minutes after landing), Huygens continues to transmit.
Bjorn Jonsson
Huygens was still transmitting as its landing site dropped below Titan's horizon as seen by Cassini.
Baltic
QUOTE (Bjorn Jonsson @ Jan 14 2005, 03:11 PM)
Huygens was still transmitting as its landing site dropped below Titan's horizon as seen by Cassini.

Yeah, 2 hours after landing! biggrin.gif

Tom
TheChemist
Great ! Just like the MERs, power is not a problem.
Oh those images, where are they ? smile.gif
Baltic
QUOTE (TheChemist @ Jan 14 2005, 03:59 PM)
Great ! Just like the MERs, power is not a problem.
Oh those images, where are they ? smile.gif

On their way to earth I hope! smile.gif

Tom
volcanopele
Is it still the case that the Earth-based tracking stations would be able to pinpoint Huygens location on the surface fairly accurately? Or did I hear incorrectly?
volcanopele
They're clapping. That's a good sign.
Bjorn Jonsson
Seems some servers are swamped now, I hear only occasional sounds on NASA TV. But I heard a few seconds of clapping...
Sunspot
FRIDAY, JANUARY 14, 2005
1619 GMT (11:19 a.m. EST)

The Huygens data is being received! Applause has erupted in the German control room after the tense and anxious wait. It will take some time to begin examining the information. The first pictures from Huygens could be released later today, if all has gone well.


http://www.spaceflightnow.com/cassini/status.html
M_Welander
At the moment I've found this webcast to be of somewhat higher quality than the main NASA TV webcast:

http://quest.nasa.gov/ltc/ram/nasalive-v.ram
Sunspot
Three thumbs up...thats got to be a good sign lol biggrin.gif
Baltic
Damn, I can't see or hear anything from the news conference. mad.gif

Tom
Sunspot
I've been watching it here: http://www.unitedspacealliance.com/live/nasatv.htm

Not great quality though
M_Welander
I've found a really good webcast now:

http://science.ksc.nasa.gov/cgi-bin/rrg2.p...coder/nasatv.rm

Not a single skip the last ten minutes - though I suppose it'll start breaking up now that I've said it doesn't. smile.gif
Sunspot
The sound on mine has gone.....whats the latest?
Bjorn Jonsson
I heard a short burst of sound - seems all the experiments did get good science biggrin.gif
tedstryk
Something occured to me...will the Huygens data remain just at ESA, or will it make its way to the NASA PDS. I hope it ends up in the PDS system, especially the DISR data....NASA is much better with access.
M_Welander
They believe they have got all the data from all experiments on Channel A (or B - there's some confusion?), however, the redundant Channel B (or A?) appear to be blank.
Mongo
Second try with this post ... the first try seems to have vanished.

According to the current ESA news conference, we are receiving every packet of science and engineering data with no drop-outs. The first 30 minutes of the descent profile was nominal, with the main parachute deploying within 15 seconds of the predicted time. The spin rate of the probe is also nominal.

Bill
M_Welander
The first images could be made available in a little over 2 hours from now.
volcanopele
QUOTE (M_Welander @ Jan 14 2005, 10:11 AM)
They believe they have got all the data from all experiments on Channel A (or B - there's some confusion?), however, the redundant Channel B (or A?) appear to be blank.

Channel A, mostly images, maybe blank. This would mean that we lost half the images.
Baltic
QUOTE (M_Welander @ Jan 14 2005, 04:51 PM)
I've found a really good webcast now:

Thanks for the links, you saved my day. smile.gif

Tom
volcanopele
The "fog" light on Disr came on biggrin.gif
imran
QUOTE (volcanopele @ Jan 14 2005, 05:24 PM)
QUOTE (M_Welander @ Jan 14 2005, 10:11 AM)
They believe they have got all the data from all experiments on Channel A (or B - there's some confusion?), however, the redundant Channel B (or A?) appear to be blank.

Channel A, mostly images, maybe blank. This would mean that we lost half the images.

Are you sure about this? Because according to Spaceflightnow the Doppler Wind Experiment may only have been affected.

"One of Huygens' six experiments, the Doppler Wind Experiment, relied in part on chain A of the probe's communications system. It was designed to measure wind speeds by detecting subtle changes in the frequency of radio transmissions as th craft is blown this way or that. If chain A did not work, scientists will lose measurements of that shift between Huygens and Cassini. But Sollazzo said similar measurements from Earth-based radio telescopes will allow scientists to collect similar data to make up the shortfall, assuming the data on chain A is, in fact, lost. "
volcanopele
QUOTE (imran @ Jan 14 2005, 10:40 AM)
Are you sure about this? Because according to Spaceflightnow the Doppler Wind Experiment may only have been affected.

"One of Huygens' six experiments, the Doppler Wind Experiment, relied in part on chain A of the probe's communications system. It was designed to measure wind speeds by detecting subtle changes in the frequency of radio transmissions as th craft is blown this way or that. If chain A did not work, scientists will lose measurements of that shift between Huygens and Cassini. But Sollazzo said similar measurements from Earth-based radio telescopes will allow scientists to collect similar data to make up the shortfall, assuming the data on chain A is, in fact, lost. "

I just sat in on a status report meeting and they mentioned that Channel A did not downlink and this would cause the loss of half of the DISR images.
azstrummer
Well, half's better than none. Shame the loss is in the images though. How many images are we talking about during the mission duration?
Bjorn Jonsson
That's weird, I understood A and B were redundant with one of the streams transmitted with a short delay to ensure fewer dropouts.
pioneer
QUOTE
I just sat in on a status report meeting and they mentioned that Channel A did not downlink and this would cause the loss of half of the DISR images


Aren't channel A & B redundant channels for Huygens to transmit the same data?
volcanopele
QUOTE (pioneer @ Jan 14 2005, 10:52 AM)
QUOTE
I just sat in on a status report meeting and they mentioned that Channel A did not downlink and this would cause the loss of half of the DISR images


Aren't channel A & B redundant channels for Huygens to transmit the same data?

As far as I know, they are not the same data. Maybe you are confusing this with the fact that Huygens will be retransmitting its data several times?
pioneer
dry.gif Perhaps I'm thinking of the Galileo atmospheric probe. Still, I think speculating that half the images are lost is a bit premature at this point.
DavidVicari
QUOTE (volcanopele @ Jan 14 2005, 05:55 PM)
As far as I know, they are not the same data. Maybe you are confusing this with the fact that Huygens will be retransmitting its data several times?

No... Huygens will not be re-transmitting its data several times. It sent all its data out in almost real time on two separate redundant channels. One channel was supposed to be delayed by something like 6 seconds so that a temporary comm. loss would not lose data.

Cassini will send its recorded data to earth multiple times and from multiple different memory locations.
john_s
This statement doesn't sound like half the images are lost:

From Spaceflight Now:

Engineers at the European Space Agency's Space Operations Center in Germany are receiving data from Huygens on chain, or channel, B but not from chain A. Both systems are identical and scientists should receive almost all of the desired data from chain B, Mitchell said.

"The way the probe system works, there are two transmitters on the probe and there are two separate receivers on the orbiter so we have two separate, distinct data links between the probe and the orbiter," he said. "These data links were deigned to be largely redundant, not 100 percent, but nearly so.
volcanopele
QUOTE (DavidVicari @ Jan 14 2005, 11:04 AM)
QUOTE (volcanopele @ Jan 14 2005, 05:55 PM)
As far as I know, they are not the same data.  Maybe you are confusing this with the fact that Huygens will be retransmitting its data several times?

No... Huygens will not be re-transmitting its data several times. It sent all its data out in almost real time on two separate redundant channels. One channel was supposed to be delayed by something like 6 seconds so that a temporary comm. loss would not lose data.

Cassini will send its recorded data to earth multiple times and from multiple different memory locations.

Sorry, I meant Cassini will be retransmitting Huygens data several times for redundancy.

Even though Channel A "may" be lost, DISR will still have plenty of nice looking panoramas from the data on Channel B. The Doppler Wind experiment data can be reproduced from the carrier signal on earth and from other Cassini instruments.
M_Welander
From what I've understood, the physical channels A and B (that is, the mechanisms used to create the channels) are redundant. However, the data from the instruments - which are not redundant - is interleaved between the channels in order to use this physical redundance to double the amount of data that can be transmitted during the short time available.

I could be wrong, though. But if I'm not, imagine this scenario, with a sequence of images:

ABABABAB

Now, if we're losing all A's, we'll still be able to get most of the science out of the B's, because we know where the A's where and so by looking at the B's can know what we've lost, either through interpolation or image reconstruction or reprojection or any other means of data recovery.
azstrummer
Ah man, wouldn't you know Sean O'Keefe would use a day like today to do some stumping for his boss and his "grand plan" for space. His speech on NASA TV, even though he touched on Huygens briefly, really rubs me the wrong way. It's like walking into someone's birthday party and announcing you're getting married.
Mongo
One of the questions during the ESA press conference was something like, "what effect will the apparent loss of Channel A have on the scientific results".

The answer given was that there should be very little effect, as the two channels were almost completely redundant. The sound dropped out for me right when the possible effects on the specific experiments were being discussed, but from what I heard, most of the experiments had their data completely duplicated on each of the two channels, while (one or two experiments) split the data between the two channels. One of those 'one or two' experiments would have been the Doppler Wind Experiment, but I don't know which--if any--other experiment may have lost data.

Bill
volcanopele
QUOTE (Mongo @ Jan 14 2005, 11:20 AM)
One of the questions during the ESA press conference was something like, "what effect will the apparent loss of Channel A have on the scientific results".

The answer given was that there should be very little effect, as the two channels were almost completely redundant. The sound dropped out for me right when the possible effects on the specific experiments were being discussed, but from what I heard, most of the experiments had their data completely duplicated on each of the two channels, while (one or two experiments) split the data between the two channels. One of those 'one or two' experiments would have been the Doppler Wind Experiment, but I don't know which--if any--other experiment may have lost data.

Bill

DISR has half their images on Channel A and half on Channel B
tedstryk
The good news is that other than doppler wind data and half the images, everything else was in Channel B. So all data from the other instruments should be recovered.
gpurcell
Ugh. This sounds bad for the DISR images.

How is the data interwoven between the channels? We we lose whole shots, will there be missing patches within shots, or will the image be or lower resolution?
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