If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Bad Astronomy and Universe Today Forum > Space and Astronomy > Against the Mainstream
Register FAQ Members List Calendar Mark Forums Read

Closed Thread
 
LinkBack Thread Tools Display Modes
  #301 (permalink)  
Old 15-January-2005, 04:45 PM
Astronomy Astronomy is offline
Senior Member
 
Join Date: Nov 2004
Posts: 183
Default

Here's the profile from the ESA newsrelease:

Quote:
Following its release from the Cassini mothership on 25 December, Huygens reached Titan’s outer atmosphere after 20 days and a 4 million km cruise. The probe started its descent through Titan’s hazy cloud layers from an altitude of about 1270 km at 11:13 CET. During the following three minutes Huygens had to decelerate from 18 000 to 1400 km per hour.

A sequence of parachutes then slowed it down to less than 300 km per hour. At a height of about 160 km the probe’s scientific instruments were exposed to Titan’s atmosphere. At about 120 km, the main parachute was replaced by a smaller one to complete the descent, with an expected touchdown at 13:34 CET.
That's as good as it gets for now. Most of the monitoring instruments on the probe will be used to get a compositional profile for the atmosphere.

If you're really interested in tracking the probes descent, go here. The acoustic radar blips can be converted into a profile by taking the speed of light (unless you are going to argue that the speed of light isn't the same on Titan).
  #302 (permalink)  
Old 15-January-2005, 05:16 PM
Hamlet's Avatar
Hamlet Hamlet is offline
Senior Member
 
Join Date: May 2003
Location: Rochester, NY
Posts: 1,135
Default

Quote:
Originally Posted by Jerry
If you happen to have the descent profile for the Spirit and Opportunity missions, I would appreciate those as well, because to the best of my knowledge, NASA has never released them.
Really?

I posted the Mars Exploration Rovers Entry, Descent, and Landing Trajectory Analysis last week. This document shows the predicted EDL values and the actual values they've been able to reconstruct so far.

There are 16 reconstructed values for Spirit, of which only 1 value was outside the predicted range. There are 15 reconstructed values for Opportunity, of which 3 were out of range. Two of those three were only slightly over predicted.

Here is what the authors say:
Quote:
Also listed in Tables 3 and 4 are the trajectory conditions reconstructed thus far from the actual “Spirit” and
“Opportunity” flight data obtained during their respective landings. The reconstruction effort is still ongoing, however,
preliminary reconstruction results are shown for comparison to the pre-entry predictions. Accelerometer and
gyro flight data were recorded during both descents and the parameters that can be reconstructed from this data set
are listed. As seen, almost all the reconstructed parameters are well within the pre-entry predicted 3-σ variations.
However, there are a few parameters that are near or slightly exceed the 3-σ variation bounds (e. g., time of and αT
at parachute deployment).
Further on:
Quote:
The landing locations for both “Spirit” and “Opportunity” were within the pre-entry predicted footprint ellipses.
“Spirit” landed 13.4 km downrange from its predicted landing location, while “Opportunity landed 14.9 km downrange
from its predicted landing location. The reconstruction work is ongoing in order to gain a better understanding
of what transpired during the “Spirit” and “Opportunity” landings.
__________________
"A mystic is a person who is puzzled before the obvious but who understands the nonexistent." -- Elbert Hubbard
  #303 (permalink)  
Old 15-January-2005, 08:38 PM
Kaptain K's Avatar
Kaptain K Kaptain K is offline
Senior Member
 
Join Date: Oct 2001
Location: Elgin, Tx
Posts: 7,367
Default

Jerry,
Just in case you do not know, 3-σ is +/- 0.15%! If you want to argue with that, you are truely quibbling!
__________________
Any day you wake up on "the right side of the dirt" is a good day.

T. Anderson
  #304 (permalink)  
Old 15-January-2005, 10:31 PM
Jerry's Avatar
Jerry Jerry is offline
Senior Member
 
Join Date: Mar 2004
Location: Earth
Posts: 3,612
Default

Astronomy, this is absolutely unbelievable! Thank YOU =D> Is this real time? If it is, do you know what this means? There is a sudden, dramatic increase in the rate 25 seconds into the playback. After this, the pinging rate continues to accelerate right up to the end. If the "sudden increase" was when the small, fast descent parachute deployed, the second parachute was only deployed for 38 seconds! It should have been deployed for for at least 109 km, and the rate of descent should have been at a nearly constant 5 m/s for at least 36 minutes, (from 109km) not 38 second! And these bleeps are clearly accelerating at a non-linear rate!

If this interpretation is correct, Huygens figured out she was descending much too fast, calculated when to deploy the small parachute and released third and final parachute at about 140 meters. This is the rapid sequence 12.5 seconds into this series as the main chute tethers away from Huygens, and then springs taunt again. The main parachute stays on for another 12.5 seconds, and you can tell because the time between the radar pulses is measurably slower while the both the main and final parachute are deployed. Then the main parachute is jettisoned, at an altitude of only about 100 meters. From a descent rate of near 0.1m/s, Huygens plunged, accelerating rapidly for the last 38 seconds to a final velocity of 4.5m/s.

Obviously we need someone other than jerry to interpret this data before anyone will believe it. I get to be wrong, as always, because I am left guessing at two critical parameters: Is this real time, and does it mark the entire descent of the small parachute?

The caption says this is during 'the last few kilometers', and the events at 12.5 seconds and 25 seconds are clearly what would be expected if a second parachute is deployed, releasing the main parachute onto a drag line. (The time between pulses from 12.5 to 25 seconds is slower than during the first 12 seconds, indicating the presence of both parachutes.) Then the main parachute is cut, and Huygens falls 'almost' like a rock.

It would certainly explain the orange rocks, because you can have a lot of iron in a moon as dense as Mars!
__________________
jwj

If you always believe what you already know, you can't learn anything - Liz
  #305 (permalink)  
Old 15-January-2005, 10:35 PM
Jorge's Avatar
Jorge Jorge is offline
Senior Member
 
Join Date: Aug 2004
Location: Belgium
Posts: 745
Send a message via MSN to Jorge Send a message via Yahoo to Jorge Send a message via Skype™ to Jorge
Default

I'm not sure, i think i read this was puzzeld together of a lot of smaller clips, i might be wrong though
__________________
GCS/S d(+) s+:+ a--- C++(+++)>$ W+++>$ L>+ M+>++ w++ P+>++ tv@ PS b+ DI+ G e-> h! r-- !z+

~Jorge Schrauwen
  #306 (permalink)  
Old 15-January-2005, 11:30 PM
lek lek is offline
Senior Member
 
Join Date: Apr 2004
Posts: 290
Default

Quote:
Originally Posted by Jerry
Astronomy, this is absolutely unbelievable! Thank YOU =D> Is this real time? If it is, do you know what this means?
*snip the rest of the nonsense*
It means that you are apparently not interested enough of the mission to even check things yourself.
You are asking if ~1min audio clip is real time recording of an event that took ~1.5 hours? :roll:
And all the fuss about the parachutes is just as "accurate".
The proper order of doing things is : Read, Think, Post. You seem to have forgotten the first two.
  #307 (permalink)  
Old 16-January-2005, 12:43 AM
Jerry's Avatar
Jerry Jerry is offline
Senior Member
 
Join Date: Mar 2004
Location: Earth
Posts: 3,612
Default

Quote:
Originally Posted by lek
It means that you are apparently not interested enough of the mission to even check things yourself.
You are asking if ~1min audio clip is real time recording of an event that took ~1.5 hours? :roll:
And all the fuss about the parachutes is just as "accurate".
The proper order of doing things is : Read, Think, Post. You seem to have forgotten the first two.
...Not when you are trying to put together a scientific interpretation of NASA or ESA release data. They did not include in the posting the Doppler frequency, the angle of the radar relative to the ground, the time signature ect ect ect:

Quote:
Originally Posted by ESA
This recording was produced by converting into audible sounds some of the radar echoes received by Huygens during the last few kilometres of its descent onto Titan. As the probe approaches the ground, both the pitch and intensity increase. Scientists will use intensity of the echoes to speculate about the nature of the surface.
So I am stuck with 'the last few kilometers' and the fact that it is continuous (the acoustic data was spliced together), and includes the termination sequence on landing. Since they were expecting to impact at ~5m/s, a seventy second sequence should correspond to the last ~400 meters, not several kilometers. So I am stuck asking if anyone can confirm it is real time, but even more so, does anyone have a better or different interpretation?

FWIW, I spent more than three hours trying to piece that together, and an hour on the phone with other physicists.

Quote:
Originally Posted by Hamlet
Quote:
Originally Posted by Jerry
If you happen to have the descent profile for the Spirit and Opportunity missions, I would appreciate those as well, because to the best of my knowledge, NASA has never released them.
Really?

I posted the Mars Exploration Rovers Entry, Descent, and Landing Trajectory Analysis last week. This document shows the predicted EDL values and the actual values they've been able to reconstruct so far...
.
Yes you did, thank you and I combed through that data last week looking for something, anything that would allow me to estimate the acceleration of gravity on Mars - and every one of the parameters that would be useful to this end are missing from the paper! Including all the mach numbers, the heating rate (vr prediction) the peak stagnation pressure, total heat load, altitude at which the heat sheild jetisoned, dynamic pressure, sensed acceleration, and time from entry or parachute deployment to 'bouncedown'

How long does it take to reconstruct the peak pressure and sensed acceleration? How long does it take a rocket scientist to pinpoint the time of landfall? Are they camping on this data because, like the Viking data, they cannot recreate a plausible physical scenario?

(Although the time of landing would be a constraining parameter for estimating the gravity of Mars, for Huygens, the time of landfall is almost meaninless, since the second parachute was a timed, or programmed release after the deployment of the first parachute.)
__________________
jwj

If you always believe what you already know, you can't learn anything - Liz
  #308 (permalink)  
Old 16-January-2005, 12:53 AM
Maksutov's Avatar
Maksutov Maksutov is offline
Honored Member
 
Join Date: Jan 2004
Location: Fifth corner of the Earth
Posts: 16,731
Default Re: Potential Threat to the Huygens Mission

Quote:
Originally Posted by Jerry
[edit]FWIW, I spent more than three hours trying to piece that together, and an hour on the phone with other physicists.
So you have Lunatik's and John T's phone numbers?

OK, that's enough. This is like shooting fish in a barrel.
__________________
A person's name, or a mark representing it, as signed personally or by deputy, as in subscribing a letter or other document.
  #309 (permalink)  
Old 16-January-2005, 01:20 AM
Jerry's Avatar
Jerry Jerry is offline
Senior Member
 
Join Date: Mar 2004
Location: Earth
Posts: 3,612
Default Re: Potential Threat to the Huygens Mission

Quote:
Originally Posted by Maksutov
So you have Lunatik's and John T's phone numbers
...We just figured out the little blip at the first was the 'Front shield' being deployed. In the sequence, this occurs just before the final parachute deployment. The probe appeared to have been falling much faster just before the shield was released - there appears to be some echos bouncing off the shield as it falls. So either the time in this radar sequence has gaps in it, or the ending sequence was very tightly compressed.
__________________
jwj

If you always believe what you already know, you can't learn anything - Liz
  #310 (permalink)  
Old 16-January-2005, 03:24 AM
Jerry's Avatar
Jerry Jerry is offline
Senior Member
 
Join Date: Mar 2004
Location: Earth
Posts: 3,612
Default

Quote:
Originally Posted by Space.com
"It was impossible to transmit the entire soundtrack," said HASI principal investigator Marcello Fulchigoni, adding that the sounds he released today were reconstructed from snippets by researchers. "But we have the principal fragments of these sounds."...Tomasko added that 350 images during descent and continuing after Huygens' landing were received on the one working communications channel -- half the crop that would have been harvested had both lines been functioning.
OK, How do you only get half the data, and all of the principle components? I can understand half resolution, but an intermittant sequence that captures all the key elements, including the ending?

...Or did Huygens fall twice as fast as expected, and return half as many images because the mission had to be terminated early? The science teams could not image the scenario I have painted, so now I have to speculate again: Huygens fell fast, reaching the surface in half the expected time, but at ~200 meters, Huygens knew she was in trouble and completed the termination sequence early. Since everything was retransmitted, and they did not believe the radar - thought it was garbled, the ground troops think that they don't have a real time line...But they did recognize the sounds of the mission touch down sequence, and declared victory, simply guessing at the termination time. Possible? It is a dam good thing we have the Earth based Doppler data to help sort this all out!
__________________
jwj

If you always believe what you already know, you can't learn anything - Liz
  #311 (permalink)  
Old 16-January-2005, 04:43 AM
Kaptain K's Avatar
Kaptain K Kaptain K is offline
Senior Member
 
Join Date: Oct 2001
Location: Elgin, Tx
Posts: 7,367
Default

Quote:
Are they camping on this data because, like the Viking data, they cannot recreate a plausible physical scenario?
They are "camping" on the data becase it's their data. Those who conceived, designed, built and paid for the mission expect to get first shot at the data! NASA's policy is that all data is propietary for one year. After that, even if the data is released, there is no requirement that NASA put it on the public pages.
__________________
Any day you wake up on "the right side of the dirt" is a good day.

T. Anderson
  #312 (permalink)  
Old 16-January-2005, 05:56 AM
Taibak Taibak is offline
Senior Member
 
Join Date: Jan 2004
Posts: 504
Default

Quote:
Originally Posted by Jerry
Quote:
Originally Posted by Space.com
"It was impossible to transmit the entire soundtrack," said HASI principal investigator Marcello Fulchigoni, adding that the sounds he released today were reconstructed from snippets by researchers. "But we have the principal fragments of these sounds."...Tomasko added that 350 images during descent and continuing after Huygens' landing were received on the one working communications channel -- half the crop that would have been harvested had both lines been functioning.
OK, How do you only get half the data, and all of the principle components? I can understand half resolution, but an intermittant sequence that captures all the key elements, including the ending?

...Or did Huygens fall twice as fast as expected, and return half as many images because the mission had to be terminated early? The science teams could not image the scenario I have painted, so now I have to speculate again: Huygens fell fast, reaching the surface in half the expected time, but at ~200 meters, Huygens knew she was in trouble and completed the termination sequence early. Since everything was retransmitted, and they did not believe the radar - thought it was garbled, the ground troops think that they don't have a real time line...But they did recognize the sounds of the mission touch down sequence, and declared victory, simply guessing at the termination time. Possible? It is a dam good thing we have the Earth based Doppler data to help sort this all out!
Ummm... no. Not even close. If you had done any actual research on the probe, you would have found out that one of the two communications channels had failed due to a programming error. As such, ESA had only received half of the total amount of data they were expecting. They received all the important bits because most of the data was set to be broadcast on both channels. That has absolutely nothing to do with the probe's rate of descent.
  #313 (permalink)  
Old 16-January-2005, 06:18 AM
Jerry's Avatar
Jerry Jerry is offline
Senior Member
 
Join Date: Mar 2004
Location: Earth
Posts: 3,612
Default

[quote="Jerry"]
Quote:
Originally Posted by Jerry

...Or did Huygens fall twice as fast as expected, and return half as many images because the mission had to be terminated early? The science teams could not image the scenario I have painted, so now I have to speculate again: Huygens fell fast, reaching the surface in half the expected time, but at ~200 meters, Huygens knew she was in trouble and completed the termination sequence early. Since everything was retransmitted, and they did not believe the radar - thought it was garbled, the ground troops think that they don't have a real time line...But they did recognize the sounds of the mission touch down sequence, and declared victory, simply guessing at the termination time. Possible?
And now I have the PROOF! This rather large set of pictures is worth waiting for, if you have high speed: Look at the folder labeled "CAMTOP"

Quote:
Originally Posted by Jumpjack
I think I found the best source for titan images (Warning: 13 MB ZIP download!). The zip should (actually I don't know, I'm still downloading it... 8) )contain all the triplets, stored in separated files.
The very first image in the folder is the pano, meaning panoramic. This was suppose to be the first picture taken after the final 3 meter parachute deployed at 110-140 kilometers, it is the panoramic picture, but it is the same picture as almost two thirds of the images recorded on on the surface of Titan: The most important set of orange pebbles ever photographed. You have to look at it carefully - My wife picked it out - the panarama was not a panarama because the camera could not spin on the tether - It was firmly on the surface of Titan.

When the Panorama Picture was taken, Huygens was already on the ground because the law of gravity is wrong. It took the probe on the order of one hour to completely traverse the atmosphere, The 30 meter parachute jettisoning the heat shield less than 200 meters above the surface. Huygens spent thirty eight seconds descending on the 10 meter parachute, then took the panaramic photograph that was suppose to be taken while swiveling on a parachute at 100 kilometers, and then took 400-600 pictures of the same rocks, because the camera logic said it was still descending.

A new era in physics will finally emerged =D> Thank you Huygens, thank you Cassini, no thank you, ESA administrators who are still mumbling about lost data, who did not know how to interpret the data, so they made a bad guess about the time Huygens hit the moon, and dampe the spirit about the marvelous performance of their wonderful craft! -

Edited for Politeness

.
__________________
jwj

If you always believe what you already know, you can't learn anything - Liz
  #314 (permalink)  
Old 16-January-2005, 06:36 AM
Jerry's Avatar
Jerry Jerry is offline
Senior Member
 
Join Date: Mar 2004
Location: Earth
Posts: 3,612
Default

Quote:
Originally Posted by Taibak

Ummm... no. Not even close. If you had done any actual research on the probe, you would have found out that one of the two communications channels had failed due to a programming error. As such, ESA had only received half of the total amount of data they were expecting. They received all the important bits because most of the data was set to be broadcast on both channels. That has absolutely nothing to do with the probe's rate of descent.
I wish that were true, but if you look in the reference I posted above, you will fine the full thousand images - True 650 of them are on the ground, but that is because Huygens spent twice as much of the allotted time for the mission sitting on the ground as she did in the air.

I do not understand the mentality of the ESA - I can understand why they might be embarrassed and confused - but they must be honest.

And for any of you conspiracy theorists out there: This is why you are wrong: No agency with any depth or size can pull off a misdirection of the truth of any magnitude - the ground-based Doppler data will prove this in spades, just as the panoramic pictures of the ground, that were suppose to be taken just after the last parachute deployed at ~100km, and the Doppler data historically recording this sequence live - already have.
__________________
jwj

If you always believe what you already know, you can't learn anything - Liz
  #315 (permalink)  
Old 16-January-2005, 06:40 AM
dummy dummy is offline
Senior Member
 
Join Date: Jan 2004
Location: London
Posts: 198
Default

I wish I had the energy to headbutt the wall.
  #316 (permalink)  
Old 16-January-2005, 06:42 AM
01101001's Avatar
01101001 01101001 is offline
Senior Member
 
Join Date: Mar 2004
Posts: 9,912
Default

Quote:
Originally Posted by Jerry
A new era in physics will finally emerged =D> Thank you Huygens, thank you Cassini, no thank you, ESA administrators who are still mumbling about lost data, who lied about the time Huygens hit the moon, and lied about the marvelous performance of their wonderful craft!
This definitely belongs in Against the Mainstream!
__________________
0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 ...
  #317 (permalink)  
Old 16-January-2005, 06:51 AM
dummy dummy is offline
Senior Member
 
Join Date: Jan 2004
Location: London
Posts: 198
Default

Quote:
Originally Posted by Jerry
I wish that were true, but if you look in the reference I posted above, you will fine the full thousand images - True 650 of them are on the ground, but that is because Huygens spent twice as much of the allotted time for the mission sitting on the ground as she did in the air.
Actually there are 367 raw images. You've downloaded the set of data in which the pictures from the 3 cameras have been seperated (as the filename mentions) by the guy who's hosting them on that site.
  #318 (permalink)  
Old 16-January-2005, 06:57 AM
Astronomy Astronomy is offline
Senior Member
 
Join Date: Nov 2004
Posts: 183
Default

Quote:
Originally Posted by Jerry
The very first image in the folder is the pano, meaning panoramic. This was suppose to be the first picture taken after the final 3 meter parachute deployed at 110-140 kilometers,
I'm pretty sure this isn't correct. The panoramic is simply a composite.

Quote:
it is the panoramic picture, but it is the same picture as almost two thirds of the images recorded on on the surface of Titan: The most important set of orange pebbles ever photographed. You have to look at it carefully - My wife picked it out - the panarama was not a panarama because the camera could not spin on the tether - It was firmly on the surface of Titan.
Tether? Maybe you can point out where the tether is? Huygens

Quote:
When the Panorama Picture was taken, Huygens was already on the ground because the law of gravity is wrong.
No, the picture taken from above was not the one you're referring to. It was this one: http://esamultimedia.esa.int/images/...d/Picture3.jpg

Quote:
It took the probe on the order of one hour to completely traverse the atmosphere, The 30 meter parachute jettisoning the heat shield less than 200 meters above the surface. Huygens spent thirty eight seconds descending on the 10 meter parachute, then took the panaramic photograph that was suppose to be taken while swiveling on a parachute at 100 kilometers, and then took 400-600 pictures of the same rocks, because the camera logic said it was still descending.
That's not what happened either. It's not a good idea to jump to conclusions like this.